Hi Andreas. Nice, but quite tough topic. We work a lot with CAN bus at work, various types. Yes, there are several different bus systems, different voltages, different speeds, different protocols, even diifferent number of wires. So many chances to do stuff wrong. Can't wait to see the 2nd part of your video. Good luck with the CAN, and cheers to BOSCH for inventing it in the first place.

Other possibility: Get a $5 OBDII-Bluetooth adapter, link to you phone and use one of the apps to check / reset codes ...

Hi, Volvo uses K-line and 2 CANbus:es, one Low-Speed and one Hi-Speed. Low-Speed is on pins 3 & 11 (OBD) High-Speed is on pins 6 & 14 (OBD) 1999-2004: Low-Speed: 125 kbps Hi-Speed: 250 kbps 2005-: Low-Speed: 125 or 250kbps (Unsure) Hi-Speed: 500 kbps Not all units are connected to both busses. The CEM (Central Electronics Module) is kinda like a router/firewall for the CANbuses, especially to and from the OBD port. It needs a periodic keep-alive message on the K-Line interface to "open" the firewall for the OBD CAN into the real CANBus network. K-Line baudrate: 10800 or 10400, 8N1 Msg: 84 40 13 b2 f0 03 7c Send it every 5 secs or so.

Don’t get me wrong and this is a fun project, but … there must be somewhere a message stating getting the issues diagnosed, checked and fixed must be the way to go. Just throwing away or resetting error messages all day long can cause quite some severe issues in the (not so) long term. If a sensor prevents the engine to run, it could be caused by a sensor that fails the engine management to tell in which phase the engine/cylinder is. This info is crucial to inject fuel and spark at the right time. That said, bring on part 2 !!

With you brother's expensive diagnostic tool ,and your logic analyser you could rule the ODBII world! :-)

I was waiting for this kind of video from you Andreas and here we go. Many thanks for this and I can't wait to see the next one.

Andreas! I have THE same car, even same colour and rims. And like yours it's starting to show it's age. I NEED you to finish this project so I can keep my old companion running.

great project 👍 thanks for sharing your experience with all of us 👍🙂

Hi, the MCP2515 offers two filter masks and 5 address filters, you can use these to filter out messages from control-units you are not interested in - and bring down the 1500 packets/s to a more reasonable amount. In my project though I had to set the device into loopbackmode to successfully set the filter and into normalmode afterwards. I'm very interested in interfacing with cars via can-bus and very keen on your follow-up video. If you'd like more info about how I implemented filtering let me know! 😃

I'm looking forward to hearing more about this from you as you continue with this project. As always, thanks for sharing what you do in videos like this.

Nice! Can't wait for the follow up video. I have a similar project in my TODO list, except for different purposes: My brother has a broken dashboard (with intermittent malfunction) so he purchased a second hand dashboard (the new ones are ridiculously expensive). The problem is that now the kilometers on the (new) dashboard do not match the kilometers on the ECU. Because of that, the vehicle fails the annual obligatory inspection. I'm hoping to learn something on how to approach my build. :)

Very interesting project! Thanks again Andreas!

Another interesting piece of information. Thank You ! As others already suggested I use the elm327 bluetooth dongle in two ways. First to read and reset errorcodes for repair via "torque" android app and plugins. Second to display some data not available in the cars instrument cluster via a ttgo tdisplay and obd arduino libraries but all are working random on reconnecting bluetooth ..... WIP.....

Waiting for the next video. I'm very happy for the reference on 07:00!

Hallo Andreas, you opened a whole can of worms - so to say ;-) I applaud your determination and methodical approach! But there are much easier ways to clear those pesky DTCs. One of the easiest is to use a Chinese clone of the ELM327 Blue-tooth adapter and the Torque application on your phone. There are also several other free Soft wares for use with your Laptop - if you are so inclined. Careful with clearing DTCs before going to technical inspection, since it will result in a "p1000 obd2 cycle not completed" DTC. Some cars seem to have built in random error generators - maybe to generate additional income for the dealers ?? Honi soit qui mal y pense...

This is both interesting and useful. I can now make me one too. Thanks a bunch for going down a path that will make any car dealership cringe with disbelief that average people can figure out how to repair something as complicated as a car computer. Good day to you from USA. vf

Nice concept ! I've just bought an elm327 USB device , an OTG cable , connected to my Android phone and used an app to reset ,diagnostic my car, this is more convenient to me than using a big laptop!

Very cool video. We pray for you success)

Hello Andreas, interesting video. I work for some time in this domain and I think deleting the DTC's is not a good idea. The purpose of DTC's is to indicate to the driver that there is an error and to the mechanic where the error is. The sensors are read cyclically (every few ms) and if one of them has an error the SW goes into a state then a DTC is set as present-active. Sometimes you can clear this type of DTC's but they will be set again in few ms because the error is still present. The car will not start because the SW is in a "locked" state not because the DTC is present. If after a while the sensor is read correctly then the DTC is set as present-inactive, to indicate that there was an error in the past. You can clear this type of DTC's but then you will not know where the error was (I think this is your case) If the car does not start my suggestion is to disconnect the battery for few seconds, this will reset the electronic devices. I made a trace of some communication. In the traces I am connected directly to an electronic device but on the real car there are multiple CAN buses and the central computer acts as a gateway (server). The OBD is connected to the central computer so your communication will look a little different. Clearing some DTC's might require the car to be in a specific session like "Extended session" or "Diagnostic session" and entering in some of them require security access. This is done automatically by the expensive diagnostic tool depending on the VIN of the car. My suggestion is to record the requests sent by the expensive diagnostic tool (I think only the clear DTC should be enough) and replay it using the Arduino to see if it works. Trace from car manufacturer 1: Time Dir ID Data [+] 5.210535 Tx 64A [02] 10 01 [00 00 00 00 00] -> 0x64A = id of transmitter, 0x02 = nr of bytes with useful information, 0x10 01 = default session, 00..00 = dummy data. Data comes usually in 8 bytes packages [+] 5.211018 Rx 6B4 [06] 50 01 00 32 01 F4 [AA] -> 0x50 01= positive response. If the response = 0x40 + request, you get positive response, if the response is 0x7F you get negative response [+] 17.856905 Tx 64A [02] 3E 00 [00 00 00 00 00] -> 0x3E 00 = tester present, this is usually sent cyclically to keep the device in a special session [+] 17.859119 Rx 6B4 [02] 7E 00 [AA AA AA AA AA] -> 0x7E = positive response (0x40 + 0x3E), 0xAA - dummy data [+] 37.954872 Tx 64A [04] 14 FF FF FF [00 00 00] -> 0x14 FF FF FF - clear all DTC's [+] 37.956562 Rx 6B4 [01] 54 [AA AA AA AA AA AA] -> 0x54 - positive response [+] 44.731985 Tx 64A [03] 14 FF FF [00 00 00 00] -> 0x14 FF FF - try to send incorrect command (it should need another FF) [+] 44.734359 Rx 6B4 [03] 7F 14 13 [AA AA AA AA] -> 0x7F - negative response Trace from car manufacturer 2: Time Dir ID Data [+] 424.415898 Tx 73A [02] 3E 00 [+] 424.425278 Rx 63A [02] 7E 00 [+] 427.682021 Tx 73A [02] 10 01 -> default session [+] 427.705014 Rx 63A [06] 50 01 00 32 01 F4 [+] 431.508870 Tx 73A [02] 10 03 -> extended session [+] 431.524970 Rx 63A [06] 50 03 00 32 01 F4 [+] 436.152013 Tx 73A [04] 14 FF FF FF [+] 436.214631 Rx 63A [03] 7F 14 78 -> negative response, device is processing [+] 436.424719 Rx 63A [03] 7F 14 78 -> negative resp. [+] 436.544580 Rx 63A [01] 54 -> positive resp.

good luck! :) Lovely project

Diagnostic connector is often on a "gateway" between the several CAN buses in a vehicle. The drivetrain bus can operate at 2 megabits per second and the "convenience ' bus as slow as 125 kilobits per second. The gateway routes messages between buses, depending on what device has registered an interest in that message type... which can be somewhat dynamic but is often coded into devices such as the gateway. The protocol was designed (obviously) by committee with scant regard for the sanity of those who implement it. It's nice in principle but the details are a swill.

If someone was up to the task of recreating the expensive scanner tool as open source, millions of mechanics would love that :)

good luck with this project is very interesting

Muy buen video gracias señor

My mother has a Volvo XC 70 of about the same vintage as yours. That car is too smart for its own damn good. In her case, the engine faults actually warranted an engine shutdown (oil pressure problem), but we would have really appreciated a more helpful message than a service warning on the dashboard. It ended up being her oil catch can, which hadn't ever been checked, was full up to the point it was slightly interfering with oil flow. Still, that was a US$1000 dealer service visit I could have fixed myself. Volvo makes a great car, but this is definitely a shortcoming.

Very interesting. The check engine/Alarm signals are related to the printer manufacturers who will not let you scan with empty ink cartridges. As the owner of the car I want to control which alarms are worthy of my attention. Looking forward to next chapter.

i'm looking forward to updates on this!

i find it hard to believe a volvo would break down, they're one of the most reliable cars on the road

I see the library also works with ESP32. But you need a transceiver. Do you know if there are any boards with CAN for ESP32, or I should build it myself?

Hoi, super projekt! Bin an was ähnlichem dran aber was ich mich frage ist das der CanBus aus dem OBD2 eine zu hohe spannung hat. Bricht das shield das auf 5v runter oder wie hast du das gemach?

Thanks for video and subtitles in Portuguese

I think CAN analyser software is very useful for this sort of thing. There is a python library called python-can that can be used with many different CAN interfaces, including CAN messages converted to serial (e.g. from your arduino). Maybe the live message viewer could help you identify the diagnostic tool messages (they would only be sent once when you request the code reset).

Looking forward to your next video on this. I have an OBD2/CAN reader tool that is sort of mid level ~85 USD that will read and reset codes on each of my various vehicles, Ford, Saturn, Honda, Jeep, Hyundai, and Mercedes. They range from 2000 to 2019. Not quite ready to tinker with my 2018 E63s AMG's bus but wouldn't worry too much about the Saturn :) Beyond resetting the DTCs, the next step is controlling features of the car. For example, my Mercedes shipped with intelligent LED lighting that is capable of operating with the high beams on all the time and just cutting out a box of light for oncoming traffic or for cars in front of you, however due to US DOT regulations the intelligent feature is disabled for US cars and we only get simple high beam low beam operation. Thankfully, the US recently changed this law so smart headlights are coming soon. In the meanwhile, it is possible to recode the car via the OBD2 connector and make it think this feature is enabled. Driving the car at night on the highway with this feature enabled, well it's like night and day difference almost :-). Other interesting features to play with depending on the vehicle. I wonder if the Raspberry Pi with more capability and ready access to Python and more space for libraries would be a good platform to start from for the more advanced bus fiddling?

I also did some investigations with the CAN-bus and ODB2 in the past. Not only for resetting error codes, but also to set certain behaviour of the car, e.g. the behaviour of electrical side mirrors, behaviour of lights when leaving the car and so on. I bought a device called obdeleven which is able to do all these settings. It is not too expensive, but for every change you want to do you have to pay. So I tried to sniff the packets. I found a software for Arduino for sniffing and serial dumping raw data from the bus. The library "Mechanic - Hacking Your Car Version 0.6" from Joerg Pleumann still works well, although being from 2013. It has several examples, one is a sniffer. There was also an article about this in german magazin "c't hacks" from 2013. With the sniffer I got tons of packets when setting certain behaviour of the car (e.g. side mirrors), all of them not standardized. After hours I gave up trying to understand them. I have a simpler device called "Ysding JD-101" which is able to delete error codes. Maybe I should try to sniff that device.

wow what a great video thank you a lot u gained yoursel an other subscriber is the second part ever comming soon?

Question: is it possible to set off an airbag if one by chance sends the wrong command? That thought has always kept me from experimenting with the CAN bus in my car so far.

I have a cheap Autel block that plugs into the OBD-II port and works with a phone. It was less than $99 US at Walmart. I have reset errors and the diagnostics and CAN messages are very good and reports can be generated in PDF and emailed . Worth every penny.

I've got one of Voltlog's units myself without an ECU car lol.... My plan is using those CANBUS rain sensors in trashed cars for a lora weather station.

Hey Andreas, This is Mohamed 7X3TL, I have been fiddling with CAN Bus for a little time now on my Peugeot 207. And to say the least my car has 4 CAN buses, two of which are exposed thru the OBD connector, pins 6 and 14 are for ECU CAN and pins 3 and 8 are for diagnostics, I made a little app using Delphi to read the messages and interpret them I get a lot of sensor data that are given by the ECU automatically, but as of yet, I havent been successful in getting the DTCs from the Diag Bus, still trying though. Keep up the good work, totally a fan here!

Are you making sure you don't reset more than just the alarms. So that the ECU don't revert to a kind of 1st startup every time you do this? hence it need kilomenters to tune in your driving, tune fuel to air mix ratio, etc. Seen a few try similar before, and actually in practise, doing the same as disconnecting the battery would do. So fuel consume went up and more.

Have you tried turning it off and on again ? :) unhooking the battery for a few minutes may also correct the problem .

can you tell us in ur case what repairs have you done on your 16 year old volvo?

We might get some fun car projects here! Also this car is old enough not be overcomplicated so you might have some cool additions like the garage opener on the Harley but more built-in

One of the few remaining fields where you can save serious money by DIYing :)

I've done car CAN-bus decoding. The hardware level is easy. You'll get those message, but the interpreation what those message mean is non-trivial. To decode it, you need a car maker and often model and year specific lookup table. In this table you'll find info like this: Message 100: 8 bytes length, 6 bits of information A, 3 bits of information B, .... Sometimes you even need a formula to make "useful values" out of it. Like temperature where it you need to extract the relevant bits, make a number of it and multiply with 10 and add an offset of -30. Fun stuff like this. Maybe you are lucky and such a lookup table got leaked or reverse engineered for your car. OBD2 is just a subset of those message where the "which bit mean what" is specified across makes and models. Another thing that should be open for right of repair stuff. But the manufacturers will fight this with every method they can. You could build amazing stuff if that data is know. As said, been there, done that. But the table was under NDA and sadly not the make and model of my personal car :(

I had a similar issue and used a cheap ELM327 Bluetooth module with an Attiny85 which monitors a button and sends the reset over UART to the ELM327.

Interesting timing. I received and tested out my Panlong bluetooth OBDII adapter that was amazingly cheap to buy online. I paid a little more from an eBay seller so to get shipped sooner... though ~$13 is a way better price that what I first paid for (~$67) and returned once I found the ELM327 & Panlong versions. I'm only using Hybrid Assistant on Android LG G4 phone for now to display engine coolant temp since I blocked my engine radiator grill 100% a few weeks back. Amazing what is capable with better software... days when would be nice if there were better open source protocol/communication analyzers for the LA's.

I had a problem with a faulty crank sensor on my car. I used the ELM327 Bluetooth dongle and a app on my phone the pro version and was able to find the problem and to reset after replacing the sensor. The dongle is now kept in the glove box off the car.

You are very interesssssting guy

If the warning light would be off in my car, that is the time to worry! It always reports some error concerning O2 levels IIRC, but it passes MOT, sensors where switched but error remains. Hope you have success.

I carry one in my camper van because I cannot push it! Chinese ELM327 about $4 and it connects by Wi-Fi to an app on my phone. Shows me the fault list and clears it as well as all the live data. But that’s not really the point, is it… Good luck!

In emergency usually you can still unplug battery for some time to clear the dtc errors, the time depends on the car.

Been there, done that. I bought a cheap one (25 EURO), with the reset functions available and it always stayed in my car. If I'm not mistaken, there are can bus parameters that are proprietary to the car manufacturers and can only be read/reset using the genuine software libraries. This equipment is rather expensive.

I have a suggestion. Have your brother connect up his diagnostic device, and snoop the can bus as he sends the rest command for your model of car. I have a feeling each model of car is different, this is probably why the cheep obd2 don't have reset.

What model Volvo? Looks like a 2006 XC90? I have an '06 XC90 and my OBDII dongle actually made the computer restart when I was driving.

i wonder how this OBD2 port could be used via 433hz devices to send all those cool data to your home. some tires are already sending their pressure to my RTL dongle, but im more interested in the weather (or at least my own car :D)

I would love to get a scanner for my old Holden Monterey (Trooper, Bighorn, Acura, Horizon, Monterey et al)) with the 4JX1 diesel engine but it doesn't respond to any ODB2 readers/scanners - it has the plug though, so I figure it must support an older protocol, so this project would be very interesting to me.

I would like to read obd2 value and put then in a display, so I can later use value of rpm readed and every time rpm are between 1500 and 2000 activate an water pump. Is it possible?

The reset often has to be done under specific combinations of key position and engine condition (typically off with key in run position). You sketch would need to run at the appropriate time for your car.

I can highly recommend the OBD2 sniffers from Freematics. Those are designed for Arduino and ESP32 with cellular connectivity!

Post this to SwedeSpeed! There are many of us who get up to Volvo CAN shenanigans. Sorry to hear that your P2 XC90 let you down there. They're usually so reliable.

Hi Andreas, I've done some projects with the ESP32 and the internal can transceiver or the teensy 4.0 and there two internal can transceiver to control electric power steering pump or use it as a hmi for the megasquirt ECU. But in your point, the fastest way to find the error reset is, to connect your Arduino sniffer between the car and the diagnostic tool and sniff the error reset command. Greetings from Germany Andreas

I am looking for micropython CAN module for ESP32, wroover e. Thanks in advance for any info.

Hi Andreas, you can use ESP32's built in CAN controller and CAN transceiver such as TJA1050/1040. Personally I've found more consistent results with TJA1040, plus it support low power standby mode. Problem is, TJA1050/1040 are 5V devices, so logic level converter is a must to communicate with ESP32.

I have that on a Renault forces me to wait from 15 to 20 minutes to try to restart again if it fails the first time I need to wait 20 minutes more, so far the I have replaced all possible sensors causing the failure and all possible cables whiteout luck, Would be great if you get this to work on your car , will take a look and see if it weeks on mine without more modifications.

I have an *AUTEL,* but not the pro. It works quite well. So it would be great if one of your viewers has a solution for this project!

I've currently built a K-Line and CAN sniffer, based on an ESP32 which writes anything onto a SD card. But I'm also struggling to find the right data 🤷🏻‍♂️

Hi Andreas! My solution to that problem is a 12USD/CHF ELM327 OBD2 to Bluetooth dongle along with the "Torque" app. The app cannot only display and record driving data. It can as well reset errors. Though I still had to replace the worn out (actually it was dirty) exhaust recirculation valve of my 2011 Mercedes Diesel to fix the issue. I hope you sensor will not need a replacement. Best regards from Limmattal! Adrian PS: Of course I'm still looking forward to part 2 of that video! :-)

Hi Andreas Spiess, can we put some our lcd display short video on your channel for advisetisement

Hello Andreas, I would try to find the .dbc file that translates the ids of your car on human lenguage. I use cantools library on python, but first try to find this .dbc file, may be on openpilot (comma ai). Happy learning!

I obly have minor experience with canbus so far but I am going to do a university project on it soon. I can only say that I am really skeptical that those few lines of code should do the trick. Can-bus is really complicated and has several varieties. I also recommend you replace that sensor 😅

Hello, I work with CAN in Automotive since 2008, very nice idea with the Arduino Shield and the OBD2 library, but I couldn't understand why the reset all DTCs doesn't work when you send it from Arduino? How good is the Arduino at logging the CAN communication, can you log all the messages? If yes, then just make a reset with the Tool and then decode the OBD2. If not, I recommend Peak Dongles on USB they are very cheap and can log all the communication. I always wanted to make a water temperature gauge for my car by using an ESP32, I think it has a CAN transceiver too? Do you know if the libraries work also on ESP32? Anyway I am happy to help if I can please contact me at this id over Gmail or here.

Maybe a resistor between the CAN bus and the fault analyzer could be used to see where it came from. If the pulse are higher on one side of the resistor the data direction can be detected.

I scrolled through most of the comments but didn’t see it: what sensor failed that shut the car down?

I needed a working one of those Monday... limp mode is not fun on an interstate highway.

Investigate purchasing a DiCE unit and VIDA. All the messages are there and explained as with block diagrams explaining every module in the P2 Volvo high speed / low speed CAN networks.

Each car maker allows a subset of CAN commands under a specific “session”. You can have: default, extended, supplier, diagnostic… In this case can you check if the code you are using is already switching to the proper session before sending the dtc clear command? You should see with the sniffer (when deleting with the expensive tool) something like 0x1003, 0x1011…

Hi Andreas, it is fine to use this resetter if it happened one time only. But if you are getting this error regularly, you should investigate the root cause. It might create a machine damage, or even a safety issue, which slightest possibility is not acceptable where human safety risk is involved. If you are getting errors regularly, please be safe, and do this. (Promise we will watch those videos as well ;). Take care.

I had a Mazda which would short out on a low battery or one which didn't have a good confection. It would set off the alarm, but in a way that was erratic and random. It happened to me once in the middle of the road when I had turned my car off to wait on a train. When I tried to turn it back on it went insane and started blowing the horn randomly and turning lights on and off randomly. Everyone around me probably thought I was the crazy one. It took a lot of research to figure out what happened and how to reset it. But I was eventually able to get it off the side of the road where I pushed it by following a reset process which was something like turn the switch on press the brake, turn it off, turn it on, turn it off, press the brake three times, open and close the door three times etc. I have no idea what the actual steps were but until I found those my car was just bricked because of a slightly low battery.

Get a BT OBD2 dongle. CHF 10 on ali. Then connect DDT4ALL on your laptop to it over BT. Reset anything you want. Also good for disabling seat belt alarm, start-stop feature and led light warnings.

Don’t know if it works on all cars but disconnecting the battery for a few minutes used to reset my error codes.

Laughs in pure mechanical car. Cries when trying to find parts. Seriously need to add a feature to allow a car to run regardless of error or at minimum allow the car to run x amount of distance after first detection. Found it very useful to randomize maintenance warnings.

I just watched an episode of Pine Hollow Auto Diagnostics where the CAN bus on a Mercedes was brought down by a rear windshield washer fluid leaking into the car shorting the signals causing a non-start, . Could you just sniff the reset packets coming from your brothers scanner? Interesting project thank you.

A very big thanks !!!!!!!!!!!!!! How to not make an ESP32 can bus reader/reseter. I think if you search the internet you can found easy how to reset (perhaps) because i think it is part of OBD2 standard command (but i'm not an expert just a mechanical and electronic hobbyst). I'm very impatient to see the second part.

hi, i was looking for the blue tooth phone charge controller project video, is it deleted ? can you please restore by any chance ?

One quick suggestion that you can try. There are very cheap dongles for ODBC 2 to Bluetooth or wireless. Most of them use the generic wirings. Then you better use a raspberry pi since audrino does not have these ports. 2nd suggestion is that you can get some free apps and use the dongle. I reset my 2013 bmw error messages using this dongle and app. But do not expect to read in-depth massaging.

I would record all the messages for 30 seconds, then I would record again and start the clear DTC command, then filter out just the new messages with either excel or SQL

The project sounds interesting, but probably a bit overkill for the task. But i'm not saying it's a bad thing 😊. Like other have been commenting the cheap 5€ bluetooth adapters works quite well. Finding the right software for PC or Android can be challenging. I think popular ones for android are “Car Scanner ELM OBD2” and “Torque Lite”. I think both can do DTC reset. There are also model specific pc software that can do many more things than basic software, but I don’t know what it would be for Volvos. One correction to your video. OBD2 is not exactly working on top of CAN-bus like you described. CAN-bus is one of the communication buses in the OBD2 interface, but there are also other for example K-line that can be used to talk with the ECU. It is possible that the scanner tool you are using is sending the reset signal through K-line instead of CAN-bus and that’s why you can not see it with the current setup.

There is only a small standard subset of can bus data thats the same for all makes of cars. The rest is all defined by the manufacturer and the details are not exposed to the public. They go to extreme measures to try and block access to the information, I know one manufacturer where the car has to be connected via the Internet back to them for diagnostic purposes, they get sent messages for what to check or change. ,looks like they don't even trust their own garages with being able to decode the data.

May be you can try a tester present of ECU on the bus, quite similar to i2c scanner, staring from 0x000 to 0xFFF ECU identifier, usually PCM has the common ECU ID... As Volvo on 2000 has also owned by Ford it is posible that exists another CAN bus on the vehicle at 125k speed, if you could see on the backside of the obd2 car connection twisted cables are CAN busses, check if there is only one bud or at least two: one at 500k and the other at 125k

Really hope you see this... I'm wanting to implement OBD2 along with posting sensor readings...but importantly also sending commands to automate AC, electric windows and interior lights...for a future overland LR defender build...please make a video on how to sniff and access sending command codes to CAN busto automate a vehicle with home assistant...

I use a couple obdlink mx+ and cx and use torque on my android phone. It will reset the cel and will communicate on the can high and low paths. You will most likely have to emulate elm327 and run software be it tied to your phone or laptop. I'm looking forward to this Btw the obdlink cx is bt le and doesn't work well with software that can't wake it up. Forscan refused to even see it. These use stn chips which will keep up with that canbus without a problem. The cheap elm327 are rarely even usable today.

I have a Bluetooth ODB2 device that cost $10 US, and a free Android app, that accomplishes this with also data logging and visualization. It works on my old Ford minivan up to my son's new Ford. It works across a lot of other makes and models, too. I can use the same device with the RPis, too.

Did you ever finish that product?

clearing all codes means you will have issues you wont know about and will cuase you pain in the long run!

Of course you don't care that you can get a volvo-specific odb2 scanner that allows you to view and clear the volvo specific codes. I had to buy one for my C30 project I did an engine swap on. It wasn't very expensive. But I've been wanting to do an odb2 scanner for a long time. On my 2003 Prius, it gets a check-engine light because the catalytic converter is missing a valve thingy that costs $1200, and no way I am going for that when another 2005 Prius cat works great but doesn't have it. So it would be great to have it clear this code as soon as it shows up, probably once a day. Or better yet, disable the check engine light on the dash, and instead have a device that only turns it on if ANYTHING ELSE comes up exdept that code. :)

Hi Andreas, Seems my previous comment has gone, probably due to github link, so I will try to put it once again. I was bit surprised that basic OBD2 command like Clear All DTCs does not work in the sandeepmistry's OBD2 library you tested and I think I found a bug in the code there. According to the OBD2 protocol there should be number of data bytes in the message, while in the clearAllStoredDTC() method there is send 0 as number of bytes. Please check line 714 of the OBD2 source file: CAN.write(0x00); // number of additional bytes CAN.write(0x04); // Mode / Service 4, for clearing DTC I would expect there 1 byte of data, so corrected code should be: CAN.write(0x01); // number of additional bytes CAN.write(0x04); // Mode / Service 4, for clearing DTC I haven't tested this, but you can try this fix if you want.

Perhaps it's better to get yourself a < $5 ELM327 OBD2 reader. There are several types of devices, wired, Wifi and bluetooth. With such a reader you can read OBD2 information yourself and you can reset error messages yourself. (on demand) The risk of automated resetting error messages is that you might miss important error messages, which may lead to serious (engine) damage. Some error messages can safely be ignored, others are meant to take appropriate actions immediately. (Unfortunately it cost me a repair of well over €2400 to understand)

The MOST frustrating thing with modern CANbus electronics in cars is this EXACT problem. I know that you do need a more expensive unit to do SOME of the more involved tests and diagnostics but my wife's VW Golf had a repeating non critical error that was becoming a real pain. It would only happen about once a fortnight originally but gradually got more frequent. I bought one of those cheap OBDII units off eBay for a few quid that works with the free app Torque (paid version supports some additional features). It worked great! Told me exactly what the problem code was, quick Google search to establish cause (faulty temp it said!) BUT, most importantly, it reset the fault code when requested. Fault eventually tracked to BOTH a faulty sensor AND a dodgy connection - something viewers should beware since such wire faults are always misreported (by the fault code description) as sensor faults - a potential money pit if an EXPENSIVELY OVERPRICED sensor is purchased and fails to fix the problem! I now have one permanently installed in both my car and my wife's. WELL worth the money!