Great to hear! Your Welcome

Dead on bud! Good stuff..happened to mine...no cruise control Ironically..only changed valve cause of air leak.. Viola!!..my cruise started working!!

Glad it helped

You are welcome. It is a strange problem that a local dealer could not figure out. They replaced a couple of sensors which didn't fix it. I decided to diagnose and fix it myself. I did alot of testing to figure out what was really going on. and decided to share this because it is a hard to diagnose issue. I can't believe a ABS valve could fail in a way to send air back into the truck the wrong way which slightly applies the brake. After this happened on another truck in my fleet I knew it was not just a one truck weird issue and it could possibly happen to others.

Thanks

It took me only a day to figure it out when even the dealer had no idea what was going on changing a sensor that wasn't even throwing a code

Was it the ABS valve? I also have a 2014 MX-13 and having same issues. I notice my loss of power is more noticeable going up steep hills.

Having some problems now

****EDIT*** My foot service break is leaking air. Loss of power while driving or little to no acceleration. It’s the exact same issue as this video.

You are welcome

You are welcome

The issue on this one is a 2019. Not sure what other years were affected

It is affecting my 2016 Pet 587 same engine same ABS valve. I honestly burned thru thousands and then I found this video. God Bless You.

How did you get this fixed. I have a 2011 t660.

A ABS light will not make the truck reduce power. Sounds like the truck may be gong into derate. However when the front ABS valve was leaking back which lightly applied the brakes the throttle would completely drop out. Before replacing expensive components I always plug into the the MX so see the codes. Some are not always clear cut but can give clues as to what is going on. The valve seats were a repair campaign by Paccar which was for oil consumption. Without seeing if there are any logged codes if would be difficult to guide you.

I have the same exact problem as you but I have no codes at all. Truck has done it since I got it at 10k miles, it'll drop power feels like 10% derate or something under WOT for a few seconds and then back to full power 35psi boost only to drop back down to 25-28. Does that over and over all day. Replaced all filters turbo speed sensor also was a TSB for it. Have you had any luck?

@@DHunt-dt9hm just got the same problem im around 25psi boost on the turbo no codes nothing just started after I felt like I wasn't getting enough power so I started looking at my gauges better while driving n noticed wasn't getting enough boost idk wat the problem is

@@DHunt-dt9hm did you ever figure out your problem? I’m having this issue and would appreciate your help

Did you ever figure out this issue? I need your help.

Paccar not Oscar

After removing the turbo actuator it needs to be reinstalled by laptop and then calibrated with a laptop. The injector 5 issue could still be a separate issue and in the injector harness. I would swap out injector 5 and injector 4 to see if the problem moves to a different cylinder. If not you then need to run a compression test on a laptop to make sure the cylinder is good. If not you could have a bad cam or cylinder. If good replace the injector harness.

I’m having the same problem, how did you get yours fixed. Thanks

Yes. There is a small positive wire in the battery box. It has a small plug on it. Sometimes this plug corrodes or loses contact. We have been cutting them out and splicing them together with connectors. Make sure to use heat shrink over the connectors. Also we have found bad grounds in the past. There is a ground on the back side of the battery box that is a pain to get to but seen rubbing issues there. Also take off each battery jumper and do a tug test. The KW jumper cables are known for rotting on the inside but you wouldn't know it unless you remove them from the battery and try to pull them apart. This should get you started.

@@Dakman Thanks a lot for the response! Started today, but I did not found any small positive wire inside. Or you talking about positive cable which has kind of a tail connected to it? Could not find ground wire at all, inspected under the truck, but no wiring attached somewhere behind the batt box. Tug test done, nothing found. After I put everything together truck started, run 5 min and shut off with "transmission/cruse/def blinking" and won't start anymore at all :(((

The best way to see if the valve is the issue is to use two ways of testing that I came up with. First test requires a application gauge. Drive the truck and watch the brake application gsuge. If it climbs up to 2 to 5 lbs that front brake ABS valve is bad and leaking backwards. If you don't have a application gauge. Take a pair of pinch off pliers and start to pinch off hoses on the foot valve. I believe when I pinched off the one green line only the front brakes applied. When the front ABS valve behind the bumper goes bad it applies only the front brakes because it bleeds air backwards. Next the ECM sees the brakes are applied because the bleed back also engages the brake light switch the Engine ECM is programed to reduce engine power so you don't burn up the brakes

Much appreciated

Yep we had this same issue. It was the pins in the plug for the level sensor. You will need to buy the plug housing and pins separately. They don't sell pigtails. Cut off the old plug and install the new pins with the correct crimper then install into the plug.

@@Dakman sent it to mechanic and sadly decided to to oil change with it he tried to fix the problem,, and of course he didn't,,, went to the shop found my truck nocking engine,,

Sounds like the front ABS modulating valve is leaking back. You telling me you have 5 psi on the application gauge proves this. 5 psi is enough to turn the brake lights on. Once the ECM sees the brakes are applied it reduces power significantly. It's programed to do this so you don't burn up the brakes

@@Dakman yes Sir, thank you for your video, we found the leak but we can't find the part, is a small rubber that on the top of metal inside that front valve, looks like not draining tanks for long time can cause it by water.

Unplugging the switch will not help. All of the lights on a T680 go through a computer called a CECU or Cab Electronic Control Unit. The only other thing you can do for now is out the fuse from the fuse box under the hood and on the left side is a fuse box on the fire wall. You could still have a bad switch but unplugging it will still make the lights come on. There is a diagnostic software called ESA in which you can read CECU codes. Switches no longer carry current to make things work. They carry CAN messages to the CECU and it is what turns power on and off. Trucks are getting too much like cars. Can't wait to retire.

I got 32 years of working on diesel diesel trucks. I'm Cummins certified, Volvo Master Certified, licensed NJ Diesel Emissions Inspector, CDL A Licensed. I just don't like making truck repair videos that much. I normally had enough after a day of working on them lol.

Is advised you really know trucks. Your honest opinion really matters to me. On a 2015, 2016 trucks what should I get. DD15? Volvo? Cummins or paccar?

I'm Cummins Certified, a Master Volvo Tech and do work on Paccar. MX13 as well as the Detroit DDE15. It's like they each have their own set of problems. None of them are problem free when it comes to the emissions components. Most of the failed parts on each are expensive. So the first thing you need to ask who is your closest dealer. Getting the parts for your truck is key. Next you will need to put away at least $20,000 in a separate truck account for repairs. When you use it put it back. On the 2015 to 2016 Cummins ISX the fuel injectors fail and the high pressure fuel pump fails which also can fill the engine with metal. If you buy a Cummins invest in a oil sample at every oil change. On the Volvo the same year you can't seem to keep sensors in them. The Soot sensor, NOx Sensor and Airfuel purge valves fail constantly. On the DDE15 same year their DEF system design is crappy. They have constant issues with the screens in the DEF pumps clogging and the DEF spray nozzle seems to fail alot. The Paccar MX13 has issues with the BPV or Back Pressure Valve which is what creates the heat for a regen but when it fails there is not enough heat for a regen. Also the DPF filters are smaller on the Paccar so they can take less abuse. The DPF filters can get fused cells easily and make it useless costing you $4,000 to replace. Nothing is problem free. Go find a glider kit. Those don't have all of the junk emissions system that do nothing but cause issues, down time and money.

@@Dakman wow, you really know trucks.. thank you. 🙏

Nope. The issue I outlined in this video will not turn on a ABS light

@@Dakman ok I have a 2010 kenworth t660 automatic Cummins engine and it doesn’t have a engine light or abs light but has no throttle response sometimes at a traffic light or when I make a complete stop , cut it off and restart and it has throttle again, I’ve replaced the throttle petal sensor and still have the same problem could it be that abs module your talking about?

Did you replace the thermostat? I have seen them where they slightly stick open and don't close all the way. This is a big issue on the Cummins ISX as well with around 500,000 miles or more I found. Replaced a ton of those that would not close all the way.

@@Dakman Not yet because something might be causing coolant temp to run weird. few things seen after i made a comment. *coolant is getting darker, no visible leaks on gasket/seal area. *coolant temp drops faster while using engine brake *noticeable sooth buildup around oil cooler and Crankcase centri. After running 6K miles. no check engine light no dramatic decrease in Fuel econony.

@@johnrusselllubo change your thermostats.. Mine was identical to yours...2 stats in....all better!

Yeah the DEF level sensor is bad. Had this happen on my own fleet. You have to drop the DEF tank to replace the sensor which is a pain. You need to drain the coolant as well since the DEF level sensor is heated by coolant. Careful the coolant lines are fragile to remove. Not one of my favorite jobs.

@@Dakman you can clamp the coolant lines and pull them off the def tank, and just roll the tank and get the old sensor out and new one in, an hour, 1.5hour job at most

Yes, if this is really your problem then disconnect the brake light switch. But I warn you it's not easy to get to.

You can only remove the TPMS monitoring system for the tire pressures. You can't remove the antilock brake system part because it's part of the safety system and it's mandated to have that system by law.

Depends on the mileage. After 500,000 miles the maintenance costs gets very expensive. Ask for maintenance records when the DPF filters were cleaned or replaced. Most people dump their regen trucks when they need serious money dumped into them.

Do yourself a favor and pass on that one bud. Those trucks are nightmares. I worked at a kenworth dealership for a little over a year and hated when those things came in. They are ALL plagued with electrical problems

If the wrench light is on this issue won't be the one you have. If both fuel filters are good more than likely the wrench light is indicating a issue with the DPF system. If the red light in the DEF Gauge is on than it indicates that you have a DEF code. More than likely the engine could be in derate mode and has a code causing it.

@@Dakman it’s also deleted,,the gas pedal has been sticky as well lately,,suppose it might be the switch under the gas pedal good sir?

@@Dakman this is a company truck I’m driving but my wife and I are in the market for a good strong dependable dump bed,,what model do you see tore up the least? This Kenworth Paccar is a constant something I’ve been driving it 3 years

Wow. How can someone have a truck for two months and still haven't found the problem. Well tell us in a comment what the problem is maybe we can help figure it out

Well long story short, we have replaced all injectors, new fuel pump, new lift pump, new turbo. Ran approximately 15 different tunes thru it, and it still has a stutter around 1750 rpms. But it only does it in the top three gears, low side of transmission it’s perfect.also once your up in the top gears it has a hard time accelerating past 1600 rpm. The truck is deleted and has been from almost day one, it currently has approximately 700k on it. Any help would be appreciated this problem has cost us thousands of dollars and we are on the verge of losing everything.

Hey Robert were you able to fix your truck im having the same issue and my mechanic cant figure it out

Did you ever figure out the problem? I’m having issues with mine again