Somewhat ungracefully, I demonstrate on a 2006 Chevrolet Impala the 'bi-directional' control of the radiator fans using nothing but an outdated android, a handful of data and a $21 obd2 dongle (not even an authentic ELM327).
Notice, in the video, the command '3E' (tool present) must be continually sent or the control will be lost.
(pretty much all numbers below are hex, by the way)
Here's the data, some bi-directional info on this vehicle (chevy, impala, 2006, 3.9L, 9C3) and likely some others.
Body Controller ECU is 241
Engine Controller ECU is 7E0
Commands you send will only remain for a few seconds, unless the car receives the 'tool present' command which is simply 3E repeatedly sent to header 7E0 - and you have a second or so to send the command...and then the commanded state will remain (at least for the radiator ) that's why I keep touching the send button - to send that 'tool present' message.
Here are the bidirectional commands I've discovered so far. Notice how the bit values are laid out when translated from the hex. You can see the 0 vs 1 values explicitly.
Radiator Fans:
Turn Fan1 On (AE20000000C000) header:7E0
C0 = 1100 0000 as bits
Turn Fan1 and 2 On (AE20000000A000) header: 7E0
A0 = 1010 0000 as bits
Turn Fans Off (AE200000008000) header:7E0
80 = 1000 0000 as bits
BE VERY CAREFUL WITH ANY MODE $3B COMMANDS
MODE $3B is a MEMORY WRITE mode. (likely how I reset my crankshaft calibration)
Set Oil Life (3B6DXX) header: 7E0 note this is mode $3B
where XX is (00 - FF), or 0 to 255 in regular decimal numbers (hex avoids 3 columns)
S0, the commands to header/canid 7E0 to set oil life would be
3B6D00 = 0%
3B6D81 = 50%
3B6DFF = 100%
Oh yeah, to read...(remember doing that) oil life the pid is (1A6D) header:7E0
I'm thinking mode $1A is a GM 'read' mode concurrent with $3B write mode - here $6D is the oil life pid value. (We read and write to pid $6D)
BCM (body control module) ECU 241 - still investigating
dome light off
(AE1A0100000000) header:241
What's that app? It's Android. I wrote it. And, you can get it here....remember, it's a hack thing.
CAN App Download Page:
www.thoughtpil...