ABS TCS and BRAKE lights on dash with NO CODES

  • Thread starter Thread starter bighank
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bighank

Have ABS, TCS and BRAKE dash lights AFTER starting the vehicle. The green led in the TCS momentary switch is off, and pressing the switch will not turn on TCS. Fuses for ABS and TCS check out good. With ignition on and not started the warning lights are all off. Pulled both front wheels and disconnected sensors at wheels. Results: Both sensors read ABOUT 1080 OHMS (RIGHT IN THE MIDDLE OF GMs VALUES im Service Manual), and not shorted to ground. Resistance up the harness is about 40k ohms on both sides with no shorts to ground either (THERE IS NO VALUE GIVEN FOR RESISTANCE UP THE HARNESS TO THE EBCM).
With both sensors REMOVED the 3 dash lights come on IMMEDIATELY after turning on the ignition and stay on when you start the car. Replaced both sensor plugs and symptoms are as first stated ... lights off when ignitiion on but engine not running and then come on when engine is started.
Used a Toptak TP-300 scanner and got NO CODES WHATSOEVER.
Went to Advance Auto and used their new ACTRON scanner. Once again NO CODES WHATSOEVER. Do I have to go out and buy a Geniscan MaxScan VAG 405 scanner for $160 to read ABS codes? Not even sure that this scanner will read ABS codes for a GM vehicle. Description on www.alpha-bit.com leads me to believe that its enhanced functions relate to the proprietary protocol on VWs.

What do I do NEXT?
 
ABS TCS BRAKE lights UPDATE

Pulled ECBM and measured resistances to all wheel sensors. About 1080 ohms and no shorts to ground. Check Brake Relay operation and got 12 v to the ECBM connector and also to the soleniod fuse. Fuses all good. Removed battery and cleaned up both POS and NEG leads including terminal feeding engine mounted fuse box. After reassembling and reconnecting ECBM, turned on ignition. After bulb check the ABS, TCS, and BRAKE lights all remained OFF. Started the car. Lights still OFF with engine running. Applied the brake and all 3 lights come ON and stay on. Can't read the codes. What do you suggest next. Dont want to dump a bundle of cash into replacing ECBM, Modulator or solenoids if they are not defective.
 
Nobody knows anything about ABS or ECBM on here?!

No experts here. What good is this forum?:confused:
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Not real familiar with the ABS systems - sounds like you've been pretty thorough in checking and verifying. If the lamps are coming on, but there's no codes stored, would suspect a problem with the ABS computer.
 
I would suggest having a dealer check the system with the Tech II it is the only scanner capable of pulling accurate (detailed) ABS codes out of the EBCM I have repaired the systems but without the scanner there is no way to tell what the problem is for sure...
 
What year is your Montana? Ours is a 2006 SV6-we have those lights all the time and it never stored a code. Our dealership techs finally decided it was a left wheel bearing. We have had a lot of work done it since we got it in August. New tie rod ends, alternator, outside temperature sensor, various electrical problems fixed. Now we are getting a new left wheel bearing and a new DVD player. The bearing is on national back order, which tells you there is a problem if they are needing to replace that many. Our DVD player gets way too hot and won't work, so that's getting replaced. It's going to be practically brand new once we're done with it!!! We have friends that have the same year van as us and they had a problems with the ABS, TSC and Stabilitrac lights coming on and they had their left wheel bearing replaced and that fixed it. You might have your tech's check the left wheel bearing. Good Luck!!!
 
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