2005 Chevy Cavalier 2.4? Automatic Trac Light
I'll attach pictures in a few minutes from phone. Codes P0134 (02 sensor) & C1175 <PCM requested ETS to be disabled>. Haven't addressed the P0134 yet as complaint was Trac Light on intermittently. Trac light is off today. Test drove watching ABS data as assumed one was dropping out. ALL the wheel speeds will drop out but not at same time. They just glitch for a second or so. Seems to be more repeatable below 30 MPH and turning. Only scanner i have available is my AutoEnginuity. Found the battery voltage, both switched and "ignition" to ABS drop out to zero, but not exactly together. I haven't had time to do any visual inspection except looking through the wheels at nearly worn out front brake pads. Do these have ignition switch issues? No other symptoms I've noticed. Owner is 85, my landlord, so her info can be a little sketchy.
I would first fix what you know is broken. Many times, things like traction control, cruise control and remote start functions are disabled when the CEL is commanded on.
MIL light is NOT on. Only TRAC Light.
Clear codes pending and other and recheck
I was working in the dark. I'll verify the 02 operation first tomorrow. But the voltage dropping to zero in the ABS module indicates a problem to me.
An O2 sensor code will do nothing to the ABS, however on this car I have seen bad throttle bodies cause this issue. When the throttle body mess's up it sends a signal to the abs and traction control limiting power. I would first recommend using a better scan tool than the autoenginuity. I demo'd that for a while and had nothing but problems and it would not gather data fast enough to see glitches.
I have seen a code set or pending in ecm create all kinds of problems in abs or traction control modules . Trouble shot the code that you have first .
Tech tip from Identifix: The Trac Off light is on because the PCM cannot assist the Electronic Brake Traction Control Module (EBTCM) in a Traction Control Event because of the (P0134) DTC. It says diag the p0134 first. Just like the rest of you...I'll go stand in the corner.
Hi Gail: I can't say that I disagree with Albin but I'd be curious what happens to your Engine Run Time when the battery voltage drop outs occur. Also, what do you mean by battery voltage - switched vs. ignition? HTH, Guido
It show 2 battery voltage PIDS. One is "ignition" other is "switched". I'm assuming the ignition one is hot at all times. I'll look at the wiring diagram. Picture # 5 shows the description. But i don't really trust the AE software. It's pretty good on Powerstrokes. haven't used it much on anything else.
Hi Gail: I think that you picked up on where I was going with that. Obviously, B+ isn't switched. For you to show a loss of power at both circuits at the same time would require: a lack of integrity going to the fuse box, a lack of integrity at two separate circuits at (or after) the fuse box, or your scan tool is of dubious accuracy. Guido
As I agree that the PCM can shut down ABS system, a slow switching O2 sensor as show from your DTC picture will not cause that. Yes the O2 sensor is probably old and needs replace but I'm quite sure you'll still have the same problem with the ABS. About the only thing I have ever seen cause a PCM to deactivate an ABS system is a throttle body. I would be looking hard at your TPS sensor readings…
I would check p0134 and alternator with better scaner/ scope
C1275 is a hard code. Can't clear it. I'll try a global reset but am fairly certain that's not gonna help. My gut says I have an issue with ABS module.
I'm in agreement with the majority here that the P1134 needs to be addressed first as well. I too have used the Autoenginuity scan software in the past and would see ABS speed sensors drop out randomly ( Usually all of them during a long road test ) i learned to ignore them unless i was looking for issues in that area. The voltage issue you see , if repeatable, you can easily graph both values…
Awesome reply. Not sure how many watched my horrible video but the car currently has no driveability issue. No warning lights on. Even when driven and voltage to ABS drops, no warning light. After much research realize this is this generation of cars "stabilitrac" light which is a secondary indicator. Those were/are frequently throttle body/wiring related. This car has old school cable operated…
And to be clear, no longer at PEPBOYS.
Top sensor is one I installed several months ago. It definitely seemed to 'flatten out" at idle even though heater circuit was showing amp draw (.65ish). The new sensor, bottom, pulled slightly less amps (.45ish) but stayed active at idle. She says TRAC light would only come on at start up but would then occasionally go off while driving. So PCM is commanding light @ start up, then at some…