pestrada38

Abs light error code 77 left front solenoid circuit shorted to ground.

I had a brake light and abs inop light on since I bought the car in February.

I bought a used ecbm and the brake light is no longer on, still have the abs light on.

I replaced both front wheel hubs with SKF wheel hubs and replaced the rear differential sensor.

I have removed and cleaned all ground wires and replaced my 3rd brake light bulbs. The bulbs were working fine but I installed new ones anyway.

Scanned the car with scan 94/95 and I’m getting readings from both wheel hubs along with the Error code 77.

Sometimes the light comes on and sometimes it does not.

I have cleared the abs error code with scan94/95 but it does not take long before the abs inop light comes back on again.

Could I possibly have a defective wheel hub?

I am running out of options and my last resort is to take it to a shop where they can use other tools to troubleshoot it.

I would appreciate it if you all can share any information or guidance on this.

Thanks!

pestrada38

Sorry! I’m still getting familiar with the forum. I should have posted this under brakes!

Injuneer

Do you have access to the factory service manual? If not, available for free download, courtesy of GaryDoug.

https://www.mediafire.com/?40mfgeoe4ctti

I'll move the post for you. For future reference:

https://www.camaroz28.com/forums/lt1...nature-879835/

pestrada38

Thanks! After reviewing the service manuals It mentions to test (left front solenoid) Where is this located on the vehicle? See attachments.


Thanks,
Pest

Injuneer

In the 94 manual, look at the cross-section, Figure 1 on page 5E1-3. The solenoids are the two round discs on top of the ABS modulating unit, with the blue/white electrical connectors.

pestrada38

Thanks! I’ll look into it and keep you posted if this resolves my problem.

pestrada38

Thanks again for the information on this. Now the problem, finding a new solenoid. I’ve troubleshooted the issue as per the service manual and now it’s asking to replace the solenoid. Auto parts stores don’t carry them. My only resolution is buying a used abs pump from a salvage yard and then remove the solenoid from the salvage yard unit. Once replacing the solenoid I would then need to bleed the abs pump as well. Another task that I’ll need to tackle. Ugh!

pestrada38

Injuneer

95LT4Z28

i had a similar issue with a monte carlo i have. same on and off abs light. replaced same parts you did- same result. light stillon. turned out to be the wiring harness to the wheel.

pestrada38

BIG SHAFE

Just a thought, have you look at or cleaned the ABS sensors? Sometimes rust/debris will block the magnet.

95LT4Z28

i inspected the wiring by hand looking for any soft or hard spots. when i pointed the harness down i noticed a little water came out of the covering. when i cut the covering back i found a spot that had a little muck. when i cleaned that off the wires seemed a little soft there and a little fat a little further up. after i replaced the harness i cut the old one open and found the wires started to rot in one spot and in the fat spot the wires were oxidized . at first it would only happen in the winter on cold days or highway drives. im assuming the water that was trapped in the covering would freeze preventing communication with the hub. i deleted the abs in my 95 so i have parts if you need -- -al

Injuneer

When doing your trouble shooting for DTC 77, did you follow up on all 4 steps shown in the factory manual logic diagram (partial page shown in post #4)? Specifically, did you do the check on the resistance on EBCM harness connector terminal B1 to ground? Did you inspect the wiring and connectors between the EBCM and the solenoid? Did you see the bottom of the page where the logic diagram concludes "Replace EBCM"?

The other possible conclusion at the bottom of the logic diagram is that there is an intermittent problem, that may be covered in the "Diagnostic Aids" on the facing page (page 5E1-140), although part of that requires a Tech 1.

pestrada38