Service ABS and ASR Lights Came On

[Grizzly]

This spring I put new zo6 rims and D3s on my '92. Wanted new brakes because the old ones were so dirty and decided to flush the system with a power flusher.

Ok, that was more than 1,000 miles ago. I figured by now the brakes should be bedded so I hit them real hard just to see if everything was ok. It pulled down quick and straight but both lights came on. Turned off the engine and restarted and the lights were out. Lights stayed out for the next few days. This morning on the way to work they just came on.

Two things, first will driving it in this condition hurt anything other than those two systems aren't working? Secondly, any suggestions as to where to start? I don't have a code scanner yet, maybe now is the time.

Thanks..................Griz

[gmjunkie]

This spring I put new zo6 rims and D3s on my '92. Wanted new brakes because the old ones were so dirty and decided to flush the system with a power flusher.

Ok, that was more than 1,000 miles ago. I figured by now the brakes should be bedded so I hit them real hard just to see if everything was ok. It pulled down quick and straight but both lights came on. Turned off the engine and restarted and the lights were out. Lights stayed out for the next few days. This morning on the way to work they just came on.

Two things, first will driving it in this condition hurt anything other than those two systems aren't working? Secondly, any suggestions as to where to start? I don't have a code scanner yet, maybe now is the time.

Thanks..................Griz

Not all Scanner's will work on ABS and ASR !! Check all lines,Master cyl. and wheel cyl's for leak's!! a bad speed sencer can couse bouth lites to come on too!! bad relucter ring,Dirty relucter ring!! Sencer's and relucter ring get metal shaving's on them from Brake's!! And wont pick up sig!! junk!!

[Grizzly]

No leaks but the sensors not picking up the signal is interesting. Would it be reasonable to assume that since the ASR is on it is one of the rear sensors?

Maybe we're getting some where..............Thanks..

[gmjunkie]

No leaks but the sensors not picking up the signal is interesting. Would it be reasonable to assume that since the ASR is on it is one of the rear sensors?

Maybe we're getting some where..............Thanks..

That's where I'd Start!! junk!!

[hooks]

check fluid level in your reservoir--just a little low can cause this--my 93 had same problem--topped it off & no more lights

[Hrtbeat1]

GMJunkie has a good point about the wheel sensors.


There is a procedure for scanning the ABS computer for codes. If you ground pin "K" (I'm pretty sure this is the right one ... don't have my service manual with me but I'll verify later today) .... jumper between pins "A & K" on the ALDC, the ABS light will flash in a sequence ... these are the codes. It should start with 12 then it will go through all codes stored in the computer, each code will flash three times then it will go to the next. There is a specific procedure for clearing the codes also. If you have a service manual its in section 9 IIRC.

FYI you can also scan the SIR computer and the CCM. The CCM works in conjunction with the ECM with the CCM being the master so you can actually do both the ECM and CCM with the one test.

I'll get the correct pins for each of the tests when I get home. I know they are pins "G, H, & K" but can't remember which one is for which.

[Hrtbeat1]

OK its pin "H" so jumper pins "A & H" turn the ignition ON but don't start the car. After about 3 seconds the ABS light will start flashing once, pause, twice (12) it will flash this three times and then flash any stored codes repeating each three times. The manual says the system can store up to three different codes, or the same code three times if an intermittent were to occur.

Here are the codes from my '90 manual. They should be the same as GM didn't go to OBD II till '96.

12 Diagnostic System Operational

21 RF Wheel Sensor fault
22 RF Toothed Wheel Frequency error
25 LF Wheel Sensor fault
26 LF Toothed Wheel Frequency error

31 RR Wheel Sensor fault
32 RR Toothed Wheel Frequency error
35 LR Wheel Sensor fault
36 LR Toothed Wheel Frequency error

71 EBCM fault electronic brake control module
72 Serial Data Link fault
75 Lateral Accelerometer fault (Short to B+ or Ground, or Open Circuit)
76 Lateral Accelerometer fault (Signal Out of Range or Incorrect)


There are some codes that can only be read with a TECH 1 diagnostic computer (Im guessing Dealer) These deal with the Pump Motor, Solenoid Valves, and Relays. The good news is if any of these codes are set the ABS light will stay ON. So unless your light is always ON you can do the checks and any maintenance. Like Junkie said the little magnets pick up junk .... getting to them is a different story. The back ones you could probabally give em a shot of brake parts cleaner (use the little tube and SAFTEY GLASSES)

To clear any codes ground pin "H" turn the ignition to ON but don't start. After the ABS light starts flashing Unground "H" for at least 1 second then Re-Ground. This must be done Three times within 10 seconds. One of the good things about the system it does a built in test each time the ignition is ON and the vehicle speed is between 3 and 11 MPH. This is why a Road test is needed for any diagnostics of the system.

Hope this helps

[C4Tom]

Check fluid level in the resevoir. Mine was a tad bit too low and the same thing happened. Add a bit more fluid and see if that fixes it.

[c4cruiser]

Fluid level in the MC reservoir is critical for keeping the lights off. Only a 1/4" low will cause the lights to come on. The "FILL" line on the reservoir is pretty hard to see but it's just under the top of the reservoir. Fill to the line and your problem should be solved.

[Grizzly]

Fluid level in the MC reservoir is critical for keeping the lights off. Only a 1/4" low will cause the lights to come on. The "FILL" line on the reservoir is pretty hard to see but it's just under the top of the reservoir. Fill to the line and your problem should be solved.

Thanks all. Didn't realize the master cylinder was so critical. I'll do that first and see if I still get lights. Drove home tonight without a hitch......Griz

[guessguy]

3 of my lights come on after about 15 - 20 minutes of driving. Turn off the car, it goes away for another 15 minutes. I topped up the brake fluid, but the "Service ABS", "ASR OFF", and "SERVICE ASR" lights all come on. Could I have a brake line leak somewhere?