bobdec

Has any one seen this ? My ABS dash indicator goes on 2 seconds-then off after ignition is turned on so the initial testing is OK, and the brake lamp does the same. But once I start driving over 10 MPH the ABS indicator comes on and stays on until my speed drops below 10 MPH, then it goes off. It's only ABS, the brake lite does not come on and actual braking works OK . I flashed the ABS codes by shorting pins A & H in the ALDL cable connector and the ABS lite continually flashes a code 13 which is not listed anywhere. I think I read somewhere the code 12 or 13 is normal with no error codes, but I can't find this written anywhere.
I spend a lot of time over on the LT1 and OBD1 tuning forums with my other vehicle a modified 1994 Z24, but documentation for the G20 is pretty slim compared to the F-body. I got desperate and paid for an online service manual subscription for the G20, it doesn't list code 13 or even show an ABS lamp in the dash.
My name is Bob, any ideas are welcomed...Vehicle is a 1995 G20 Conversion, with 5.7L gas engine

Mick

I have seen this on a few vehicles , and it's usually a wheel speed sensor dropping out as the speed increases.
A road test with a scanner connected will usually tell which one it is.
As long as the sensor reads wrong , the failure light will remain on , and turn off as the sensor resumes proper readings.
Pretty common , most shops will find it quick and the cost isn't too bad.
Mick

bobdec

I may have to do that..I can put up with the ABS lite, but the when the PCM sees the ABS failure it disables the cruise control. The van is a long haul conversion van we use on vacations and cruise control is one thing I want to function..

bobdec

Just an update.. on Saturday I made an appointment to leave it off on Monday. Driving around about an hour Sunday the ABS lite went off. Left off the car Monday, they kept it two days and drove it around twice... NO ABS indicator. Man they were real nice, didn't charge for their time, told me to bring it back when lite comes back on..They said this vehicle does not store the codes after ignition is turned off, that sounds weird. They said if lite comes on drive it in and don't shut off ignition so they can scan it ... I know the PCM stores codes forever unless battery power is disconnected, is the ABS different ?? Today is Friday, so far no lite. I know it will come back at an inopportune time, keeping my fingers crossed.

bobdec

Latest update.. it's been a month and now the ABS indicator only comes on about 50% of the time just after starting out, it stays on 10-15 seconds and goes off. Once or twice it's stayed on for about 1-2 miles before going off. I'm ready to start shotgunning parts and replace the front speed sensors. Don't think it's the rear as the VSS feeds the speed buffer and then the output feeds the speedometer and the ABS. Never see any speedo problems when ABS lite is on. Been looking at parts sites for the front ABS sensors, can't find any for the '95 G20 Sportvan, are they a dealer only item ??

UKG20dude

Hiya!

Looks like we may have some problems in common. I am hoping to take delivery this weekend. Maybe we can chat in the future? I think that my diagnostics are OBD1 though.

cheers, Darius