STEADY ABS Light with NO Codes
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Intermediate
Joined: Apr 2018
Posts: 25
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From: Chicago IL
STEADY ABS Light with NO Codes
Started my 1990 C4 yesterday and before I even took the car out of Park, the 'Service ABS' light came on. I pulled out the FSM and shorted the proper connection, but no codes were displayed; the light simply stays on, steady. The FSM mentions that there are five codes (all relays I believe) that won't show up without using a 'Tech 1' scanner.
Given that I have theoretically eliminated the codes that can be read with the on-board diag computer (and since I have the FSM), is there another way to find out what's causing the light? I know the ABS isn't working as I do not hear it perform its "self-check" (again, as the FSM indicates) when I first start rolling. Brake fluid levels are just below the max level, and the fuse for the ABS is good.
I would just prefer not to have to buy this "special" scanner, or take it into the shop for diag. Any thoughts would be appreciated. Thanks!
Given that I have theoretically eliminated the codes that can be read with the on-board diag computer (and since I have the FSM), is there another way to find out what's causing the light? I know the ABS isn't working as I do not hear it perform its "self-check" (again, as the FSM indicates) when I first start rolling. Brake fluid levels are just below the max level, and the fuse for the ABS is good.
I would just prefer not to have to buy this "special" scanner, or take it into the shop for diag. Any thoughts would be appreciated. Thanks!
Last edited by DefinitelyMiami; Jun 5, 2018 at 07:10 PM.
Safety Car
Joined: Aug 2013
Posts: 4,429
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From: Minneapolis Mn
I had an issue with mine and also don't have the tester. What I tried was rapping the relays on the abs unit (with the car off) with a plastic screwdriver handle then tried starting. It worked after rapping the relays. I then went out on ebay and found replacements based on the numbers off the 2 relays. Mine were used on a number of different brands of cars so look that way rather than for a Vette. Ones listed for Vettes were 4-6 times as high as the same ones for a MB or Porsche.
Good luck, hope it helps.
Good luck, hope it helps.
Last edited by hcbph; Jun 6, 2018 at 12:25 PM.
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Well you either need to pay a shop to diagnose the issue and then you complete the repair, buy the tech1 and diagnose and repair, or find somebody local on the forum and borrow their tech1 to diagnose. Without the tech1, you are in the dark.
My preference is to own the tool and not depend upon anybody else. If you are going to own this car, it is a wise investment to have a tech1.
My preference is to own the tool and not depend upon anybody else. If you are going to own this car, it is a wise investment to have a tech1.
Safety Car
Joined: Aug 2013
Posts: 4,429
Likes: 605
From: Minneapolis Mn
From what I read when I was diagnosing mine, the pump will cycle on startup even if one of the wheel sensors is bad. If I had to guess, I'd lay my nickel on the one with the silver cover on the top of the pump.
Like I said, abs light was on solid and the pump did not cycle. Couple of raps and the pump cycled a couple of startups. Replaced the relays after that and no issues since.
Thread Starter
Intermediate
Joined: Apr 2018
Posts: 25
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From: Chicago IL
I think this is the strongest indicator it's likely one of the relays is sticking like I ran into. Pull the well cover and give the relays a couple of raps with something like the plastic handle of a screwdriver, just has to be hard enough to shake them in case one is stuck. If the abs works even one cycle of the ignition after that then it's most likely your issue.
From what I read when I was diagnosing mine, the pump will cycle on startup even if one of the wheel sensors is bad. If I had to guess, I'd lay my nickel on the one with the silver cover on the top of the pump.
Like I said, abs light was on solid and the pump did not cycle. Couple of raps and the pump cycled a couple of startups. Replaced the relays after that and no issues since.
From what I read when I was diagnosing mine, the pump will cycle on startup even if one of the wheel sensors is bad. If I had to guess, I'd lay my nickel on the one with the silver cover on the top of the pump.
Like I said, abs light was on solid and the pump did not cycle. Couple of raps and the pump cycled a couple of startups. Replaced the relays after that and no issues since.
Safety Car
Joined: Aug 2013
Posts: 4,429
Likes: 605
From: Minneapolis Mn
Good to hear you are making progress.
Now I don't know if an 86 and a 90 use the same relays. Here's some info when I was researching mine, some of the different vehicles that used the same relays that were used in my 86.
ABS Relays
Update: Went back and started looking up some of the models
Module Relay 0332002171: BMW E30 ABS Anti Lock Brake Pump Relay 318is 318ic 325i 325is 325ic 325ix
Mercedes W126 W123 W107 W124 W201 relay 0332002171
0 332 002 171 | PORSCHE / AUDI / VW OEM ABS PUMP RELAY
Solenoid Relay 0332205003; BMW E30 Mercedes Corvette ABS Pump Breaking System Relay Bosch 0332205003
NEW Bosch Relay (ABS) 0332205003 BMW 34511154919
ABS SYSTEM RELAIS VOLVO 740 - 760 - 780 - 940 - 960 / BOSCH 0332205003
Possible alternative for 0332512006: 0332512007. That one has a skirt that would have to be trimmed, but first look appears it may be the same relay in a different housing.
I was just going against the Bosch numbers on them I wrote down from mine:
Module Relay: 0332512006 - Looks like there's another possible but would have to do a little trimming on it.
Pump Motor Relay: 0332002171
Solenoid Relay: 0332205003
Gives you an idea of what might be available. When I was doing mine I found one relay listed for a Vette for something like $90. I ended up finding both, one for MB and one for a Porsche and both ended up costing me around $25 used. When looking, go by the numbers off the relays, not based on the car and you'll find a whole lot more.
Now I don't know if an 86 and a 90 use the same relays. Here's some info when I was researching mine, some of the different vehicles that used the same relays that were used in my 86.
ABS Relays
Update: Went back and started looking up some of the models
Module Relay 0332002171: BMW E30 ABS Anti Lock Brake Pump Relay 318is 318ic 325i 325is 325ic 325ix
Mercedes W126 W123 W107 W124 W201 relay 0332002171
0 332 002 171 | PORSCHE / AUDI / VW OEM ABS PUMP RELAY
Solenoid Relay 0332205003; BMW E30 Mercedes Corvette ABS Pump Breaking System Relay Bosch 0332205003
NEW Bosch Relay (ABS) 0332205003 BMW 34511154919
ABS SYSTEM RELAIS VOLVO 740 - 760 - 780 - 940 - 960 / BOSCH 0332205003
Possible alternative for 0332512006: 0332512007. That one has a skirt that would have to be trimmed, but first look appears it may be the same relay in a different housing.
I was just going against the Bosch numbers on them I wrote down from mine:
Module Relay: 0332512006 - Looks like there's another possible but would have to do a little trimming on it.
Pump Motor Relay: 0332002171
Solenoid Relay: 0332205003
Gives you an idea of what might be available. When I was doing mine I found one relay listed for a Vette for something like $90. I ended up finding both, one for MB and one for a Porsche and both ended up costing me around $25 used. When looking, go by the numbers off the relays, not based on the car and you'll find a whole lot more.
