ABS/PSM lights on, but no Durametric code?

The ABS and "TC OFF" lights on my '99 C2 are on. As also reported in this RL post , my Durametric says there are no codes in the ABS/PSM module. I was hoping to get a clue as to what may be wrong -- how can the lights be on, but there not be a code? The Durametric seems to be communicating with the ABS/PSM module, because the traction warning light on the instrument cluster, and the TC OFF light on the center console both flash when I check for codes. (A bit more context: Car drives, brakes, handles completely normal as far as I can tell, other than no ABS/TC. Speedo reads 0 though regardless of actual speed, although the ABS/PSM lights came on before that happened. Something creaks in the front left suspension but has done for a long time and my mechanic can't figure it out even though shocks, bushes and control arms have all been replaced.)

U probably have a bad abs wheel sensor or harness.

That would make sense, thanks! But doesn't the ABS module have codes to indicate which sensor is bad?

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it should. Usually when the connector for the Speed sensor goes bad, you will also get the brakes pads ware warning light. If you �clear all codes� will the lights go off?

Has anyone been able to get ABS related codes with the Durametric?? No brake wear light. The ABS/TC lights are definitely on again after clearing all codes -- but I am not 100% confident if they were off initially when starting the car but then came on after moving, or if they just stayed on.

happened to me when my ignition switch was going bad

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Interesting, thanks! I may end up replacing it just because I've heard other reports of the ignition switch causing trouble eventually. If this turns out to be the cause, would that explain why Durametric sees no codes? I'm still confused about that, I want to believe that if the ABS light is on there is a cause that can be read out...!

Pull codes from the instrument cluster too. You may find a "no communication with ABS/PSM" code.

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Hm, now that you mention it, I do believe the durametric would in fact read and clear the codes when they were caused by the ignition switch.

Did you remove the air box recently? If so, check that the MAF wire is firmly seated. Believe it or not, that will trigger an ABS/PSM warning light. Ask me how I know.

So in 7 years with this wonderful car I've had 3 PSM/ABS light faults that I had diagnosed each time without code reader; 1: Steering angle sensor. This is actually a long story but to make it short the car was out of alignment when I bought it. I had to drive for about 60 seconds with a crooked wheel and then they would light up - cleared with ignition off/on. 2: Wheel speed sensor. Did not get plugged back in after #1 was fixed. These lit up as soon as the vehicle was in motion. 3: MAF sensor not firmly seated as stated above. This lit up with the car turning on. So the condition in which the light turns on could be a clue for you which part is causing the light to illuminate. Do you have to move the car or does it turn on right away?

I think key to your troubleshooting is 0 on the speedometer. One of the wheel sensors is bad or disconnected. IMHO

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Or the ABS isn't talking to the instrument cluster anymore.

Lots of great suggestions -- thank you all! A couple of updates: The ABS/TC OFF lights stay on when starting the car, i.e. the car does not need to be in motion for them to turn on. As it happens, I did remove the airbox not too long ago to change the air filter! So I unplugged the MAF, applied electrical contact cleaner, let it dry, and plugged it back in, making sure to press it in fully. No change. I measured the voltage from the MAF at idle, 1.3V, which is a healthy reading as far as I know. My car is a '99, I believe the early clusters don't store codes, and Durametric doesn't seem to have an option to display them for me. I did note while Durametric says there are no fault codes in the ABS/PSM module, it doesn't report the details of the module, like the serial number or some other identifier. I wonder if this means that you're right and there is no communication with it. I agree, if the speedo is showing 0 (intermittently), that does seem to indicate a sensor issue. With no info from the ABS module, sounds like I have no other option but to try replacing the wheel sensor on a random wheel and seeing if the issue is fixed??

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Check the ABS Wiring connector. Mine came loose at one point and had the same issue.

Have you recently replaced any lights with LED items? If so, try swapping back or checking if they need a different resistor. It's also worth checking the ABS reluctor rings, these can rust with age & cause issues. These links have more details, which may help: http://911uk.com/viewtopic.php?t=149234 http://911uk.com/viewtopic.php?t=149574

If you can't make it better, try making it worse. Intentionally disconnect each wheel speed sensor in turn and see if you get a code. If you do get codes at all 4 wheel speed sensors when disconnected, that implies all four wheel speed sensors are working when properly plugged in. I don't think that is the problem. The ABS will send the speed to the cluster even if a wheel speed sensor is not working. The suggestion to inspect the ABS unit plug is a good one.

It also may be the abs modual. They do fail on sometimes. There r a couple companies that can test them out.

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that was exactly my case. i replaced or tested everything listed in this thread. I ended up replacing the module. got a used one with the same part number from eBay and it worked. No need to program or anything like it. here is a picture of the one I removed.

Update: I decided to read the FSM. It explains that if the ABS /TC MIL is on even though no fault is stored, a possible cause is that a mechanical switch in the ABS control module connector is not working. The purpose of this switch is to trigger the ABS MIL if the connector is not plugged in. It's the little switch indicated by the arrows: To test if this is the problem, I unplugged the connector and manually clamped this switch closed with locking pliers. Started the car, no ABS/TC light . Progress! However, I'm still stuck: I can't figure out why the switch won't close when the connector is plugged in normally. Nothing looks bent. I applied contact cleaner/lubricant (Bilt Hamber Ferrosol). The plastic pin on the mating connector on the ABS module whose job in life it is to depress this switch looks perfectly intact. I'm reluctant to start bending or soldering things, because I don't want to accidentally destroy the connector. Any ideas for what the fix is here?

Ugh, so I'm still struggling with this. What I know so far: 1) ABS connector unplugged but mechanical pin blocked from shorting telltale pins to ground (see picture below, I used a small piece of plastic, red arrow): ABS/TC lights off until I start driving. This is expected behavior: the piece of plastic should fool the instrument cluster into thinking the ABS connector is plugged in. 2) ABS connector unplugged but not blocking mechanical pin : ABS/TC lights on (don't even need to start the car to see, when starting the car both lights stay on, don't need to move). This is also expected: the cluster can now see that the connector is not plugged in 3) ABS connector plugged in but mechanical pin blocked from shorting to ground: ABS/TC lights on ??? What's the difference between 1) and 3)?

The bit of plastic in the ABS connector is broken off? Perhaps check continuity of those wires with the connector plugged into the ABS and see if they are actually being held apart. You will probably need to take the backshell off the plug to do this.

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Thanks for helping to think through this! Nope, it's there, looks completely unharmed. It's actually hard to imagine that it wouldn't do what it's supposed to when the connector is plugged in. But it's a good idea to verify this if I can -- I'll try to get the backshell off. I do think that the MacGyvered piece that I put in the connector (picture above) is doing what the factory bit of plastic is designed to do. So even if the factory mechanism for checking the connector is plugged in is somehow failing, the piece I added should accomplish that (as it does when the connector is not actually plugged in). So maybe blaming the mechanical connection in the connector is a red herring. But the ONLY alternative explaination for an ABS MIL light with no fault stored that's given in the FSM, a "missing terminal 61 signal" requires the engine to be running. I noticed the ABS MIL is on even when the engine is not running.. so that doesn't seem to be it.

Anyone selling a 40-AE please msg me.

I have both ABS and PSM failure warnings when I start the car (2002 C2). I have not been able to get them to you out. I have removed and checked the wheel speed sensors (they all pulse when putting a metallic piece up to the front of the sensor), reluctor rings all appear clean and intact, ABS wiring plug looks good, changed brake light switch with a known good one from another car (2002 C4 Cab). I checked the MAF and it is reading mass flow and 1.3v at isle according to my Durametric. Durametric shows no fault codes for engine and Instrument cluster, but does not have any folders for ABS or PSM. How do you check for a possible short in a wheel speed sensor, the wiring appears to be good. Next step may be to pull the ABS unit and send it out for testing. I am hoping someone else may have run into this and have some additional suggestions for troubleshooting this issue. Thanks to all for any help. Mark

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So every time you drive you get ABS/PSM warnings but durametric can't see them? Could be caused by a faulty alignment? When did you last have a 4 wheel alignment? When you installed the brake pedal position sensor, did you depress the plunger all the way? Was in a brand new part? Did you have to depress the brake pedal to get the pedal sensor in? Those brake pedal sensors are very easy to break while installing if you ham fist them. You don't want the plunger to get all the way depressed.

Yes, the lights come on and stay on at all times. Durametric does not show any faults. I pulled the brake light switch from my other car, it was functioning correctly in the other car. I have tested the brake light switch and it functions correctly for the brake lights. I plugged it into the bracket but I not depress the brake pedal. I have not had a 4 wheel alignment. I bought the car without an engine and have installed an engine and am working thru getting the car driveable. Thanks for the suggestions and comments Mark

Have u checked thw steering angle sensor yet? The durametric should be able to tell u what it is and if its functioning.

Durametric can't read steering angle sensor.

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I would get an alignment just to rule that out. When I put in new tie rod ends my car was exhibiting the same behavior and as soon as I got an alignment the lights stayed off.

Will get alignment checked next thanks

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I had commented back in July as well but based on this piece of information I do not suspect your steering angle sensor and this is because I lived through the PSM/ABS light due to bad alignment (car goes straight - steering wheel goes 45 degrees to the right,) and the light would clear every time I turned the car off. In fact I'd have to drive about 1/4 mile in a straight line with the wheel cocked off to the side before the warning lights illuminated in the first place. If I coincidentally did a lot of turning before going in a straight line - it would take longer for the error to pop up. If the trip was short enough it would not come on at all... Just food for thought before you go on another goose chase.

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Are you saying that Durametric does not communicate with ABS/PSM module?? If so , that is your source/clue.... Durametric or any high end Tester ( PIWIS) should be able to communicate with the ABS/PSM module ...I would try another tester and/or test the power source to the ABS/PSM module....( fuse B9 ?) The tester has to communicate with the ABS/PSM module to be able to extract any fault codes...

I think you may need to tick the checkbox to select which ABS is installed. You can tick ABS or ABS/PSM. If you don't tick one or the other box Durametric does not even search for the ABS module.

Thanks Skip, will check fuse tomorrow morning. Thanks prf. I will look for checkbox on my Durametric

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To be clear they stay on when you start the car? If they stay on without moving the car it�s not the alignment.

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This

Checked the fuse, B9 is good

lights come on at startup or only when the vehicle begins to move?

Lights come on when key is turned on and never go out until key is switched off. Car runs and drives fine but I csan’t tell if ABS or PSM are working.