Eddy555 Posted March 27, 2018 Report Share Posted March 27, 2018 So not long after I bought my 986 the ABS light would come on after a short amount of driving. Restarting the engine turned it off again. It got progressively worse until the ABS light stays on from ignition on. Over the weekend the battery charging light came on (the ABS light was turned off at this point which surprised me), and checking the charging voltage showed that the alternator wasn't delivering any charge. One exchange Bosch alternator later and the battery is charging correctly at 14.3V with the engine running. Cool. However the ABS light is back on. So I've just got my Durametric lead today and plugged that hoping to identify what fault code is causing the issue. However the ABS is showing no faults, but the instrument cluster module is showing the following error. Clearing the codes on either the ABS or the Instrument cluster doesn't turn off the light. 9111 PSM/ABS control unit I also noticed the ABS light flick off and back on again occasionally while I was connected with the Durametric. On my first run through with Durametric several modules had an over voltage supply fault code set - clearing these and they have not set again. However the ABS module seemed to stop communicating and I couldn't get any info back. Restarting the engine and I could read some info from the ABS module again. although still no codes. Has anyone else seen something similar or got any advice on what I could check? Link to comment Share on other sites More sharing options...
dazdman Posted March 28, 2018 Report Share Posted March 28, 2018 Strange had same issue. Codes cleared by Strasse and seems to be working ok again. Following your thread with interest. Strasse were scratching their heads too. Link to comment Share on other sites More sharing options...
Gutley Posted March 28, 2018 Report Share Posted March 28, 2018 One cause is the brake pedal switch failing. Easy enough to fix yourself if you are a contortionist. Whilst down there, you might want to swap the clutch pedal switch too as that can also fail in same way and cause Cruise Control to fail (if you have that) Link to comment Share on other sites More sharing options...
Eddy555 Posted March 28, 2018 Author Report Share Posted March 28, 2018 Cheers, the brake switch isn't that expensive and seems to be a common fault so I'll change that. Although the brake lights do come on when the pedal is switched it could be an inermittent fault that triggers the issue. Possibly. In Duramteric should you be able to read some Actual Values from the ABS as well? Like wheel speeds, brake pressure etc? There's no option on mine. Link to comment Share on other sites More sharing options...
Bike Loon Posted March 28, 2018 Report Share Posted March 28, 2018 Ive got a brand new brake light switch, can post it to you for £10 inc delivery if you like. I think its more likely to be an ABS wheel sensor fault myself Link to comment Share on other sites More sharing options...
Eddy555 Posted March 28, 2018 Author Report Share Posted March 28, 2018 11 minutes ago, Bike Loon said: Ive got a brand new brake light switch, can post it to you for £10 inc delivery if you like. I think its more likely to be an ABS wheel sensor fault myself That'd be great thanks. It's weird how I can't get any fault codes though and the speedo seems to be working fine, although I'm not sure how the logic works for converting the wheels speeds to vehicle speed for the dash. Link to comment Share on other sites More sharing options...
Bike Loon Posted March 28, 2018 Report Share Posted March 28, 2018 I had a faulty ABS sensor when I had my 986 and yeah the speedo dropped as soon as the light came on Link to comment Share on other sites More sharing options...
Eddy555 Posted March 28, 2018 Author Report Share Posted March 28, 2018 3 hours ago, Eddy555 said: In Duramteric should you be able to read some Actual Values from the ABS as well? Like wheel speeds, brake pressure etc? There's no option on mine. Answering my own question here, but according to the Durametric site you can't ready actual values from the ABS, so that's not a fault http://www.durametric.com/modelfeaturematrixv6.aspx#986 Link to comment Share on other sites More sharing options...
K.I.T.T. Posted March 28, 2018 Report Share Posted March 28, 2018 Not sure about durametric, but with PIWIS / similar Bosch tool used by my specialist picked up a fault with an ABS sensor on. When I bought mine, it exhibited similar symptoms to your car. When starting from cold, the ABS lamp would illuminate, but turning the ignition off and then restarting it would cause this to go away. It'd come on again upon restarting after leaving it resting for a while. As above, it was an ABS sensor. You do need to get a proper diagnostics tool on the car to narrow down the problem. The wiring to the sensor itself is a known weak point. Link to comment Share on other sites More sharing options...
Eddy555 Posted March 28, 2018 Author Report Share Posted March 28, 2018 Useful info, I'll have a look over the sensors when I get chance, and I'm booked to go to a Porsche specialist before too long so will see if they can shed more light on it. Link to comment Share on other sites More sharing options...
Eddy555 Posted March 30, 2018 Author Report Share Posted March 30, 2018 I've got the ABS light turned off. Seems to have been a faulty ABS wheel speed sensor, testing the resistance at the ABS ECU I could see the front right was all over the place where the other wheels were at 1600 Ohms. Changed it this morning (which was not trivial - see pic) and the light is now off. Thanks for all the help :-) Have to say I was a little surprised that Durametric couldn't pull any specific codes for this from the ABS. I'd have thought it would be capable but maybe I've just been spoilt from using BMW INPA. Link to comment Share on other sites More sharing options...
K.I.T.T. Posted March 30, 2018 Report Share Posted March 30, 2018 Glad to hear it was a relatively straightforward fix. As I mentioned earlier, I'm surprised Durametric wasn't more helpful as the PST / PIWIS / or whatever Bosch tool my specialist had identified a dodgy ABS sensor. Similar to your BMW tool, I'm used to VCDS for my VW, which is very comprehensive indeed. Is that 'wool' the copper wire from the old sensor?! I farmed the labour to replace mine out to a local indy who told me it was a PITA to get the old one out. Link to comment Share on other sites More sharing options...
Eddy555 Posted March 30, 2018 Author Report Share Posted March 30, 2018 Yep that's some quality copper wool. I can understand your indy saying it was a PITA. It was completely seized into the hub, so took some careful drilling, chiseling with a screwdriver to dig it out. Cleaned up the whole and the new one went in nicely. Link to comment Share on other sites More sharing options...
Bike Loon Posted March 30, 2018 Report Share Posted March 30, 2018 Glad you got it sorted out mate ! Link to comment Share on other sites More sharing options...
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