Need Help - Traction, DSC, TPMS, ABS Light Flashing Diagnosis

[mimarcos]

Hi there,

So I'm trying to diagnose an issue and figure out what I should order to try and DIY resolve the issue. After my last Watkins Glen weekend (2:17, would have been 2:15 if I didn't get denied a very obvious point by), I noticed what I thought at the time was a flash of the something on the dash but then just wrote it off as the DSC light that was lit since I had it, well, off.

Before I even got out of the paddock area, it started. The issues came and went during the entire drive home, very periodically, with worse ones happening near the very end of the drive.

• Traction, DSC, TMPS, and ABS would all light for < 1 second
• AUX input - and all audio - would cut out for the duration, resuming immediately after
• Near the end of the drive the infotainment screen would go dark and come right back.
• Near the end of the drive (on my street, actually) I noticed that something felt weird. Not a misfire, but maybe a barely perceptible dip in power

After the event I looked up the symptoms and I was pointed to one of 3 potential problems:

• Steering input sensor decided to take a permanent nap
• ABS Pump decided to kick it
• ABS Sensor(s) malfunctioning

But at that point, I knew I needed to bleed the brakes, as there was definitely some boilage (and.. wow.. there was - side question for those reading all the way through - I dunno if I'm doing something wrong here but with RE-71RS and HT-10 pads, I was absolutely cooking Motul 600. Going Castrol SRF but it seemed... excessive). After that went for a 30 minute ride, no issues.

No driving since then, took it out today and on the way home, the symptoms all came back 3 times in maybe 5m. Headed over to a mechanic to read codes (I have a BLE code reader but it's a little sketchy when it comes to actually reading codes). He didn't tell me exactly what the problem was, and I only saw a few of the codes, but they were all some form of "undervolt." On the drive back from the shop, I wasn't sure I was going to make it home - they were flickering on and off consistently, infotainment going crazy, and some ever-so-slightly more noticeable power dips.

Which led me to believe what it is: the alternator is on its way out. Before I make an impulsive maintenance item purchase, does this diagnosis seem reasonable based on the symptoms? Any chance it could be the battery (replaced < 2y ago)? Something else I hadn't considered?

Side note - I did put a crappy multimeter on the terminals, was getting 12.6 from the battery and 14.2, dipping to low 13.2 ish when the revs vacillated a little below the usual 850 or so at idle.

If I have any luck pulling codes tonight I'll post them, and if no one replies I'll post any updates I have. I haven't seen any other posts complaining about those dash lamps flickering on/off (except for one post https://www.zpost.com/forums/showthread.php?t=1608649), most of these issues seem to have the lamps persistently illuminated.

[mimarcos]

https://www.zpost.com/forums/showthread.php?t=1021920

Did actually find a bit more... sounds like I'm circling the right answer but that it might be the voltage regulator, and replacing alternator should solve the problem (especially since I can't quite seem to find the regulator as a separate part). Reasonably inexpensive from FCPEuro, will definitely be giving that a shot.

[Reborn_]

I had similar symptoms. Alternator swap took care of it. I would start there.

I think you can find the voltage regulator separately on ebay - but my logic was that since I was doing the job, I might as well put a fresh alternator in while I'm at it.

[mimarcos]

Just finished the alternator replacement tonight and happy to report that certainly took care of the problem did the idler pulley while I was in there. Seemed fine but meh had the bolt off. Was fun, first mechanical problem I’ve diagnosed and solved on my own!

Off to Lime Rock in 3 weeks!