ABS fault, then limp mode

[andrewwynn]

When you got/get limp mode so you get the gear icon on the dash?

[Bdc101]

All the codes your car is throwing are typical except the first one.



Fuel trim exceeded has been thrown on my car for years. I am slowly working on it but I believe they are usually caused by slowly-failing MAFs. The car runs fine with it, just might not be getting peak mileage.



The idle control valve -- does your car die when coming to a stop sign or putting it in neutral? If not, this isn't a worry yet. Reset it and if it comes back, take it out and clean it with brakleen. It will eventually need to be replaced if your car starts dying at stop signs and cleaning doesn't fix it.



AUC sensor: this just turns the HVAC to recirculation if it senses stinky diesel fumes outside the car. They have all broken by now, I think. First world problems.



Oil level sensor: just measures the oil level. If you check your oil level like any other car you won't have any problem.



Central locking: this code may have been thrown if you replaced a window regulator. Reset it. If it comes back, it isn't an issue unless door locks or windows don't work.



Can't help with the limp mode, but good luck!!

[Salty B.]

Thx for the info! Idle is fine and smooth. Car starts instantly. Sounds like the others I don’t need to worry about. I’ll clean the idle valve when I get home.

When the ABS fault happens the triangle with the ! in it and looping arrow lights up. No gear icon.

[andrewwynn]

Abs fault that clears itself look for water in a wheel sensor or steering angle sensor.

You mentioned limp mode. That's when gear icon would come into play.

[Salty B.]

I swear I posted a reply earlier...

ABS fault cleared itself after a restart and this also exited limp mode, but SES light stayed on. The codes in the first post are what I got afterwards. But no gear icon ever. Just the triangle with the ! in it. Both times it happened I was at cruise speed, on a straight road. No braking or steering.

[andrewwynn]

What codes still come back after clearing?


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[Salty B.]

Originally Posted by andrewwynn

What codes still come back after clearing?

The fuel trim ones, repeatedly.

[andrewwynn]

Pull up real-time fuel trim info I think your scanner has that. Or pre cat O₂ voltages.

Work though the persistent errors and determine if they are just cascading into the other problems.

Odometer?

The e53 had a dumb fuel pump and FPR. The ECU assumes they are both working properly and getting you 50.0 psi to the fuel rail. When it doesn't, you will initially see the O₂ loop adding fuel until it can't anymore and you'll get the error you're getting.

If your fuel trims are maxed high that's the most likely reason. Get a fuel pressure gauge you can hook up to the rail and see if pressure is 50 and rock steady regardless of throttle position and stays pressurized overnight.

[Salty B.]

191,000-ish

Don't have the list of all the parts the seller replaced so status of fuel pump/FPR unknown.

I'll see if this scanner can do that this weekend (I'm away this week).

Thx again!

[andrewwynn]

A fuel pump will last about 5000 hours so 191/5=38.2 mph avg which is almost double the normal lifetime avg speed and/or there's almost zeeo chance pump is original. The FPR fauks from an o-ring inside that is more likely to fail from time and temp.

No fuel pressure sensor on e53 so you have to use an external gauge to test. I bought at harbor freight for about $27