Help, Advice, Owners' Discussion and DIY Tutorials on Volvo XC90s. The XC90 proved to be very popular, and very good for Volvo's sales numbers, since its introduction in model year 2003 (North America).
i have a 2006 xc90, 2.5 engine with about 70k miles on it. i purchased the car about 800 miles ago from a mercedes dealership, no warranty. car was strong, ran well. all previous maintenance done by volvo.
about two weeks ago, returning home from a mountainous area, car would not go up hill, would barely go up to 40mph. on a flat surface, it speed up to 70mph+ but it took significantly longer. in general, acceleration was weak.
two error messages popped up: "reduced engine performance" and "engine system service required".
i took it to my mechanic, the ran the error codes and found: 1) ecm-9400 2) ecm-940D
errors related to a faulty accelerator pedal sensor. the pedal was replaced with a genuine volvo part. the car started fine without errors twice and both error messages returned when i went to pick it up from them.
i took the car to another mechanic that specializes with volvos. he pulled these codes:
ecm-9400 accelerator pedal (ap) sensor, digital sensor - faulty signal ecm-940D accelerator pedal (ap) sensor, digital sensor - signal too low ccm-0090 lower switch faulty ID psm-002a operating button, memory 3 too long time psm-002b operating button too long time bcm-0031 wheel sensor, left rear faulty signal bcm-0041 wheel sensor, right rear faulty signal cem-8a21 low beam right signal too low cem-8b01 position lamps signal too low
he moved the new part around, poked around, erased the codes. car started fine twice again and error messages returned and the performance was again weak. he recommended going to the dealer in case the ecm is faulty and it is covered under warranty.
took it to the dealer, they pulled the same ecm codes. the checked the MAF and ETM and they were "fine". they recommended replacing ECM by process of elimination.
apparently the part is covered under manufacturer warranty up to 8yrs or 80k miles so i won't have to pay a dime.
my concern is that there is a possibility that the wiring inside the car from the ecm to the accelerator pedal sensor (and nearby sensors) are causing the error messages in the ecm. the wiring is not covered under warranty and can be tedious to repair and costly.
i heard back from the dealer today. they replaced the ecm but the error messages still come up. they said they're going to replace the pin connectors for the wiring. we may end up paying some of the repairs it seems.
has anyone experienced anything like this before? error messages after the ecm is completely replaced?
Sounds like the dealer is doing what is proper procedure given the new APM. The other codes are meaningless and show up from people holding switches too long and the bulb ones show up from burnt out bulbs. The two BCM codes are unusual but there is a connector in the back that may have been unplugged for some reason with key on that would set both at the same time.
so the error messages are gone, except for one relating to a bulb failure.
after they replaced the accelerator pedal sensor and the ecm (this under warranty), the error message was still on. shortly before the "reduced engine performance" warning came on, there was one bulb failure error message because the front right xenon headlight bulb burnt out. these are aftermarket headlights that came with the car when i purchased it. the volvo dealer repairman decided to unplug the headlight all together and reset the computer and guess what, the 'reduced engine performance' message was gone. somehow, the bulb failure was sending a faulty message to the ecm which in turn misread error codes with the pedal sensor which was replaced. in other words, i didn't need to replace the pedal sensor or the ecm for that matter. i have to install regular volvo headlights in and the errors shouldn't return at all.
i've driven the car for the past day and it's been fine. no engine power loss, speeds up just like before.
replaced the xenon headlights with regular halogen lights (not original volvo parts) after the codes were cleared and the ecm was replaced. no more error messages. car runs normal, accelerates fine with full power. this has to be the first instance of xenon lights causing faulty ecm error codes. (interestingly, when i removed the after market xenon lights i noticed that they had wired the power source into the fuse box which may have had something to do with the errors).