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:
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.
should i be worried? i get the car back tomorrow.