Hello all,
I am running into some issues that are making life difficult for my daily driver and wanted to get some feedback and advice on the problems.
I have a 1999 C4 Coupe with ~122k miles on it. I have owned and maintained the car for the last 60k give or take. I have a K&N intake and gundo hacked
Problems are as follows:
Idle surge from 700-1200 RPM's (each surge is accompanied by an audible air sipping noise that can be heard outside the car near the engine).
ABS/PSM lights come on randomly (always together). I've noticed this happens more often when using partial throttle but decelerating. Turning the car off and back on usually clears these lights but they come on nearly every day now.
Car will occasionally go into limp mode. It doesn't completely die it just stops responding to throttle input. Sometimes the car also dies. This is most common at low speeds and restarting the car fixes the problem.
It is throwing a CEL. I will detail the codes below that I obtained with the Durametric scanner.
P0140 - Oxygen Sensor after TWC, bank 1
P1118 - Factory Fault Code 4 - Oxygen sensor heating after TWC, bank 2
P0102 - Factory Fault Code 115 - Mass Air Flow Sensor
P1119 - Factory Fault Code 5 - Heating of oxygen sensor ahead of TWC, bank 2
P0159 - Factory Fault Code 23 - Ageing of oxygen sensor after TWC, bank 2
P1266 - Factory Fault Code 409 - Fuel Shutoff Function Monitor
P1505 - Factory Fault Code 404 - Throttle Jacking Unit, Control Range
P0139 - Factory Fault Code 17 - Ageing of oxygen sensor after TWC, bank 1
P1501 - Factory Fault Code 403 - Throttle Jacking Unit, Output Stage (signal implausible)
P0160 - Factory Fault Code 20 - Oxygen sensor after TWC, bank 2
Alarm Fault Codes - These relate to separate issues I am going to address later (unable to program key, alarm goes off randomly)
33 - No passenger compartment monitoring
60 - Central locking limit position locked not reached
48 - Airbag signal acknowledged
I have a few theories based on my research thus far but thought this would be a good place to discuss them and possibly get insight from people with more experience and wisdom on the topic than myself. I think a large portion of the codes stem from a somewhat recent change to catalytic converters. The placement of the O2 sensors were vastly different on the replacement units that they were on my original units. I have attached pictures of the new cats and a stock photo that shows the old ones. I installed all new O2 sensors at the same time I installed the new converters. This was done at 106k.
At 112k I replaced the evap purge valve to fix a non starting issue. At the same time I also replaced the MAF sensor with the most current revision in hope of clearing up the ABS/PSM lights coming on. Clearly it didn't work haha.
The throttle jacking code makes me think it could be an issue with the throttle body which isn't terribly expensive or difficult to replace, so this is the one I am rooting for!
I've read some posts relating the P1266 to ECU failure which requires the ECU to be rebuilt or replaced. While it isn't too hard to get to, it's not cheap either.
Any info or suggestions are appreciated! Thanks everyone!
Brock