CEL and reduced engine performance

curt698 · Post by **curt698** » 04 Dec 2018, 07:26

Okay vital stats: 2004 s60 T5 AWD with 208,000 miles. Length of ownership, maybe a month. Came with CPS, TPS, and MAF codes and a check engine light.

So far I have replaced the CPS and TPS and replaced plugs (last step was probably a waste the plugs I took out looked good). After replacing the CPS I noticed no change. After changing the TPS I noticed a BIG change, much better throttle response and much smother shifting. I am however still getting at least 2 reduced performance messages on almost all drives. I am NOT a mechanic and know zip about Volvos, any idea on what else could cause this error? It seems to trigger when coming off low/no throttle and rolling onto it. One strange note, the error doesn't seem limit performance much if any. Even when the CEL was on the car seemed to run well. After installing the plugs I removed the neg terminal on the battery and clear all codes. With in 40 miles it through another CEL, haven't had the codes read yet. Hoping to find a scanner to borrow that might provide more info than the one at the auto parts store. Any help is appreciated I'm very frustrated at this point.

Post by **abscate** » 04 Dec 2018, 18:20

You won't progress until you get the codes read, and preferably the Volvo ECM-zxxxx ones

After 40 miles I would guess that's an EVAP code but guessing is really pointless

curt698 · Post by **curt698** » 04 Dec 2018, 19:51

Thanks, I have a scanner coming from Amazon Thursday. I will report back my findings then.

Post by **shiloh51933** » 07 Dec 2018, 07:45

curt698 wrote: ↑04 Dec 2018, 19:51 Thanks, I have a scanner coming from Amazon Thursday. I will report back my findings then.

The "reduced engine performance " message usually is in relation to brake booster system ...maybe brake pedal sensor(also power booster sensor) or booster vacuum switch or hoses to and from vacuum switch. Factory codes.

curt698 · Post by **curt698** » 07 Dec 2018, 07:54

shiloh51933 wrote: ↑07 Dec 2018, 07:45 The "reduced engine performance " message usually is in relation to brake booster system ...maybe brake pedal sensor(also power booster sensor) or booster vacuum switch or hoses to and from vacuum switch. Factory codes.

That is interesting info. I got my Bluetooth scanner yesterday and installed the Torque app. I'm still learning how to read and configure the app but yesterday it showed a LOT of Vacuum and very little boost. I guess that is expected for a 14 year old car with almost 210k miles. The good news is that I'm down to just one fault now. I'm still get a Crank sensor low volt code. Hope to pop the hood and find the cause of that tonight.

Post by **shiloh51933** » 07 Dec 2018, 08:37

curt698 wrote: ↑07 Dec 2018, 07:54
shiloh51933 wrote: ↑07 Dec 2018, 07:45 The "reduced engine performance " message usually is in relation to brake booster system ...maybe brake pedal sensor(also power booster sensor) or booster vacuum switch or hoses to and from vacuum switch. Factory codes.
That is interesting info. I got my Bluetooth scanner yesterday and installed the Torque app. I'm still learning how to read and configure the app but yesterday it showed a LOT of Vacuum and very little boost. I guess that is expected for a 14 year old car with almost 210k miles. The good news is that I'm down to just one fault now. I'm still get a Crank sensor low volt code. Hope to pop the hood and find the cause of that tonight.

The brake system codes aren't regular DTC issues, you have to have ability to team OEM trouble codes and/or ability to read ABS system codes.