2004 volvo s60 2.4 stalling issue

cichy1012 · Post by **cichy1012** » 29 Sep 2023, 17:18

Car at idle(stop sign) or in park; rpms/engine surges up and down. Eventually will stall.
-cleaned throttle body-- control module was changed like 3 years ago
changed map sensor(one near the hood latch)
air filter
oil change
cleaned mass air flow sensor on the intake
changed some vacuum lines
changed fuel rail pressure sensor
changed out a few old coils and all spark plugs.

i have a p0037 h02s heater control circuit low bank 1 sensor 1 but heard thats common and vehicle is drivable. ive had that code for like 6 years.
now when i get pissed at it I rev the car like a hot rod and the surging stops for a bit then returns again. I attached a video

any help i appreciate it.

Post by **cn90** » 29 Sep 2023, 17:32

You should search forum for "PEM"...

Post by **jonesg** » 30 Sep 2023, 04:40

its beyond time to replace the O2 sensor.

Post by **chrism** » 30 Sep 2023, 06:30

Second vote for a new O2 sensor.

cichy1012 · Post by **cichy1012** » 30 Sep 2023, 08:27

Is that the last one in the system? After the catalytic converter? also would that cause stalling? I tried the PEM, and same thing.

Post by **chrism** » 01 Oct 2023, 07:44

Yes, I’m pretty sure that P0037 refers to the pre-heat circuit in the downstream (aft) O2 sensor. In fact, if you were to clear that fault code, you could very likely get it to reappear by just turning on the ignition and not even cranking up the engine, as the pre-heat circuit is activated as soon as the ignition is turned on.
Another clue that the O2 sensor might be your problem is that the car will run OK the first minute or two when first started cold. That’s because the O2 readings are ignored by the computer for the first couple minutes while the engine (and pre-heater) warm up.
Side note: If your car is non-turbo then the O2 sensors may be Denso brand. My 2003 2.4 non-turbo is a Denso car. It’s generally better to replace the sensor with one of the original brand.

cichy1012 · Post by **cichy1012** » 03 Oct 2023, 06:30

cichy1012 · Post by **cichy1012** » 03 Oct 2023, 15:37

cichy1012 wrote: ↑03 Oct 2023, 06:30
chrism wrote: ↑01 Oct 2023, 07:44 Yes, I’m pretty sure that P0037 refers to the pre-heat circuit in the downstream (aft) O2 sensor. In fact, if you were to clear that fault code, you could very likely get it to reappear by just turning on the ignition and not even cranking up the engine, as the pre-heat circuit is activated as soon as the ignition is turned on.
Another clue that the O2 sensor might be your problem is that the car will run OK the first minute or two when first started cold. That’s because the O2 readings are ignored by the computer for the first couple minutes while the engine (and pre-heater) warm up.
Side note: If your car is non-turbo then the O2 sensors may be Denso brand. My 2003 2.4 non-turbo is a Denso car. It’s generally better to replace the sensor with one of the original brand.
so i replaced the o2 sensor. I did not replace it with a denso though. and also the check engine light i still on. It still went into the surging but whats strange is that it wasnt as frequent and did not stall; but yet still rpm surging, then ran for quite awhile until i came home and put it in park it would surge. Im not sure if i have caused issues all the way down the line or not. I swapped out 3 different PEMS (fuel modules) so i know it cant be that. should i clear the check engine light code and see if it pops up again?

Also I thought cleaning my mass airflow sensor would help. I noticed when the car started surging, I unplug my mass airflow sensor in the car got better, it stop surging as soon as I plugged it back in the car stalled.

Somone suggested that my throttle body my be going even though i cleaned it out; it may be failing from the electronic side. guess ill try that next?

Post by **chrism** » 04 Oct 2023, 15:28

I would clear the fault code and see if the same one, or any new ones, reappear.
I’m curious - what brand of sensor came out of the car? What brand of sensor is the replacement? Was it a “plug and play” type that you simply plug in or did it come with pigtail leads that required splicing? Did it have the same number/color of wires as the original?

Also, might there be any leaks in the exhaust system that could be throwing the O2 reading off? How about vacuum leaks? Consider that the brake booster can be the source of a vacuum leak. Temporarily capping its hose or pinching the hose shut might be a good test.

Was there any work done to the car recently like a PCV service, or manifold removal? What kind of spark plugs are you running?

cichy1012 · Post by **cichy1012** » 05 Oct 2023, 06:32

chrism wrote: ↑04 Oct 2023, 15:28 I would clear the fault code and see if the same one, or any new ones, reappear.
I’m curious - what brand of sensor came out of the car? What brand of sensor is the replacement? Was it a “plug and play” type that you simply plug in or did it come with pigtail leads that required splicing? Did it have the same number/color of wires as the original?

Also, might there be any leaks in the exhaust system that could be throwing the O2 reading off? How about vacuum leaks? Consider that the brake booster can be the source of a vacuum leak. Temporarily capping its hose or pinching the hose shut might be a good test.

Was there any work done to the car recently like a PCV service, or manifold removal? What kind of spark plugs are you running?

cleared codes and nothing comes back
original sensor had volvo on it.
new one is plug and play
spark plugs are ngk laser platinums i believe with 3 prongs- replaced those last year
no pcv service or manifold removal done.
when you say brak booster are you meaning the hoses and sensor right there in front by the head light and air filter box?