2001 S40 1.9T starts but does not idle

[alschnertz]

The throttle body is the device that has the accelerator cable connected to it and has a large disc inside it that pivots (depending on how far open the throttle is) to let more air into the intake manifold as you step on the gas.
You will have to remove the plastic cover on the left side of the engine to access it.
I kind of doubt it is your issue, but at 147K, it is due for a cleaning.

Under the throttle body is a somewhat large vacuum hose. I know this will cause "idle" stalling if it's disconnected or broken because that is something I experienced when I forgot to re-attach it after a PCV service.

The attached photo shows the throttle body. The plastic cover has not been removed in the photo. The throttle body is the piece hiding behind the white tee.

[S40V70DAD]

Update:
- used STARTER FLUID to go hunting for vacuum leaks - this did not yield any obvious leaks.
- saw a post stating that the FPR (fuel pressure regulator) was the culprit on one persons car. It's a $140 part, will first try measuring the fuel pressure to determine if there is any issues. Can anyone tell me what the normal range is while running ?

[alschnertz]

40-44 psi.

[S40V70DAD]

Alschnertz, thanks for your prompt replies !

Update: Can't believe it myself, but it was a FUSE! I can duplicate the problem by swapping the "bad" 10A fuse back into the Fuel Pump slot.

FINAL SOLUTION:
Read that a Fuel Pressure Regulator solved one guys similar if not exact issue according to his description. So not wanting to spend $140 to find out, I wanted to use a Fuel Pressure Gauge to simply measure the pressure - but in one day could not find one to borrow. So I did a lazy man and depressed the Schroeder valve on the test port and fuel spewed out. Not sure if the pressure was adequate but there was pressure, AND, also because the car ran fine operating the foot throttle also seems to indicate to me that the fuel is being delivered just fine. So then I thought to at least check the FUSE - it looked weird somehow in the loop arch, couldn't tell if it was blown, ohm'd out using a DVM and it rang the continuity beeper. Also the leads were discolored, but all my fuses are discolored. side note: Previously I had a Cruise Control issue not working that seemed to be fixed by cleaning the tarnished leads on the FUSE. So I cleaned the leads on the 10A Fuel Pump fuse and re-inserted it. - No change. I did the same to a few other fuses (10A Engine Sensors ? , 15A VACUUM PUMP), and each time went to start the car. - No change. The other fuses looked perfect, to it got me thinking WHY the weird looking fuse in the Fuel Pump slot? So, Then I swapped out the 10A Fuel Pump Fuse with another 10A fuse, and the CAR STARTED AND IDLED with no foot operation of the throttle pedal. I was able to swap the "bad" fuse back and the car would not start, swapped it again with the other 10A fuse and the car would start.

[S40V70DAD]

Can't believe it myself, but it was a FUSE! I can duplicate the problem by swapping the "bad" 10A fuse back into the Fuel Pump slot.

To be clear here was the cars' issues:
Symptom: Starts but does not idle; runs fine with foot operating the throttle, but stalls immediately if you remove foot.
Originally it ran for a week after purchasing car, then the problem appeared intermittently, 2-3 times in one week – wouldn’t idle upon start-up but then ran fine after it was run/warm for several minutes. THEN, a few days later, it became a HARD FAILURE, constant all the time will die without operating the throttle. FYI; OTHER odd note, the FAN coming on even when cold.

ACTIONs TAKEN:
1) Removed and cleaned ICV (idle control valve)
2) Bought and installed brand new ICV
3) Ordered an OBDii reader to get codes (but from other posts here I don’t see this leading to resolve)
4) bought STARTER FLUID to go hunting for vacuum leaks. Nothing obvious found (person in car kept a steady idle as I sprayed starter fluid over vacuum hoses and all around).

FINAL SOLUTION:
Read that a Fuel Pressure Regulator solved on guys similar if not exact issue according to his description. So not wanting to spend $140 to find out, I wanted to use a Fuel Pressure Gauge to simply measure the pressure - but in one day could not find one to borrow. So I did a lazy man and depressed the Schroeder valve on the test port and fuel spewed out. Not sure if the pressure was adequate but also because the car ran fine operating the foot throttle also seems to indicate to me that the fuel is being delivered just fine. So then I thought to at least check the FUSE - it looked weird somehow in the loop arch, couldn't tell if it was blown, ohm'd out using a DVM and it rang the continuity beeper. Also the leads were discolored, but all my fuses are discolored. side note: Previously I had a Cruise Control issue not working that seemed to be fixed by cleaning the tarnished leads on the FUSE. So I cleaned the leads on the 10A Fuel Pump fuse and re-inserted it. - No change. I did the same to a few other fuses (10A Engine Sensors ? , 15A VACUUM PUMP), and each time went to start the car. - No change. Then I swapped out the 10A Fuel Pump Fuse with another 10A fuse, and the CAR STARTED AND IDLED with no foot operation of the throttle pedal. I was able to swap the "bad" fuse back and the car would not start, swapped it again with the other 10A fuse and the car would start.

[alschnertz]

Wow, didn't see that coming.
Great news.

[S40V70DAD]

CORRECTION: It was a fuse, but it was the 10A ENGINE SENSORS fuse, NOT the 15A Fuel Pump fuse.
The fault code signature I got when re-installing the 'Bad" fuse were: P2401 P0445 P0031 P0037 P0245

[pmondrian]

Congrats on fixing the problem.