Wiring problems Volvo S70 2000 2.4 b5244s

[nurbek0056]

Hello, I have a 2000 Volvo S70 with a B5244S engine and Magneti Marelli ETM (electronic throttle).

The car is stuck in limp mode, very low power, and throws multiple DTCs in VIDA.
Most of them seem unrelated, but some are throttle and pedal related. Here's the full list:


---

Engine Control Module (ECM) errors:

ECM-2110: Front heated oxygen sensor – preheating malfunction

ECM-2210: Rear heated oxygen sensor – preheating malfunction

ECM-4000: EVAP purge valve – signal fault

ECM-6200: Idle air control valve (AACV) – signal fault

ECM-6400: Unknown (no description in VIDA – possibly internal ECM fault or communication glitch)

ECM-9150: Throttle position sensor 1 (TP1) – signal too low or missing

ECM-9160: Throttle position sensor 2 (TP2) – signal too low or missing

ECM-950F: Accelerator pedal position sensor – signal too weak or missing

ECM-9520: Accelerator pedal – signal mismatch or fault



---

ABS:

ABS-0010: Left front wheel sensor – no signal


CDM (Central Electronic Module):

CDM-000A: D+ signal from alternator too weak (low voltage warning)



---

So far, I’ve ruled out the following:

The ETM (throttle body) is tested and working.

The MAF sensor is good.

Pedal signals intermittently show up, but often drop to 0.

StarLine alarm system is installed under the dashboard.


I suspect a wiring issue between ECM and throttle/pedal sensors — possibly bad ground, interference from alarm system, or broken wires under the steering wheel.

Where should I look next?
Could StarLine or poor wiring under the dashboard be causing signal dropouts from APP/TP sensors?

[xanthefin]

Wrong engine ECM somehow in Vida selected (ME7 wrong >> Denso) most likely causing missing code.
Edit: Speedo/meter/Dashboard replaced in past? Vida gets then always wrong.

ECM-2110, Front heated oxygen sensor (HO2S), heating. Signal too high/low.
ECM-2210 Rear heated oxygen sensor (HO2S), heating. Signal too high/low.
ECM-4000 Canister purge (CP) valve. Signal too high/low.
ECM-6200 AACV. Faulty signal.
ECM-6400 Camshaft reset valve. Signal too high/low.
ECM-9150 Throttle position (TP) sensor 1. Faulty signal.
ECM-9160 Throttle position (TP) sensor 2. Faulty signal.
ECM-950F Accelerator pedal (AP) position sensor. Faulty signal.
ECM-9520 Accelerator pedal (AP) position sensor. Faulty signal or missing.

[nurbek0056]

Yes, that actually makes a lot of sense!
I did replace the ECM a while ago — I used the exact same part number and swapped the EEPROM from the original unit.
Also, I’m not 100% sure, but I think the instrument cluster might have been replaced by the previous owner.

[scot850]

If the cluster was replaced on a 2000 that will cause problems. The Vida system checks the data stored in the speedometer cluster for the Vin# and as a security check then compares to the ECM. If these Vin #'s do not match it will prevent ECM access. Also it will only display the km's from the swapped in speedometer cluster, not that of the original car. It was a security feature to prevent swapping a lower mileage speedometer unit it.

If your transmission is an automatic it must have come from a similar car as my 2000 V70 base (non-turbo) had a 5 speed auto transmission, earlier cars and turbos of that year had 4 speed in North America except the V70R, the only other car here with a 5 speed auto. The speedometer head does not like it if you put a 4 speed automatic car speedometer cluster into a 5 speed auto and the reverse is also true.

Maybe someone clever has figured out how to swap chips to make this possible, but Volvo says the motherboard in the cluster is NOT reprogrammable (by them). You have only one shot at programming and you cannot re-use motherboards.

Neil.

[xanthefin]

If the cluster was replaced on a 2000 that will cause problems. The Vida system checks the data stored in the speedometer cluster for the Vin# and as a security check then compares to the ECM. If these Vin #'s do not match it will prevent ECM access. Also it will only display the km's from the swapped in speedometer cluster, not that of the original car. It was a security feature to prevent swapping a lower mileage speedometer unit it.

If your transmission is an automatic it must have come from a similar car as my 2000 V70 base (non-turbo) had a 5 speed auto transmission, earlier cars and turbos of that year had 4 speed in North America except the V70R, the only other car here with a 5 speed auto. The speedometer head does not like it if you put a 4 speed automatic car speedometer cluster into a 5 speed auto and the reverse is also true.

Maybe someone clever has figured out how to swap chips to make this possible, but Volvo says the motherboard in the cluster is NOT reprogrammable (by them). You have only one shot at programming and you cannot re-use motherboards.

Neil.

I have stripped 2000 CDM in my foots area and.. it has external flash memory chip so no protections there i am afraid against reusage. Its like 1998 year model S80 which DIM had too external flash memory which i dumped as i wanted remove one annoying message to be never to be shown (its possible).

[nurbek0056]

If the cluster was replaced on a 2000 that will cause problems. The Vida system checks the data stored in the speedometer cluster for the Vin# and as a security check then compares to the ECM. If these Vin #'s do not match it will prevent ECM access. Also it will only display the km's from the swapped in speedometer cluster, not that of the original car. It was a security feature to prevent swapping a lower mileage speedometer unit it.

If your transmission is an automatic it must have come from a similar car as my 2000 V70 base (non-turbo) had a 5 speed auto transmission, earlier cars and turbos of that year had 4 speed in North America except the V70R, the only other car here with a 5 speed auto. The speedometer head does not like it if you put a 4 speed automatic car speedometer cluster into a 5 speed auto and the reverse is also true.

Maybe someone clever has figured out how to swap chips to make this possible, but Volvo says the motherboard in the cluster is NOT reprogrammable (by them). You have only one shot at programming and you cannot re-use motherboards.

Neil.

Thanks Neil — your explanation was very helpful and gave me more context.

To clarify my case:
The car had been running perfectly fine for a long time, including after the ECM was replaced (EEPROM cloned from the original).
Then one day on the highway, the throttle started cutting out intermittently — the pedal would stop responding for a few seconds, then come back.
After we got to our destination and restarted the engine, it went into limp mode, with unstable idle and no throttle response at all.

First I suspected the ETM, so I replaced it and cloned its firmware — no change.
Then I replaced the ECM with EEPROM, still the same symptoms.

[scot850]

For future reference, if you fit a used ETM if you fit one from the same model and engine type no need to re-program.

It is strange though that the car was running fine and then went into limp mode.

Are you able to clear the codes and see if they all come back?

Neil.

[Vova585]

Alarm system- it is possible that it might be a contributor to your problem especially if not wired correctly via soldering(lets be honest most places will use quick connect option). I would opt to toss it away and restore original wiring at some point(it is 25 year old classic, so doubt that Kia boys will be interested in it).

Accelerator pedal- thats seems to be more interesting issue. I can see it throwing the car into limp mode if signal is erratic and dropping to 0 as you mentioned. There some of them available on ebay for 20-30 so might be a cheap parts cannon try. Can possibly remove your pedal and bench test if resistance is changing proportionally without open circut.

My though- if the car was driving great before and accidentally went to limp mode- it is caused by 1 new problem. Agree with scot850 to try to erase all codes and do another test drive and see which codes will show first.

[nurbek0056]

Alarm system- it is possible that it might be a contributor to your problem especially if not wired correctly via soldering(lets be honest most places will use quick connect option). I would opt to toss it away and restore original wiring at some point(it is 25 year old classic, so doubt that Kia boys will be interested in it).

Accelerator pedal- thats seems to be more interesting issue. I can see it throwing the car into limp mode if signal is erratic and dropping to 0 as you mentioned. There some of them available on ebay for 20-30 so might be a cheap parts cannon try. Can possibly remove your pedal and bench test if resistance is changing proportionally without open circut.

My though- if the car was driving great before and accidentally went to limp mode- it is caused by 1 new problem. Agree with scot850 to try to erase all codes and do another test drive and see which codes will show first.

Thanks for the suggestions!
I cleared all the error codes, and after running another diagnostic session, no significant errors reappeared except the usual IMM 235 (which I understand doesn't really affect operation).
The engine is still running roughly — idle is stable at 900 RPM, no fluctuation, but it feels like it’s misfiring or not smooth.
I replaced the accelerator pedal with another one, but it made no difference.
Earlier, I also replaced the knock sensor, because VIDA had shown a knock sensor code before, but that didn’t improve the situation either.

Any thoughts on what else could cause these symptoms if ETM, pedal, and sensors are OK?

[Vova585]

I would hope abscate will weight in this one. He was recently suggesting ability to perform crank/cam correlation test through the vida. I think there is auto adaptation procedure for throttle body as well. Would be nice to see what %0 it starts on. Possibly can check fuel pressure for the sake of easy test(rough engine work, ? Misfire). But if I would have to bet- I would put my bet on vaccuum leak for engine unsteady work.