Multiple Fault Codes
 

Hi all, looking to see if anyone has any ideas of where I can go with figuring out what has gone wrong with my car. Apologies, its a bit long winded.

A week and a half ago my V70 was working absolutely fine. I parked up for the evening and then somebody decided that my car was carrying too much weight and relieved me of the obviously heavy catalytic converter and of course both oxygen sensors went in the 3 for 1 deal :mad:

While subsequently moving my car from the front to the side of house to work on it it ran like a bag of nails (stalled about 3 times) and now that I have a new cat and sensors it still runs like a bag of nails after taking forever to eventually catch and start. It stalled a lot at first. The idle doesn’t sound steady but the rev needle is fairly stable around the 850 mark. When I clear the codes the idle jumps all over the place but eventually goes back to rough. When moving the car I need a bootful of loud pedal to prevent it from stalling like I did when there was no cat at all.

I’ve interrogated the car with VIDA and got a ridiculous number of ECM prefix faults:

1200 - Air intake temperature low signal
1300 - MAF flow too high
1600 - Boost pressure sensor low signal
170F - Boost pressure sensor faulty signal
2000 - Coolant temp sensor low signal
280A - Front o2 sensor faulty
8010 - Battery voltage too high
904C - Reconfiguration emission system
904D - ETS light on
9530 - Acceleration pedal (AP) position sensor high signal
9540 - AP sensor power high signal
958F/959F - AP position sensor faulty signal
982A - ETM?

Not all codes appeared at the same time. One or two were there to start with and no longer appear and there are some new ones that popped up along the way.

Over the last few years its had a new Bosch MAF, alternator diode pack, battery is 2 years old, ETM was replaced with new contactless one from Volvo and also coded in by Volvo. Volvo don’t stock new catalysts or front o2 sensors anymore so I’ve had to go for an aftermarket cat but at least managed to get Bosch o2 sensors. Engine temp gauge works but the fan runs at max from cold.

If its likely to be an ECM issue do they just fail or are they susceptible to missing sensors? Is it possible the ripped out wiring from the rear o2 sensor has shorted something (heater circuit), there were 3 exposed cable cores dangling, the 4th broke inside the conduit. Or is it one of those fabled dead battery scenarios? It’s on charge anyway so will try again in the morning with another battery too if needs be. Is it all part of the bedding in of a new cat?

If anyone has any ideas or thinks I’ve missed something simple then please chip in.

Thanks in advance, Drew.

Guess everyone is out of ideas like I am. I checked spark plug gaps, all good there. Charging the battery did nothing, had just over 12.7V, 13.86 when running, 13.8 at B+ and the cabling in that fuse box is in really good condition too. Put a known good battery in and still the same.

I'm starting to think I've got a fried ECM as 904C code should always appear with 9150 or 9160 as it indicates a throttle position sensor fault in the ETM. I don't have those so am assuming the ECM has gone rogue. That coupled with all the other codes for stuff I knew was working fine up until last week.

Does anybody know if it's possible to fit a donor ECM or does it have to include other parts to get round the immobiliser issue? Can ECM repairs be done or is this likely the end of the line for the car?

Cheers.

Hi Drew

You say "ETM was replaced with new contactless one from Volvo"
I didn't know that Volvo made a contactless one. Is this for your 1999 V70 T5?
When was the ETM replaced and coded? Did the car run fine after that?

How did you fix the "ripped out wiring from the rear o2 sensor ... 3 exposed cable cores dangling"? Did you replace a short loom, or just fit a new plug etc?

Is there any doubt that you have fitted the correct O2 sensors for your car (and ECM)?

Do you have Vida yourself?

HTH
Steve

Knackered ECU
 

Thanks for responding Steve.

I had an ETS light (no CEL though) a few years ago and with Vida found an undeleteable code for ETM position sensor. I bought a Sacer contactless one and fitted it. The throttle still worked but the fault code still wouldn't go so figured the fault was terminal. I bought a new throttle body from Volvo and fitted it. The car started straight away without recoding from Volvo and the faults were gone. I noticed that the plastic end caps for the position sensors were cast different. One was like the original and the other was identical to the Sacer one but with Volvo embossed on it instead. I'd already paid for the software from Volvo by this point so just paid the labour and they updated the car to the latest (2006?) software version available.

The ripped out wiring was the from the sensor end of the lead. They unplugged the front sensor but the rear is connected differently so it was left alone. It was this 4 core lead that got wrecked. The black signal wire snapped halfway up the conduit that clips to the cat and the 2 white sensor heater wires and the grey earth had about an inch each of stranded core exposed from where it got pulled out of the sensor head. I think this is what has caused the short as I took the ECU out and found a burnt out track on the PCB. The main loom was fine and a new sensor was fitted for which I had no further fault codes.

I have checked and double checked Volvo part numbers against Bosch part numbers etc and confident that I ordered the correct parts. As mentioned above there is a definite fault with the ECU and it's away for repair at the moment. The car ran like a bag of nails and stalled several times with fault lights while moving the car 20 yards from front driveway down the side of my house. But a few hours earlier before the cat was cut out the car was absolutely fine. So the issue was present before the new parts were fitted.

And yes I have Vida/Dice. I got it to help find the ETM/ETS fault 2 or 3 years ago.

Basically it's a duff ECU. The company that has it also do cloning so hopefully I'll get a solution either way.

Drew

Hi Drew, I haven't got anything helpful to add other than that you seem to be on the right track with the ECU repair etc., but just wanted to express sympathy for the situation you've been put in by criminal scum. If it happened to me I'd be absolutely furious and totally gutted, so well done to you for gritting the teeth and getting on with sorting it.

Hope it all goes well, let us know how it turns out in the end. Cheers! :teeth_smile:

As an aside, make sure that all of your vacuum pipes and the ones that go to the inlet manifold are on correctly and in good condition. If you have the vacuum tree check the pipes there.

Fixed!
 

It turned out that my ECU had indeed suffered internal damage due to external influence. It has been repaired and refitted and the car now works as it should again. The cars been dead for so long I’d forgotten how good the exhaust growl was :teeth_smile:.

Thanks to everyone who got in touch.