Electrical issues questions - P1 C30

[Vova585]

It appears that battery is doing fine. You can easily charge it and drive the car to the advance to have free test which will show internal resistance/state of charge/ state of health/ remaining cca. However if the battery is healthy enough to start the car it is not your issue almost 100%. In terms of charging system-you sure can start the car and turn on all heavy users(high beam, blower, rear heater) and see what alternator provides to the battery. I would pay attention if upon turning key to position 2 battery indicator lamp illuminates. If it illuminates and almost immediately gone after starting that's great. So logically if the starting system would malfunction you would get battery light on the dash and the car would drain the battery, but it would work. Your car is shutting off upon warming up. I would concentrate on trying to reproduce the condition and have my probes ready to see what is missing(injector pulse, fuel pressure(would guess it would hesitate like a lawnmover running out of gas instead of falling on its face), spark). And knowing what gives you will be able to narrow your search. I would try to encourage you to think line a paid by work mechanic and "design the plan,work the plan". You may clean all powers and grounds in this car, but if the issue is inside the ecu, broken wire you would just waste your time.

[scot850]

I agree with your suggestions. Problem I have with this is there have been 2 mechanics in there before me and some of the wiring and repairs to it is questionable. I want to do the basics and check they have not damaged things like connector pins, there is no corrosion in connectors and ideally where wires are in vulnerable locations they have not been stressed or nicked.

I probably don't have the skills to look into the ECM, but I'm hoping to narrow it down to as few possible potential sources first. It still only have the one check light error and I can easily believe whoever did the hack job and shortened the wires so much they cut close the exhaust manifold and another couple of wiring repairs will also need to be investigated for quality. I may have to replace the wire to the turbo controller as they do not look good. I may have to go to a junkyard and see if I can find that part of the loom as I understand the engine bay loom is NLA from Volvo.

I agree the battery is probably ok, but I will test the charging system. The battery does pass my testers tests but does read low. I also have equipment to test the charging system so will do that to eliminate that. I also plan to pull the CEM as apparently the sunroof drain leaked on the RHS. Again to eliminate it from being an issue and having no corrosion or burn areas if it got wet.

I have time and if I don't find the smoking gun, I will have saved the owner a lot of money potentially if the ECM turns out to be the issue he will need that for a replacement from the likes of Xemodex.

Appreciate the help guys!

Neil.

[Vova585]

On my quick ebay search I was able to find entire engine bay harness for c30 located in Canada for about $250US or best offer. If the money are not very tight and existing wiring is in dire shape...yes it is a lot of work to replace harness, but not too terribly bad. This way you can hope that wires are not shorted together and each ground contact is properly addressed upon installation ( i absolutely love NO-OX-ID paste at every ground terminal especially with xc60 and it's not great design of water run off from windshield. If the plastic channel slightly off track all the salty winter brine washes onto the ground connector under the air filter housing).

[scot850]

I will take a look for that harness as parts of the existing are not great. Thank for the paste suggestion. I just watched a video on someone cleaning the contacts on the CEM following a sunroof drain leak. I still have to check that as they have had that issue. I'm not sure what in there could cause a limp mode. The only code so far is for the turbo boost signal. The wiring for that is bad. My mechanic buddy things he might have that part of the harness. He says the easiest way to access it is to drop the subframe. I remember a lot of swearing on mu friends V50 AWD replacing this inaccessible part!

Neil.

[Vova585]

I will take a look for that harness as parts of the existing are not great. Thank for the paste suggestion. I jut watched a video on someone cleaning the contacts on the CEM following a sunroof drain leak. I still have to check that as they have had that issue. I'm not sure what in there could cause a limp mode. The only code so far is for the turbo boost signal. The wiring for that is bad. My mechanic buddy things he might have that part of the harness. He says the easiest way to access it is to drop the subframe. I remember a lot of swearing on mu friends V50 AWD replacing this inaccessible part!

Neil.

I salute your determination,sir. Anything that would require subframe work would go to a professional shop with lift and dedicated holders for transmission and engine. My safety trumps my desire to save someone money.

[scot850]

These engines are supported by engine mounts so removing the subframe is no big deal like most other FWD/AWD Volvos.

I also have hoist and access to an ex-Volvo mechanic who owns 2 of these. I'm hoping he is able to find the part of the wiring harness I would like to replace which he thinks he has.

No guarantees, but we will see how this goes, if nothing else a good learning opportunity!

Neil.

[chrism]

Maybe I missed it somewhere, but what fault codes are you getting?

[dikidera]

The S40/v50/c30 etc of p1 all have issues with the CEM, this results in many electrical gremlins.

It has been a known issue in my country and there doesnt go by a day where someone doesn't complain about it.

[scot850]

To answer your questions:

chrism: The owner has had several codes, but currently I just had the one by scanning with my Autel 802. My Vida/Dice will not talk to the car. It has a hissy fit and will not connect, although the Autel does. The code is noted below, and sorry, I thought I had listed this somewhere previously.

I've linked the original thread in the P1 forum where there was no real traction as I felt this is a general error initially:

viewtopic.php?t=106499

Therefore I do not have a Volvo 'code' with a 'P' suffix, only a general number ECM-640C. I cannot find a cross reference to this code and Google (AI) just gives you nonsense as an EGR code (car does not have one). It is a code for turbo controller signal low (or high depending where you read). The wiring for that cable is really butchered and I will likely replace it. Downside is the harness was only fitted to this spec of car for 2007 as the engine changed from a T3 to T7 variant in 2008. The engine harness is NLA new (part # 30764853). My Volvo parts guy (great help) has identified tis harness is used in C70/S40/V50 including AWD up to possibly 2007 as well. Again engine change in the turbo for 2008. The parts guy cannot get from Volvo what the change in harnesses are. I believe it may be as simple as the oil level sensor but so far not sure what year that happened in. A friend of mine has a 06 V50 T5 AWD manual running the T7 motor just fine. There were a couple of minor changes possibly done but I don't know which harness was used.

I think that there are possibly 2 or more issues going on and I'm slowly working my way through the harness and connections to try to eliminate any possible issues.

However, there are other possible factors going on in the electrical world on this car that need further investigation:

1) The infamous sunroof drain pipe issues that plague P1 cars. My buddy (the ex-Volvo mechanic) says it is a common issue caused by bad design. The pipes at the front drains have a join about the level of the dash (making access just perfect ). As the pipes age they shrink and separate causing water leaks into the cabin and into the CEM behind the glove box. I still have to pull the CEM but I'm waiting for some De-ox gel to add to the pin in the main ECM connectors and any other connectors before I go pulling more apart (should be here today).

So as Dikidera points out it is a pain. My mechanic buddy has 2 C30's and one is in bits to fix this issue and dry out the interior. Even the seat runners are seized (he has spare seats for me to transfer the seats onto the spare seat bases).

2) I think somewhere along the line the battery may have been overheated as the +ve post leans to one side and the area around it is bubbled. Talking to an Interstate battery advisor, they concur this would be the likely cause of the damage. The cells have a much lower fluid level in the 2 cells closest to that end and a bunch of corrosion residue around the base of the wiring connector to the +ve contact.

I took pictures but it does not really show the issue as clearly as you see with your eyes. The battery is huge (H7) but the voltage after charging is only 12.35V after resting. I know the P80's don't like low voltages around 12V so perhaps this battery is contributing to the issue due to low voltage but with such a huge cranking amp (970 CA/790 CCA) I think the car may be working ok due to the huge current capacity. With the post being bent it is possible that when warm the battery post internally may be disconnecting? Hard to prove.

I don't want to suggest changing the battery until all other avenues have been checked.

So lots of challenges and not currently (sorry pun not intended! ) not a lot of time, it will just be a laborious process of checking everything including the alternator as they run hot in these engines due to proximity to the turbo and poor air flow to the alternator.

So lots of work, but no obvious smoking gun, but possibly multiple contributing issues? Or just one with a bunch of those red herrings!

Thanks,

Neil.

[scot850]

Spent an hour yesterday trying to get enthused to strip the grounds and clean all the connectors in the engine compartment after getting the No-Ox-it paste recommenced by Vova585.

Discovered the engine harness (part # 30764853) is NLA (it is also in the region of $1500 CDN for an engine harness!). One year option in 2007, first year of the C30 in Canada. Supposedly a S40/V50 harness from 2004-07 is the same for the T5 variant with auto trans.

The engine harness looks fairly small in the Volvo parts drawings. Reality it covers the whole engine bay so will be a bear to remove if I can find one. I cannot get from Volvo what the differences are for the 08- harness precluding using it.

If anyone can find wiring diagrams for 2007 and 2008 Turbo automatic P1's or send me links to them it would be appreciated so I can try and figure out if they are hopefully compatible with possible minor redundancies or pinning changes.

Neil.