2000 V70R - Intermittent Major Electrical Fault

tightmopedman9 · Post by **tightmopedman9** » 10 Mar 2015, 11:46

Well, turns out the problem is not resolved.

I received the following codes from VIDA when read:
ABS-0070 Pump motor faulty signal
ABS-0091 Control module communication
ECM-530D Malfunction indicator lam (MIL) TCM - Faulty signal
ECM902A Throttle unit communication - signal too low
ECM-959F Accelerator pedal (AP) position sensor - Faulty signal

I replaced the electrical portion of the tumbler (ignition switch) and the problem re-occurred. My thoughts are that there is a wiring harness fault causing CAN-BUS communication errors.

I'm not sure exactly where to start looking.

tightmopedman9 · Post by **tightmopedman9** » 10 Mar 2015, 11:49

I'm going to try and replace the brake light switch:
http://www.volvoforums.org.uk/showthread.php?t=105578

Post by **misha** » 10 Mar 2015, 12:10

I don't have experience with "etm"cars but i think that code for throttle unit communication is because of bad etm module.

tightmopedman9 · Post by **tightmopedman9** » 10 Mar 2015, 15:45

The ETM has been replaced 3 times, used OEM and 2 Xemodex units.

The brake position sensor and brake switch didn't fix the problem.

I'm going to check the main wiring loom.

Post by **misha** » 10 Mar 2015, 16:34

tightmopedman9 wrote:...They noticed that when the problem occurred the ECM would drop off the CAN-BUS network, even though the car was still running. They cleaned the ECM contacts at the same time as replacing the ECM relay and the problem was fixed.

I'm reading the whole thread over and over again and it definitelly have something to do with this can-bus thing.It's either intermittent fault with a chipped key,immobiliser or bad ecu.
When i say chipped key,it might be the key itself,antenna ring or immobiliser NOT sending recognition code to ecu via CAN line....intermittently.That would explain dropping off from can-bus network.

Other than that...ecu or it's CAN line might be bad.CAN line should be controlled by immobiliser.Or ecu don't recognise codes sent from immobiliser at some point.That said...data might me corrupted,but not corrupted enough to stop the engine from running.

If it is wiring problem it would be constant.This points to electrical problem,like relay or something,because it is temperature related.When i say temperature related i meant to say when something runs for a while and develops some working temperature and when that temperature occurs...problem appears.

It could be anything from cold solder on ecu & immobiliser print board to cold solder at ecu relay.

Post by **abscate** » 10 Mar 2015, 19:57

There was a long thread last year about someone with a electrical bus issue that was heat soak related. Sorry I can't be more specific but will search.

tightmopedman9 · Post by **tightmopedman9** » 12 Mar 2015, 01:45

After talking with a Volvo tech, it does seem to be heat soak related. The problem occurs with much greater frequency after the car has been driven for a long period or frequently restarted.

Abscate, is this the thread you were talking about?
https://www.matthewsvolvosite.com/forums ... 11&t=24832

It is about S80s and the common culprit of the CEM. Correct me if I'm wrong, but the P80 ME7s don't have a CEM, right?

One poster recommended re-soldering all of the CAN bus wires. I think I might give this a try tomorrow.

tightmopedman9 · Post by **tightmopedman9** » 12 Mar 2015, 02:07

I've been going over my VIDA readout and thing I may have found something worth investigating.

There are codes associated with CAN bus signal being too low for every module. It looks like the only module that has triggered these codes is the CDM with CDM-DF14 and CDM-DF15. I am also getting CDM-E000, control module communication, and ECM-530D, which apparently is triggered when a fault is is found with the check engine light.

I'll start with re-soldering the CDM CAN lines.

Post by **abscate** » 12 Mar 2015, 05:59

tightmopedman9 wrote:After talking with a Volvo tech, it does seem to be heat soak related. The problem occurs with much greater frequency after the car has been driven for a long period or frequently restarted.

Abscate, is this the thread you were talking about?
https://www.matthewsvolvosite.com/forums ... 11&t=24832

It is about S80s and the common culprit of the CEM. Correct me if I'm wrong, but the P80 ME7s don't have a CEM, right?

One poster recommended re-soldering all of the CAN bus wires. I think I might give this a try tomorrow.

Pretty sure ME7 has no CEM, sorry for the misdirect.

2000 V70R - Intermittent Major Electrical Fault

Re: 2000 V70R - Intermittent Major Electrical Fault