V50 1.6D Short circuit and dead car - CEM the culprit?

[Frenchlangers]

You're both absolutely right - I have been blindly following YouTube videos on how to check for a short circuit which are not helpful at all. I will follow your advice on proper methods tomorrow.

I charged up the battery last night and the car started for about a second this morning before cutting out. It now turns over but doesn't start at all. What's the best approach to isolating the problem?

[Bungo]

Sounds like fuel issue then. When was the last time filter was changed ? Check clear pipe for air bubbles, crack injectors to check for fuel. You could try some easy start into air intake. Getting it hooked up to a Vida would be useful.

[Frenchlangers]

Thanks Bungo. The diesel filter was changed last month so am pretty sure that's ok. I took out all the injectors this morning and inspected them - they seem fine and there is fuel in the supply pipes.

I don't have Vida but I do have an ICarsoft reader which I ran through this morning. On the data streams (which I admit not fully understanding) there are a few bits of information which may explain why it is not starting:

Under the CEM analysis: Immobiliser, Engine control module = not ok (although fluctuates between ok as well from time to time).

ECM module is not accessible at all.

I am back to assuming the CEM/ECM are faulty or are not happy with each other. Is there any way a Volvo garage can test the CEM out of the car? I live a long way from the nearest garage (1 hour plus) and as the car is immobile it would be much easier and cheaper for me to remove the CEM and just take it on its own to a garage. Would that work do you think?

Many thanks again for all the support. Much appreciated.

[cheshired5]

Use the live data on your icarsoft to find the fuel rail pressure during cranking.
Also find the coolant temperature.

[Frenchlangers]

I hope I'm taking the right readings here

fuel pressure sensor = constant at 4300hpa

For the coolant, I can only find the coolant temperature sensor which gives a constant reading in volts at 19.76.

The fuel temperature sensor is also constant at 22 degrees.

Does this help?

[cheshired5]

Originally Posted by Frenchlangers

I hope I'm taking the right readings here

fuel pressure sensor = constant at 4300hpa

For the coolant, I can only find the coolant temperature sensor which gives a constant reading in volts at 19.76.

The fuel temperature sensor is also constant at 22 degrees.

Does this help?

I'm afraid it doesn't help no.

You need to tell us exactly what you're doing, whether the ignition is on or off, whether the engine is running, idling, revving......
We aren't there with you so we need you to describe everything.

Coolant temp as a voltage is also of no use.
The voltage of 19 will be wrong anyway..

[Frenchlangers]

Sorry about that. I can't seem to find the data stream on the coolant temperature. I have attached a screen shot of some of the streams.

Key out / key in /key in position 1 = no readings

Key in position 2 = readings in the attached file, namely fuel pressure at 430

Key in position 2 and cranking over = no change in any readings apart from current through injectors which rises to 900 ma

Does this help a bit more? Any idea which module might have the coolant temperature?

Cheers

[llywelyn1984]

my alternator went - same symptoms.
noticed smoke coming from it - they short circuit.
I did a diode test and it failed.