S40 2001 total electrical shutdown

[JClaude]

Hello,

My car: S40, 2001, motor B4204 S2 gasoline, 136 HP, 155'00 km, manual shifting, very good shape, starts each day like new, never had a breakdown nor puncture!

Yesterday at night I was driving since 5-10 min when suddenly everything "Off" for about 10 sec. No more beams, radio, nothing, motor settled slowly down (fourth gear), everything "Off" ;-(((

I did nothing only kept driving and after 10 sec everything "On" again, the engine restarted without a hitch!

Ten minutes later, the same breakdown again!

Ten minutes later I arrived home without further problem!

Today I didn’t yet drove the car but I started the engine and like every day, no problem, like new, but…

Where should I begin searching for this problem?

I found the original Volvo wiring diagram (194 pages!) but at first look it seems rather complicated for an amateur!

Who has an idea?

Jean-Claude

[gazO2V40T4]

Originally Posted by JClaude

Hello,

My car: S40, 2001, motor B4204 S2 gasoline, 136 HP, 155'00 km, manual shifting, very good shape, starts each day like new, never had a breakdown nor puncture!

Yesterday at night I was driving since 5-10 min when suddenly everything "Off" for about 10 sec. No more beams, radio, nothing, motor settled slowly down (fourth gear), everything "Off" ;-(((

I did nothing only kept driving and after 10 sec everything "On" again, the engine restarted without a hitch!

Ten minutes later, the same breakdown again!

Ten minutes later I arrived home without further problem!

Today I didn’t yet drove the car but I started the engine and like every day, no problem, like new, but…

Where should I begin searching for this problem?

I found the original Volvo wiring diagram (194 pages!) but at first look it seems rather complicated for an amateur!

Who has an idea?

Jean-Claude

I personally would start by checking the battery terminals are connected and tight then check the earth strap on the car

If all is good I would then check the ignition switch to see if it’s sticking between positions

[JClaude]

Hello gazO2V40T4,

Many thanks for the answer!

I already did it: battery terminals are clean and tight and the same for the earth connection at both sides.

The ignition switch works well and comes always on Pos. II after engine started. As far as I know, if the switch would stay in Pos. III there would be nothing else working but engine starter.

Perhaps you have other idea.

Jean-Claude

[loely]

Ignition switch is a good start.
When running a car does not need a battery as the alternator provides the used current.

[Baffler]

Your symptoms are all too familiar with the engine wiring loom/harness which, being routed under the radiator, are subject to corrosion. Do a search for same in this section.

[V40T4R]

Originally Posted by Baffler

Your symptoms are all too familiar with the engine wiring loom/harness which, being routed under the radiator, are subject to corrosion. Do a search for same in this section.

Would bet this one....

[JClaude]

Hello V40T4R and Baffler,


Thank you to both, I apreciate your help very much!

I search the forum with these words: radiator wiring loom harness and found this:

https://www.volvoforums.org.uk/showt...loom%2Fharness

I am not sure the problem is here because as you can read in my post everything in the car (not only beams) was off during 10 seconds. Beams, radio, dashboard lights, tail lights also were off. The engine was also off 10 seconds but I didn't disengage and stayed with fourth gear, so after 10 seconds the engine restarted without a hitch!

The car following me saw the tail lights and the beams suddenly off and gave me a sign with its beams!

I imagine the wiring loom under the radiator has nothing to do with dashboard lights or radio or engine. Am I wrong?

The question is, what could produce such a problem although there is a battery and a generator always in circuit and moreover I did not even had to change a fuse!

A short circuit in the battery and the generator could not maintain the voltage???


Any new idea ?

Jean-Claude

[pierremcalpine]

what about a faulty CEM, or one that is not plugged in correctly? I'm just guessing here. Have you had any work done recently that would have necessitated the removal of the CEM down under the steering wheel?

[JClaude]

Hello Pierremcalpine,

Thank you very much for your answer!

Today I checked the ECM: I pulled out and then in all the for connectors attached to the ECM although they were in good place.

Everything works but I don't know if that solved the problem.

Wait and see, how long…

Jean-Claude