P38 '97 2.5 manual diesel DSE BECM fault

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WayneRR4x4

WayneRR4x4

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Had a battery drain issue, as regular readers of the forum will know.
Well, although I'm no expert after loads of research and testing, it looks like the BECM is not going to sleep, so, whats the next step?
New (2nd hand) BECM (and keys?)?
Send BECM away for a spanking (I mean, to get fixed)?
Find a friendly helpful P38 owner with a Nanocom who can sort it?

I'm hoping for option 3, but knowing my luck it will be (expensive) option 1 or 2 lol.
 
If the becm is at fault, no diagnostics will repair that.
To replace the becm & keys etc, is changing the identity of your vehicle & will cause future problems.

Can you get the readings of the three stage sleep process & publish them, then we might be able to help you.
The reading should be something like this,
1st stage reading 0.78ma 2nd stage sleep 0.52ma 3rd stage 0.02ma. The 3rd stage can differ depending on the age & series of the becm. On the earlier becm's the 3rd stage sleep can be as high as 0.05 & this is within acceptable limits.
 
nail on the head! My son has an old 1980 Suzuki LJ80, with very little in the way of security..rag top also.. It seemed like a good idea. Ok, its not the most desirable car in the world..but some idiots will take anything..
 
Last edited:
Mark Piercy said:
nail on the head! My son has an old 1980 Suzuki LJ80, with very little in the way of security..rag top also.. It seemed like a good idea. Ok, its not the most desirable car in the world..but some idiots will take anything..
Click to expand...

That would depend on the load needing to be handled. Remote relay load capacity would at least have to match the fuse capacity supplying the ignition barrel.
 
Mark Piercy said:
nail on the head! My son has an old 1980 Suzuki LJ80, with very little in the way of security..rag top also.. It seemed like a good idea. Ok, its not the most desirable car in the world..but some idiots will take anything..
Click to expand...

Get a high security switch from Maplin or similar and use it to break the low tension side of the ignition circuit. Mount it somewhere out of sight under the dash. Sorted.
 
+1 to RF intereference and door microswitches.

Also, check the ignition barrel is popping out all the way. Might need cleaning with contact cleaner, drying and then a squirt of graphite lube.

Plus check the door-handle is going in all the way.
 
brianp38dse said:
Are the door micro switches working properly, @martyuk did a test sheet for checking
found it
Click to expand...

This is awesome, only problem is, I'm still learning, so, a few questions.

1. When using a multi-meter on vehicles, what is the correct sockets (ports, plugs?) of the three to put the black and red leads into, I know for the sleep tests when putting the meter between the earth lead and the earth terminal on the battery it is the common port and the 10A port, is this for all testing?

2. Open / closed cct... what does this show on the multimeter screen?
 
Rick-the-Pick said:
If the becm is at fault, no diagnostics will repair that.
To replace the becm & keys etc, is changing the identity of your vehicle & will cause future problems.

Can you get the readings of the three stage sleep process & publish them, then we might be able to help you.
The reading should be something like this,
1st stage reading 0.78ma 2nd stage sleep 0.52ma 3rd stage 0.02ma. The 3rd stage can differ depending on the age & series of the becm. On the earlier becm's the 3rd stage sleep can be as high as 0.05 & this is within acceptable limits.
Click to expand...

I'm hoping it isn't the BECM, although someone who deals with them says if it is he can test it, and if necessary "clone" it (or a card within it?), reset the sleep mode and send it back and it should be fine.
I'll get the readings next time I can take it for a run to charge the battery enough, thought I'd found the electrical problem, a plug behind the LH kick panel was corroded inside, terminals were shot, LH door electrics didn't function.. rewired it, and the LH door electrics still don't function lol... if I didn't know any better I'd say this was a dummy vehicle built with faults in to test trainee RR mechanics... now I find I have water in the LH electrical wiring channel in the floor, probably coming from the feed to my rear washer which has stopped spraying water... I was warned when I first went on these type of forums about P38s... I am starting to wish I'd listened lol!
 
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