P38A Engine disabled

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Thanks all,

I've hopefully got someone coming to have a look on the weekend. He works for a Land Rover specialist and comes highly recommended.
Rick-the-Pick said:
Tell me if I'm correct.

You had a flat battery, you used the EKA code successfully, once only, & after turning off, you cannot get access again. All doors unlock when key is turned in the door?

This is either a failed door lock, or a becm problem.
I've come across this many times in the past. The sure sign is this, no communications with the becm with any diagnostics.

We can sort this out.
Click to expand...

Thanks Rick,

Will probably be in touch!!!!!

Regards

Steve
 
We're here if needed.
If you can get diagnostics to the becm, get the diagnostics to activate the door locking & unlocking procedure & this will tell you if the door locks have a problem. Then go for re-synchronization. Fingers crossed that this may sort everything out.
If you get no diagnostics to becm, but can access all other modules, it's your becm with the problem.
 
Cannot contact the bloke who was going to have a look-so will now send the Becm to Rick along with the engine ECU.

Just a quickie-where is the engine ecu?

REgards

Steve
 
Have you actually tested the RHF door latch microswitches?

Yes, *could* be a BECM problem, for sure - but the tailgate 'locking' isn't controlled by the BECM.
The tailgate latch motor has a permanent 12V feed to one side of it (from F15 - which also feeds the rear loadspace lamp, RF receiver, rear door amplifiers, and some of the other interior lights.

The first check I would be making is that you have 12V at the tailgate motor. If you have 12V there, and it isn't intermittent, or doesn't cut out, or come on after 'a delay' then I seriously doubt the issue is in the BECM.
Other than supplying the power to the motor the BECM has no control over the tailgate motor as the grounding for the motor comes from the CDL switch in the RHF door latch (when it's unlocked) and then through numerous connectors (any of which could have a slightly corroded pin in them!) and then to the tailgate switch.

The tailgate switch then completes the ground circuit to actually make the motor work and unlatch the tailgate..

Personally, I think it's worth checking for power at the motor first, and then checking the continuity of the ground, via the switch in the tailgate, and the door latch switch.

If you are wanting to send the BECM/Engine ECU off for testing then fair enough, but I haven't seen results of any other testing you can do with a multimeter at home yet.
Depending on the vehicle you have depends on where the engine ECU is.

GEMS Petrol, and Diesel all have the engine ECU behind the battery in a compartment. Bosch (Thor) petrol has is in a plastic case behind the EAS box/cruise control module, yes.
 
Thanks!

I'll get the meter out in the morning.

The only thing throwing me is the the recurring delay on the boot-a dodgy connection would not result in a fixed delay. It's got to be connected to the interior light delay-common connector/ground?
Regards Steve
 
stevebrookman said:
Thanks!

I'll get the meter out in the morning.

The only thing throwing me is the the recurring delay on the boot-a dodgy connection would not result in a fixed delay. It's got to be connected to the interior light delay-common connector/ground?
Regards Steve
Click to expand...

Yes, interior light has delay hence suspected common ground issue.
 
I had forgotten about the delay being with the interior lights...

The thing is though with the interior lights is that they are low side controlled - IE they have a permanent +ve feed and the BECM controls the -ve side to provide them with a ground, and thus conduct current and operate.

Keep the meter on the +ve feed to the tailgate and try operating the interior lights (or get an assistant to press the button in the front dome light button to trigger the interior lights on/off) and see if the voltage changes

The only way I can think of that the tailgate operates with the interior lights out is that somehow the wiring to the tailgate has been messed with and power to the motor has been taken from the control side of one of the interior lights (which is ground when the lights are on - so the motor wouldn't operate with the other side grounded through the door latch - and then when the lights go out - the floating voltage on the '-ve' side of the interior lights is now at battery voltage, so pressing the button connects the circuit and pop goes the tailgate.

Doesn't fully explain the having to wait to open the other half - unless the triggering of the first part puts a reverse load on the device that does the interior lights, and this then goes into a protection mode and then resets...

It's one of the tough ones of being hard to diagnose without it in front of you - but measuring the voltages found will be handy (and check/clean the ground point) as it might give more of a clue as to whether the issue is on the power supply side, or the switch/grounding side of the tailgate circuit.

If you get normal looking voltages with the motor disconnected, then maybe try a second test, but do it with the latch/motor and switch plugged in , so the circuit is complete and see if/what variations there are in readings.
 
Thanks Marty and Grrrr,
I'll get my trusty multimeter out and investigate today or tomorrow-I'll also check the door microswitches.

I think there are two separate problems-the lights/boot and the loss of comms with the BeCM-Ricks description of what is happening is spot on.

Was due to go away tomorrow-but this is the first time the car has let me down in 11 years-which on the whole is not too bad!!-for any car let alone a P38!

Many thanks again for the advice.
Regards

Stecve
 
You could acquire another drivers door lock mechanism & plug it into the loom in the door.
You can manipulate it by hand & see if it makes a difference. This test takes as long as it take to remove the door card.
 
Thanks Rick,

Had a look at the tailgate lock. The earth side is working fine-but there is no permanent 12 v feed to the other side.
Fuses fine.
Pressing the dome light front button has no effect on disabling/enabling the interior lights. The front map reading lights also fail to work-checked bulbs and tracks -all good.

Will have another play
 
Had another fiddle. I removed the two wires from the lock mechanism on the lower tailgate-I think its to tell if tailgate closed.

Still have a lights out delay to open the top part-but now seems that power is constant after the lights delay and I don't have to wait for the lower tailgate to open.
 
Power is constant unless the door is opened and interior delay comes on. Then you have to wait until lights go out.
Another funny thing-according to the manual fuse 15 controls the courtesy lights, handset receiver, loadspace light, rear wiper, subwoofer rear audio amps-but when I pull it it kills power to the tailgate lock.
Tailgate lock is fuse 14
 
stevebrookman said:
Power is constant unless the door is opened and interior delay comes on. Then you have to wait until lights go out.
Another funny thing-according to the manual fuse 15 controls the courtesy lights, handset receiver, loadspace light, rear wiper, subwoofer rear audio amps-but when I pull it it kills power to the tailgate lock.
Tailgate lock is fuse 14
Click to expand...
Tailgate actuator is fuse 15. Fuse 14 is fuel flap release actuator, this is only powered with ignition off..
 
Thanks Wammers.

I'm going to contact Rick and get it off to him. There is definitely something up with the BeCM.

Regards

Steve
 
Rick has worked his magic but has suggested that I need a new door mechanism-I assume this is the microswitches/servo?

Does this come as a unit and where could I buy it from?

I'd rather fit one before I put the BeCM back.

Regards

Steve
 
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