2.5 DSE Accelerator not responding no more

This site contains affiliate links for which LandyZone may be compensated if you make a purchase.
Regarding your SELECT NEUTRAL fault... I would check the 'Low Range' switch in the gear shift assembly. It's buried down under the H gate, but you can test it with a multimeter at the transfer case ECU - Pin 33 of C1319. Testing it on continuity, with one multimeter pin on ground and one on pin 33, you should have no connection when the gear shift is in High range, and a connection to ground when the shifter is moved over to Low range.

I've seen it a couple of times where the switch has become gummed up and it sticks, so the transfer case ECU keeps thinking you want to switch range - which if it isn't in Neutral, you will get a SELECT NEUTRAL message up on the dash all the time. Failing that, have you tried swapping the transfer case ECU over from your parts vehicle? as the early ones are known for going pop, and it could be something internal to that.

Before the BECM/throttle pedal issue, did you have any issues with the gearbox indicators on the H gate or the instrument cluster not matching up what gear the shifter was in?

The throttle position sensor is a weird one - none of the connections on it go anywhere near the BECM - they go direct from the sensor to the connector under the bonnet and to the engine ECU.

I've just looked at the connector pinouts and the 2 grey connectors you show as having shorted pins on are all power outputs from the BECM - and again none of these are actually connected to the engine ECU that I can see. Most of them are outputs to the rear lights/door functions, power to the courtesy lights and RF receiver, FM aerial amplifier, Rear view mirror dip ignition feed, and RHF outstation/window/door amp power feeds.

The engine ECU diagnostic feed goes through one of the connectors in the RHF footwell behind the kick panel - it could well be worth checking that for a corroded connection. If you can get communication to the engine ECU, then you can swap the other ECU in and read the immobiliser code from that, and then program that into the BECM to allow it to start, and then check the throttle on that other ECU.

At this stage, I'd like to say you possibly got lucky and haven't killed anything on the BECM, but won't know until there are other tests done. I would ideally work on trying to get diagnostic communication to the engine ECU, as that will allow you to swap the ECU and then narrow down the throttle issue. Out of interest - can you talk to the ABS ECU on diagnostics? The BECM, HEVAC, Gearbox ECU, Engine ECU, and ABS Ecu's all use the same data lines - the all the ones you can talk to go through a splice in the dash wiring loom, but the ABS and Engine ECU go through the kick panel connector (which is known for corroding and having bad connections), so if you can't communicate with ABS either, then I'd start there. Once you can get comms to the engine ECU, swap it over, recode the BECM for the immobiliser code in the replacement ECU and see if the throttle works.

I haven't done much with the Diesel P38's, but once you get the comms to the engine ECU, you might even be able to read the live data in the current ECU, and see what it thinks the throttle position sensor is doing.
 
martyuk said:
Regarding your SELECT NEUTRAL fault... I would check the 'Low Range' switch in the gear shift assembly. It's buried down under the H gate, but you can test it with a multimeter at the transfer case ECU - Pin 33 of C1319. Testing it on continuity, with one multimeter pin on ground and one on pin 33, you should have no connection when the gear shift is in High range, and a connection to ground when the shifter is moved over to Low range.

I've seen it a couple of times where the switch has become gummed up and it sticks, so the transfer case ECU keeps thinking you want to switch range - which if it isn't in Neutral, you will get a SELECT NEUTRAL message up on the dash all the time. Failing that, have you tried swapping the transfer case ECU over from your parts vehicle? as the early ones are known for going pop, and it could be something internal to that.
.
Click to expand...
Now this could explain why mine won't go into low. Cleaned the connectors underneath and checked the motor, all good. Haven't spent a vast amount of time on it but this sounds promising.
 
Just had look is only manual R380 up to vin WA 408338
0EE5403E-788B-4492-87F4-870C9A3F4C58.jpeg
 
martyuk said:
Regarding your SELECT NEUTRAL fault... I would check the 'Low Range' switch in the gear shift assembly. It's buried down under the H gate, but you can test it with a multimeter at the transfer case ECU - Pin 33 of C1319. Testing it on continuity, with one multimeter pin on ground and one on pin 33, you should have no connection when the gear shift is in High range, and a connection to ground when the shifter is moved over to Low range.

I've seen it a couple of times where the switch has become gummed up and it sticks, so the transfer case ECU keeps thinking you want to switch range - which if it isn't in Neutral, you will get a SELECT NEUTRAL message up on the dash all the time. Failing that, have you tried swapping the transfer case ECU over from your parts vehicle? as the early ones are known for going pop, and it could be something internal to that.

Before the BECM/throttle pedal issue, did you have any issues with the gearbox indicators on the H gate or the instrument cluster not matching up what gear the shifter was in?

The throttle position sensor is a weird one - none of the connections on it go anywhere near the BECM - they go direct from the sensor to the connector under the bonnet and to the engine ECU.

I've just looked at the connector pinouts and the 2 grey connectors you show as having shorted pins on are all power outputs from the BECM - and again none of these are actually connected to the engine ECU that I can see. Most of them are outputs to the rear lights/door functions, power to the courtesy lights and RF receiver, FM aerial amplifier, Rear view mirror dip ignition feed, and RHF outstation/window/door amp power feeds.

The engine ECU diagnostic feed goes through one of the connectors in the RHF footwell behind the kick panel - it could well be worth checking that for a corroded connection. If you can get communication to the engine ECU, then you can swap the other ECU in and read the immobiliser code from that, and then program that into the BECM to allow it to start, and then check the throttle on that other ECU.

At this stage, I'd like to say you possibly got lucky and haven't killed anything on the BECM, but won't know until there are other tests done. I would ideally work on trying to get diagnostic communication to the engine ECU, as that will allow you to swap the ECU and then narrow down the throttle issue. Out of interest - can you talk to the ABS ECU on diagnostics? The BECM, HEVAC, Gearbox ECU, Engine ECU, and ABS Ecu's all use the same data lines - the all the ones you can talk to go through a splice in the dash wiring loom, but the ABS and Engine ECU go through the kick panel connector (which is known for corroding and having bad connections), so if you can't communicate with ABS either, then I'd start there. Once you can get comms to the engine ECU, swap it over, recode the BECM for the immobiliser code in the replacement ECU and see if the throttle works.

I haven't done much with the Diesel P38's, but once you get the comms to the engine ECU, you might even be able to read the live data in the current ECU, and see what it thinks the throttle position sensor is doing.
Click to expand...
I can confirm that live data from the throttle position sensor is available in Faultmate I believe Nanocom
 
Mine has the recall problem, i even have a replacement plastic bit but unless the box needs to come out again it is not happening, i have got round it with a little jumper cable plugged in to the neutral switch plug as long as you remember not to press the low range button unless its in out of gear and clutch down no problems.
 
mine had it done and yet not great at current age. Lubrication was main issue. Itl go in/out but have to select neutral while holding gearstick in the sweet spot between 3rd / 5th
My belief is use it or lose it. Standing fur years what made it started playing up.
 
martyuk cheers bud., thanks for taking the time to write all that.

I can talk to the HEVAC, the BECM, the EAS and the transmission ECU.
I cannot talk to the airbags or the Engine ECU.

On the nanocom I went through every setting and test I could in the BECM section, it all seems to be working fine.

You are correct, on the dash it will sometimes say that its in Low when actually its in High. It wont correct itself unless I restart the engine.

I'll run that continuity test tonight on the transfer box ecu, also i'll try the other transfer-box ecu.

I went to see the local auto-electrician and if I cant get it going, I'll send it to him next week.
 
Last edited:
I cleaned the three connectors in the drivers foot-well. I did indeed find corrosion.
I can clean the pins but I don't really know how to clean the sockets. I think a better job might be to replace the connectors altogether.

upload_2020-6-17_9-41-0.png


upload_2020-6-17_9-41-43.png


upload_2020-6-17_9-42-9.png



Seeing this I became very optimistic, alas, it didn't make a difference, still no comms with the engine ECU.
I'm gonna follow the wiring along and see what I can discover.

I keep getting a message saying alternator fault. I might swap on my spare alt.

Have opened and am looking at, the electrical section in RAVE, for the transfer box ecu pins, will try that this evening
 
ned_ said:
I cleaned the three connectors in the drivers foot-well. I did indeed find corrosion.
I can clean the pins but I don't really know how to clean the sockets. I think a better job might be to replace the connectors altogether.

View attachment 212468

View attachment 212469

View attachment 212470


Seeing this I became very optimistic, alas, it didn't make a difference, still no comms with the engine ECU.
I'm gonna follow the wiring along and see what I can discover.

I keep getting a message saying alternator fault. I might swap on my spare alt.

Have opened and am looking at, the electrical section in RAVE, for the transfer box ecu pins, will try that this evening
Click to expand...
I cut the connectors out and solder the wires one by one and insulate with glue filled heat shrink.
Alternator fault may be the alternator or even the earth strap from engine to chassis. If it's the alternator, it will be worn brushes, easy fix, replace with a new regulator/brush assembly with a set point of 14.7 volts. Mobiletron do one at a very reasonable price.
 
Last edited:
Yes I think I read that the earth strap is problematic somewhere online. The alt is still making 13.5 volts or thereabouts, it is working.

Your process regarding heat shrink and glue sounds like a go-er, appreciate the tip.
 
ned_ said:
Yes I think I read that the earth strap is problematic somewhere online. The alt is still making 13.5 volts or thereabouts, it is working.

Your process regarding heat shrink and glue sounds like a go-er, appreciate the tip.
Click to expand...
Even if the alternator is original, it should make a minimum of 13.8 volts. There is most likely a bad connection somewhere, earth strap being one possibility. For modern battery's, the regulator needs changing for a 14.7 volt set point.
 
The throttle pot is connected directly to the engine ECU it does not go through the BECM. Links to BECM from engine ECU are to allow it to distribute engine speed readings to other systems. Gearbox ECU, low range ECU, EAS etc.
 
The alternator light is driven by a Brown/Yellow wire that goes from the alternator to the BECM... Guess which connector it goes through? Correct... one of the ones in your picture that are green and horrible,

I also cut them out and solder the wires together and heatshrink them. Cleaning those connectors worn't do much in that state, as I've seen plenty where the corrosion is through the pins at the crimped end where the wire comes in. Pink/Red and Light Green/Red are the wires that the diagnostics go through.

It's worth getting those connectors cut out and wires soldered before trying to trace much more or worry about other faults - only as there are LOTS of different functions that go through these connectors.

Whilst you're there, also chop out and solder the chunky wires in the brown connector together - they are the main feeds from the fusebox to the blower motors. If that brown connector is corroded, then the extra resistance of the corrosion can cause more current draw, which doesn't help the fuse box under the bonnet - as over time with extra current draw the relays get hot and it damages the fuse box.

Let us know the state of things once the connectors are done - hopefully you will be able to talk to the engine ECU then, and we can start narrowing down some of the other niggles....

If you get Low on the dash occasionally, then definitely worth checking out the microswitch in the gear shift mechanism.
 
You must log in or register to reply here.

Similar threads

TimoTS
Range Rover classic 3.9EFI no oil visible under oil fill cap.
Replies
19
Views
626
aj1954
aj1954
DollyBird
Engine disabled, keys not working, tried the guide “Re-synching the Range Rover P38 diesel engine with the Solved - BECM using a Nanocom” no luck
Replies
9
Views
1K
DollyBird
DollyBird
T
P38A P38 DSE Manual (non-EGR) No turbo boost
Replies
7
Views
857
Grrrrrr
Grrrrrr
Joss155
P38A 2.5 dse becm syncmate
Replies
17
Views
2K
Joss155
Joss155
A
Lower Tailgate Switch Not Working L320 Sport 2008
Replies
12
Views
415
adriansj
A
Back
Top