P38A Check Engine Light and Nanocom Connection Issues

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W

Westmoreland Rover

Member
Posts
13
Location
UK
Hi All,
I am new to this forum and I'm hoping that someone can help me out.

P38 refused to start the other day. Not cranking and check engine light not coming on. Reached for Nanocom to try and reset comms between BeCM and ECU. On doing so the Nanocom refused to link up and keep getting the error message that communications cannot be made with ECU. This doesn't happen with all functions and I can still retrieve, for example, details on the transmission etc but nothing much else.

The Nanocom is only a few months old and incidentally was bought to correct a no check engine light condition which miraculously rectified itself before the Nanocom arrived.

Over the course of the last three days I have done the following:
  • Battery checked and okay. Even tried battery off wife's car and still no joy.
  • All fuses and relays checked and okay, including those at BeCM;
  • RHS kick panel removed. Brown wire in large terminal block corroded beyond repair. Cut out and replaced. Earth point clean but taken apart, checked and refitted;
  • LHS kick panel removed. Red/grey wire in large terminal block corroded beyond repair. Cut out and replaced;
  • Two wire connecting blocks under header tank all checked and okay;
  • All relevant earth terminals under bonnet checked, cleaned and refitted;
  • OBDII connecter was replaced with new three months ago and all terminals are new. This was done at the time I bought the Nanocom
Despite this the Nanocom still won't communicate with ECU and still no check engine lamp.

The only major work which has been done over the last few weeks was replacing the headlining and the sunroof sliders cleaned and re-lubricated. The car has cranked over and started since and before this started the other day.

Any advice would be most welcome and before the thing drives me up the wall. Cheers.

P38 4.6L V8 1997MY GEMS
 
With no CEL on a GEMS means no connection between the ECU and BeCM.

If you have the problem before and it cured itself, then it is almost certainly a wiring issue.

I assume you have the ignition on when trying to communicate with the ECU, as it won’t do it with the ignition off as it does with the BeCM.

Have you had the ECU out and removed the plugs, checked and cleaned them? Might be worth looking at in case you have a corroded one or damaged wire there.
 
Thanks.
Yes, ignition ON when using Nanocom.
Had a quick look inside the ECU holder without removing plugs and no signs of anything untoward. I will however have a better look tomorrow.
I am also seeing ABS and AIRBAG fault warning messages in the LCD on dash. Forgot to mention on my original post.
Apart from that when I turn key to III just normal clicking of relays.
 
Welcome, I take it you have power to the obd socket? Pin 16 and pins 4&5 for ground.check the 5amp fuse in the engine bay fuse box, sorry I can't remember the number and I'm still in bed so can't check for you. Any smell of burning in the fuse box? They are prone to failure.
 
Westmoreland Rover said:
Hi All,
I am new to this forum and I'm hoping that someone can help me out.

P38 refused to start the other day. Not cranking and check engine light not coming on. Reached for Nanocom to try and reset comms between BeCM and ECU. On doing so the Nanocom refused to link up and keep getting the error message that communications cannot be made with ECU. This doesn't happen with all functions and I can still retrieve, for example, details on the transmission etc but nothing much else.

The Nanocom is only a few months old and incidentally was bought to correct a no check engine light condition which miraculously rectified itself before the Nanocom arrived.

Over the course of the last three days I have done the following:
  • Battery checked and okay. Even tried battery off wife's car and still no joy.
  • All fuses and relays checked and okay, including those at BeCM;
  • RHS kick panel removed. Brown wire in large terminal block corroded beyond repair. Cut out and replaced. Earth point clean but taken apart, checked and refitted;
  • LHS kick panel removed. Red/grey wire in large terminal block corroded beyond repair. Cut out and replaced;
  • Two wire connecting blocks under header tank all checked and okay;
  • All relevant earth terminals under bonnet checked, cleaned and refitted;
  • OBDII connecter was replaced with new three months ago and all terminals are new. This was done at the time I bought the Nanocom
Despite this the Nanocom still won't communicate with ECU and still no check engine lamp.

The only major work which has been done over the last few weeks was replacing the headlining and the sunroof sliders cleaned and re-lubricated. The car has cranked over and started since and before this started the other day.

Any advice would be most welcome and before the thing drives me up the wall. Cheers.

P38 4.6L V8 1997MY GEMS
Click to expand...

Some Nanocom mudules require ignition in position 2, some engine running and some work with key out. Nancom manual will help you there.

RAVE and also the Nanocom manual will show you which pins are used with which module in the Nanocom so you can check continuity. Fuses are a good place to start though.

I'd check the earth points too.
 
Thanks for everyone's advice. So today I have checked:
Battery leads and connections - all okay
Fusebox okay and no smells of burning
All fuses are sound
Connectors to ECU are in perfect condition with no evidence of dampness or corrosion
All earth points okay
Checked ground to pins 4 & 5 on OBD and both are okay

The only issue I can find is there is no ground on pin 16 (brown wire) of the OBD.
 
Westmoreland Rover said:
Thanks for everyone's advice. So today I have checked:
Battery leads and connections - all okay
Fusebox okay and no smells of burning
All fuses are sound
Connectors to ECU are in perfect condition with no evidence of dampness or corrosion
All earth points okay
Checked ground to pins 4 & 5 on OBD and both are okay

The only issue I can find is there is no ground on pin 16 (brown wire) of the OBD.
Click to expand...
Pin 16 should be power.brown wire from fuse box passes through the bulkhead under the heater where I think it has a splice in it then continues to the obd socket, from memory.
 
Of course, there is the possibility that the Nanocom is at fault. Any chance you can see if you can find another car to try it on?
 
Make sure you have the OBD cable already connected and screwed into the Nanocom before inserting it into the RR’s OBD port.
You can blow an internal fuse inside the Nanocom if you insert the OBD cable into the RR’s OBD port first and then connect the Nanocom.
 
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