Help - where to go next

[johnsail]

Hi. Have had my 2010 reg C5 Tourer 2.0 Hdi since 2015 with very, very few problems that could not be sorted by my local garage. However a recent electronic problem is causing some grief. The car drives 'as normal' with no obvious signs of a problem other than . . . . . .

SYMPTOMS
On start up the car displays a warning - ENGINE FAULT REPAIR! and the engine warning light is illuminated. The warning goes out leaving the engine warning light on and SERVICE is displayed. A couple of seconds later a message is displayed indicating a problem with the air bag / seatbelt pretensioner. This then goes out and I am left with (a) the engine warning light on (b) the SERVICE light on and (c) the pretensioner warning light on in the display above the rear-view mirror
My local garage did not feel confident that their equipment was able to pinpoint the problem.

Action thus far:- Took it my local Main Dealer in Basingstoke for a diagnostic analysis who (a) have plugged in their black box and printed the start of test report and then (b) done 6.5 hours of manual checks - meters, scopes etc - and supplied a hand written work sheet indicating all necessary manual tests had checked out OK and indicating a new ECU was required @ £2400 (not sure whether this included VAT).
They charged me several hundred pounds for this diagnosis.

I was left with a feeling of no confidence with the Main Dealer so sent ecu to Car Techtronics who cloned my details on to a good ecu and sent it to me. The same problems are exhibited so I am assuming that there is not / was not a problem with with my original ecu and, as agreed, I have sent the Car Techtronics ecu back to them and I await my original being returned to me.

I understand that there are three main electronic units on the CAN bus but only the ecu is examined electronically. This actually surprised me as I had assumed ( Yea! we know what that makes of you!) that software checked out the entire system.

Where do i go next?

John

[wheeler]

What ECU are we talking about here? The airbag ECU or engine ECU?
6.5 hours, ouch!

[GiveMeABreak]

Can you please provide your VIN so we know which engine we are referring to as you could have the DW10BTED4 or the DW10CTED4 along with any fault codes from the diagnostic that they undertook.

[johnsail]

Hi Sorry for delay - trouble with log in but sorted now.
VIN:- VF7**************[VIN obfuscated, can be read by forum staff]
Main Dealer diagnosed Engine ECU needs replacing.
Report at start of diagnostics:-
P0215 MAIN RELAY
Cause Local
Status Intermittent
Characterisation of the fault Poor operation of the relay, the ECU is not being supplied as it should be

List of associated variables:
Battery voltage 11.45 V
+IGN NO
Status of power relay NO
Main relay status NO
Engine status Cut or stalled
Engine speed O Rpm
Mileage 91293 Km
Vehicle speed 0 Km/h

U1118 Intersystems CAN
Properties
Cause Distant
Status Permanent fault
Characterisation of the fault Absence of communication with the BSI

List of associated variables:
Battery voltage 14.06 V
+IGN status Yes
Status of the power relay Yes
Main relay status Yes
Engine speed 800 Rpm
Mileage 91293 Km
Vehicle speed 0 Km/h
Accelerator pedal position 0 %

The hand written report from mechanic reads:-
'fault code U1118 no comms with BSI
carried out guided fault finding - checked intersystem
can bus system + connectors -
all checks correct - fault
finding result is too replace ECM'

That's all I got for my money plus the £2400 estimate for repair.

[GiveMeABreak]

Ok, so these are the full descriptors for those fault codes.

Fault Code:	P0215
Description of Fault:	Principal relay : Incorrect operation of the relay, the engine management ECU does not have the correct power supply. Engine ECU still supplied for 1 s despite a request for cutting of its supply. Loss of supply of the engine ECU for 1 s without a prior request being detected, due to an incorrect value memorised at the following wake-up.
Conditions for Fault to clear:	Driving with the engine hot for 5 minutes
Downgrade Modes whilst Fault is active:	None
Symptoms:	Starting problem
Suspect Areas:	Electrical harness Connectors Principal relay

U118 has no further info short of what has been stated - Inter systems CAN.



This won't be the first time I've heard of Engine Fuse box issues on this engine variant (DW10CTED4). I'm wondering if it is worth checking all the power connections from the engine fuse box (PSF1) to the BSI.

If some part of the the BSI isn't being powered via the engine fuse box, then it could result in communications issues with the other ECUs. So checking the Maxi Fuses, and seeing whether there is power supplied to the BSI may be a start. If the principle relay is faulty inside the engine fuse box, then that is far less expensive to replace than whatever the garage wanted for the BSI...

1320 is the Engine Management ECU
BSI1 is the BSI
PSF1 is the Engine Fuse Box.

BM08: engine fuse box battery + output
BM04: engine fuse box battery + output

9000: High Intersystem / Can bus
9001: Low Intersystem / Can bus

[johnsail]

Thanks Marc. I expect return of ECU next week so will be able to progress then.

[wheeler]

My first thoughts as I was reading this were also an under bonnet fuse box fault however I would be absolutely amazed if this was in a main dealers and one had not already been tried in the 6 & a half hours investigation time. Most dealer techs would normally have a spare test unit for an non coded part like this or at least have access to one for testing purposes from a forecourt car etc.

[GiveMeABreak]

I agree that's a lot of testing time without seemingly to mention the engine fuse box.

It may be worth a punt at a replacement fuse box, which you can get for £185 new here:

https://www.ebay.co.uk/itm/273812502562

Keep it well protected and clean whilst seeing if you can connect it up without fully fitting it. If that gets rid of the messages in the dash then great. If not, you should be able to return it within the 30 days for the cost of return postage.

[wheeler]

Surely a dealer wouldn’t accept returns once the box has been opened unless the part is faulty or not as described?
Remember the main positive connection is bolted & attaches to the cars maxi fuse box so you wouldn’t really be able to just plug it in.

[GiveMeABreak]

Just a thought and why I mentioned that as long as it is retained in clean condition. I'm just going on their 30 day returns policy for distance selling. You are entitled to open the box for inspection, but if it's gong to get scratched up then maybe not. If it doesn't resolve the issue then you can at least rule that out and re-sell on the fusebox for a few quid less.

Seems the BSI has come crashing down on this model from a few years back - with an exchange BSI now for £263 - or a new one for £440! So don't know where they are getting the £2400 from....

[wheeler]

Seems the BSI has come crashing down on this model from a few years back - with an exchange BSI now for £263 - or a new one for £440! So don't know where they are getting the £2400 from....

I think it's the injection ECU that they are saying is the problem These are up to £1660 just for the part or just under a grand for an exchange one.

[myglaren]

Surely a dealer wouldn’t accept returns once the box has been opened unless the part is faulty or not as described?
Remember the main positive connection is bolted & attaches to the cars maxi fuse box so you wouldn’t really be able to just plug it in.

When I have bought electrical/electronic bits from the dealer, they don't accept returns at all.
Probably used to people connecting them incorrectly, ruining them then trying to claim that they were defective out of the box.

[GiveMeABreak]

I didn't see anywhere obvious that the ebay seller was a dealer - but if using ebay, then they must comply with ebay's T&Cs and the seller's returns policy which simply stated 30 days.

[myglaren]

I was just passing on my experience at a dealer's. eBay could be completely different.

[GiveMeABreak]

I just saw Wheeler's post mentioning a dealer - but it isn't obvious from the listing that I can see Steve.