2.0TDI Multitronic Intermittent Starting.

[STAGMAN]

Help please. Several times recently the engine turns over and won't start. Usually it fires on the second or third attempt. Tonight it wouldn't start and I noticed the the gear display had flashing red blocks around the symbols.

scanned with VCDS with the following codes:

auto trans 2 faults 005975 supply voltage P1757 open circuit intermittent and 049408 no communications with engine control module U0100 intermittent.

ABS 01314 engine control module 004 no signal intermittent

instruments, xenon range and immobiliser as ABS above.

navigation 02261 data medium. 014 defective intermittent.

central convenience 01366 opened due to crash signal.

fault code 01314 seems a common thread but what is the source of problem?

many thanks in advance.

John

[a8 tech]

Hi replace the engine control unit voltage supply relay

location osf E box in plenith chamber, abs and gearbox control unit losing coms with engine ecu due to voltage drop from engine ecu supply relay secondary circuit (pitted contact)

Around £25

[STAGMAN]

That's brilliant. Thank you!!!

i feared it was going to be another new gearbox.

john.

[STAGMAN]

Just checked with local main dealer and they list the following relays in plenum chamber box.
Fuel pump 395
auto gearbox 395. ( had new one of those 6 months ago)
secondary air pump 373
Glow plug 457
closed contact engine ????? 614.

could it be the last one??

I thought it might have been a 508 but apparently not in this car.

Thanks again.

John.