A6 2.0TDi Not Starting (Sometimes)

[baluachrach]

Hi wonder if anyone has any ideas re the problem I am having with my 2007 2.0 TDI. When you go to start the car nothing happens no engine turnover or clicking just silence although all dash lights look normal. Taking the key out and back in and trying again sometimes prompts it to start but sometimes this needs to be done multiple times before it will start. Doing this with both keys. Battery has recently been changed but this has made no difference. Problem also seems to be worse if the car has recently been driven.
Have had the car scanned and copied the results ( only shown the items that flagged a fault) The passenger door lock needs replaced as it is no longer unlocking but presumably this wouldn't affect starting? Any ideas would be gratefully appreciated

Chassis Type: 4F (4F0)
Scan: 01 03 05 07 08 09 0E 15 16 17 19 1E 37 42 46 47 4F 52 53 56
61 62 72 76

VIN: WAUZZZ4F58N015539 Mileage: 125900km/78230miles

01-Engine -- Status: Malfunction 0010
52-Door Elect, Pass. -- Status: Malfunction 0010

-------------------------------------------------------------------------------
Address 01: Engine Labels: 03G-906-016-BLB.clb
Part No SW: 03G 906 016 MH HW: 03G 906 016 MH
Component: R4 2,0L EDC G000SG 0948
Revision: --H05--- Serial number:
Coding: 0000072
Shop #: WSC 02325 758 00200
VCID: 75E1075F1C34EDB6B75-8020

2 Faults Found:
012369 - Starter Control; Returned Message
P3051 - 000 - 50 Implausible Signal - Intermittent
Freeze Frame:
Fault Status: 00110000
Fault Priority: 3
Fault Frequency: 45
Reset counter: 255
Time Indication: 0

Freeze Frame:
RPM: 0 /min
Speed: 0.0 km/h
Load: 0.0 %
Voltage: 11.86 V
Bin. Bits: 00101100
Bin. Bits: 0
(no units): 0.0

005510 - Engine Mount Solenoid Valves (N144/N145)
P1586 - 000 - Short to Plus - Intermittent

[Guest 2]

im no mechanic and may be wrong but i'd say your starter is on its way out? implausible signal/intermittent?

[royclark]

Could be - No communication with the access/start control unit (J518). Which may be caused by capacitor and or transistor damage with in the access/start control unit (J518).

PM sent

[baluachrach]

Thanks for the replies guys - any idea how hard the starter is to change on the A6? Presume it will be from underneath?

[royclark]

Yes. You will have to remove the heat shield and ATF pipes to remove the starter.

[B5NUT]

It's not the start motor, the start motor is a dumb device and has zero diagnostic capability so would not show up in a scan of the engine ECU. That is more to do with what roy is talking about. or it's the immo module (the one you stick the key in)

[baluachrach]

Thanks for the suggestion do you know of any checks I could carry out or best just putting to a specialist?

[royclark]

If its J518, I think it will be a new column. I hope i'm wrong, £££££££££££

[cassy]

Hi,

I recently has a similar problem with my car, does the DIS sometimes say press clutch pedal to start engine even if you are pressing the clutch pedal?

I thought it was my immo but turned out to be the clutch switch, we tested this by removing the switch and jumping the pins, there are only 2 pins so its easy.

If this works my car took a few turns to start without the switch but it only took 2 days to order from Audi (around £10-£15) and is easy to fit.

Hope this helps.

[baluachrach]

Hi Just logged in to update on my car - Sorry Cassy never saw your reply until just now. Car had been in to an independent and they tried a couple of things first relays then possible bad earth but in the end it turned out to be the clutch pedal switch! Funny thing was if you tried to start without foot on clutch the message would came up telling you to. Message would never come up if you had foot on clutch. So I incorrectly assumed the switch was ok. At least its sorted now and could have been worse.