2006 Jetta TDI PD, No Start, No MIL, No Glow Plug Light, cranks OK.

[Jeffcee]

Hello All,

The symptom list is:
1) Engine cranks but does not fire.
2) MIL and GP lights never go on.
3) VCDS cannot communicate with ECM.
4) VCDS can communicate with other on board modules, some of which report that they cannot communicate with ECM.
5) Relay 109 is replaced and operating.
6) Fuel pump relay does NOT operate.

The car:
2006 A4 Jetta Wagon TDI PD, 1.9L. 5 speed manual. Canada delivery.
Original owner. 55,000 Km. No recent changes.
100% stock, no reprogramming or biodiesel.

I posted about 5 days ago and got a lot of help. Many thanks. That post is here, FYI:
http://www.eurodrivers.ca/forums/sho...-TDI-no-start&

The situation is clearer now. I stated before that the glow plug light does not come on with the ignition, and recently I also noticed ( finally ) that the MIL light never comes on.

Details: A fellow forum user gave me a VCDS scan ( Thank You "S" ). The ECM could not be found with his unit. We were able to connect to the instrument cluster and a couple other on-board modules which reported fault codes stating that the modules could not communicate with the ECM.

Seems to me the ECM is not working for whatever reason.

So I’ve spent the last few days tracing wires and checking the voltage supply to the ECM. Interestingly enough, relay 109 DOES operate and it DOES supply voltage to fuses 32, 34 and 43 as it should. What’s interesting is that relay 109 is engaged by the ECM, suggesting that the ECM does have at least enough brainpower to close that relay. Go figure.

I also verified that the ECM is NOT operating the fuel pump relay as it should. Go figure.

I pulled the ECM connectors and traced the continuity of the power supply wires back through the ignition switch all the way to the battery. Also did a continuity check of the grounds. All seems good. Put it together, same problem.

At this point I am convinced that the ECM is no-op. I’m ready to hand it over to the dealership as the ECM is still covered by the Canadian emissions warranty. ( Dealership already confirmed this ).

I made a last search through the posts and procedures. I couldn’t find a similar problem.

Finally, I’m making this last post in the hopes that perhaps someone can help.

Anyone ever lose an ECM or had a similar set of symptoms?

Thanks to all again,
JC.

[Geobmx4life]

Re: 2006 Jetta TDI PD, No Start, No MIL, No Glow Plug Light, cranks OK.

Wow...shitty luck. have you posted this on TDI club? There are alot of threads regarding the ECU and similar problems. Good luck.

[skottieboy90]

Re: 2006 Jetta TDI PD, No Start, No MIL, No Glow Plug Light, cranks OK.

my roommate had the same issue, after he changed his oil. he replaced the ecu and it started again then he plugged his old one back in and it ran fine

[aliencurv]

Re: 2006 Jetta TDI PD, No Start, No MIL, No Glow Plug Light, cranks OK.

if you have power to the ecu, and it vcds will not communicate with it.... then the ecu is toast. you only need power and gnd for the ecu to respond to vcdsdsds commands. when i have an ecu on the bench, it responds with just power and gnd.

now, your only option to check is the ignition switch. the ecu will not respond unless the ignition is in run position (because it doesn't get power until then).

my old s4 (rodmans car) had the ecu die on it. i went through that whole song and dance until i figured out how easy it is to power-up a working one.

[Jeffcee]

Re: 2006 Jetta TDI PD, No Start, No MIL, No Glow Plug Light, cranks OK.

Hello all,

In the end it was the ECM.

I towed it to the dealer who, after 2 hours diagnostics, agreed that the ECM was a fault.

I used the dealer because the ECM was one of three parts still covered by the emissions warranty. Cudos to VW for honouring that, as they might have made the argument that the problem is not related to emissions.... ( I was bracing for that one, practising my answer, like "OK. Please conduct an emissions test and let me know how it goes" ).

Anyway, thanks to all for the input. I hope this thread will help others in the future.

Jeff
Calgary AB.