BlueStreakTDI
Well-known member
Hi all.
I'm having a gremlin situation here. My 2001 Jetta TDI was starting fine when I parked it in the garage. I returned from a 5 month work assignment and now It will crank fine but won't start. Battery is new and in good condition. When the ignition switch is turned on the glow plug light does not ever illuminate.
Things I checked so far.
- All fuses including main ones on top of battery
- Glow plug resistance, all are .8 or .9 Ohms
- Removed glow plug relay and bench tested. (Applied 12v and got good continuity between contacts) Looks like there might be a timer circuit in there as well but don't know how to test that. Reinstalled relay and can hear it click when key is cycled.
- unplugged coolant temp sensor and checked to see if 12v was getting to glow plug harness when key is turned on. Not getting 12v power to glow plugs. (only get .01 volt change when key is cycled.) Could this still be a bad glow plug relay? (Relay 109)
Next step will be to check if glow plug power is getting to the relay socket, and check for continuity from relay socket to glow plug harness but I suspect all that is ok.
It's my understanding that the ECM won't allow the engine to start when the glow plug circuit is not working.
The other issue i'm having is that I now can not get VCDS to talk to the ECM. I'm using the same setup as I did 6 months ago and everything worked fine. (I was able to access ECM with VCDS) I'm getting a "too many communications errors to continue" message. I can access some other controllers with my VCDS so I don't think it is an issue with my computer or hex com interface cable. Could there be a problem with my ECM or Instrument cluster?
Any ideas on where to go next?
Thanks!
I'm having a gremlin situation here. My 2001 Jetta TDI was starting fine when I parked it in the garage. I returned from a 5 month work assignment and now It will crank fine but won't start. Battery is new and in good condition. When the ignition switch is turned on the glow plug light does not ever illuminate.
Things I checked so far.
- All fuses including main ones on top of battery
- Glow plug resistance, all are .8 or .9 Ohms
- Removed glow plug relay and bench tested. (Applied 12v and got good continuity between contacts) Looks like there might be a timer circuit in there as well but don't know how to test that. Reinstalled relay and can hear it click when key is cycled.
- unplugged coolant temp sensor and checked to see if 12v was getting to glow plug harness when key is turned on. Not getting 12v power to glow plugs. (only get .01 volt change when key is cycled.) Could this still be a bad glow plug relay? (Relay 109)
Next step will be to check if glow plug power is getting to the relay socket, and check for continuity from relay socket to glow plug harness but I suspect all that is ok.
It's my understanding that the ECM won't allow the engine to start when the glow plug circuit is not working.
The other issue i'm having is that I now can not get VCDS to talk to the ECM. I'm using the same setup as I did 6 months ago and everything worked fine. (I was able to access ECM with VCDS) I'm getting a "too many communications errors to continue" message. I can access some other controllers with my VCDS so I don't think it is an issue with my computer or hex com interface cable. Could there be a problem with my ECM or Instrument cluster?
Any ideas on where to go next?
Thanks!