Question about 2000 Volkswagen Jetta TDI
My TDI has had intermittent glow plug light issues - no lights come on, so car will crank but won't start. Thought glow plug relay was going bad, easy fix, so did that. Worked fine for a few days, then started up doing the same thing again. Now no glow plug light, car cranks but acts like getting no fuel or spark. Have checked glow plugs - all good. Good voltage on battery. Tried OBDII scanner, but won't link up with ECM. Have no clue where to go next. Please help!
I don't have the solution but a possible help in diagnosing. If you remove the water temperature sensor connector from the sensor, the glow plug light should stay on when you go to start the car. Try leaving it on for 15 seconds and then start the car. If it starts right away, it is your sensor. If it doesn't, the good luck.
The sensor is located on the right side of the engine near the top, at the back. It is in the coolant fitting directly behind the hose from the rad, just left of the thermostat. Be careful to disconnect the wires, and not remove the sensor, or you will loose a lot of coolant. The sensor is held in by a separate plastic clip, and the harness just has a little built in clip on the side. Hope you have small hands...
Posted on Jan 06, 2009
Thanks for all the pointers. The issue turned out to be a corroded wire which connects the Power Relay's primary circuit to the ECM. So symptoms appeared to be a bad power Relay. When I bench tested the power relay and realized it was OK, knew there was an issue with the primary circuit. tested voltage and was low (approx 6V) available to connector 86 on the relay; so definite drop somewhere.
Using Bentley diagram, I traced wire back from Power relay to position on ECM and sure enough there was a pinhole in the wire's plastic casing. Plastic casing appears to have rubbed against the ECM housing creating a small pinhole allowing moisture in. The wire was 95% corroded, and hanging together with a couple wire strands! Cut out the bad section of wire and resoldered and everything working again as it should.
Thanks for the help!
Posted on Jan 19, 2009
My problem was the ECM ( computer). Most often this problem is caused by the 109 relay, a much cheaper part.
Posted on Jan 07, 2009
Very common problem in our shop. I bet you it is the main power relay located under the dash on the driver's side. That relay failure is consistent with your symptoms.
Posted on Aug 17, 2008
Hi, You'll both find the best way is to get the fault codes read, using VAG-com, and once armed with them start Googling or go to http://www.bentleypublishers.com/tech/vw/vw.dtc.table.htm
where you'll get some pointers. D
Posted on Aug 15, 2008
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