2002 Jetta CEL + P0763 Code

No noticeable change in running, but my 2002 Jetta (111k) has started giving a CEL. The code is a single P0763 (glowplug/heater #3). After looking up the info on this site, I checked the glow plugs - all at about 0.1 ohm. The harness looks good, and checked out at 12.7 volts across the board. I used DeoxIT in the boots. I checked under battery connection/fuse cover, and read 12.7 volts at each connection. After reassembly, it still throws the same code.

Is there something else to check? Do I remove the "harness" end of the harness and check and DeoxIT? Basically, is there something else to try before replacing the glow plug harness?

I'm no expert, but did you "erase" the original code after reassembly?

The harness is a weak link and may not contact the glow plug with perfect continuity. You might try cleaning the glow plug's contact point.

1) Yes, I erased all codes. BTW, the new CEL doesn't appear at startup, but several minutes later. Does that mean anything?

2) I didn't manually clean the glow plug posts, but continuity test was very, very low loss, and I used DeoxIT on the posts and in the harness contacts.

If you erase the codes but you didn't solve your problem, your cel comes on after the second or third start.

After I cleaned my harness and plug contacts, my problem went away for a few weeks. My latest attempt has lasted about that same time. I wrapped aluminum foil around the plug contact and jammed the harness on it. So far so good, but this is only a temp. fix until it warms up. I am going to make my own harness.

Forgot something...

After erasing codes and getting new CEL, code is now for cyl #2, instead of cyl #3 as before. Does this tell me anything?

It means your harness is the problem. Try cleaning it again and at the same time clean the plug contacts.

Thanks! I'll give it another try.

The last thing I did yesterday afternoon was clear the CEL again. Since then my wife drove to work and back and I have driven the car today. After 40+ miles, no new CEL. Maybe the DeoxIT just needed more time to work? Keeping my fingers crossed!