what2be Posted September 9 Share Posted September 9 (edited) 2012 Q7 TDI Prestige In alldata they list the steps to test the glow plug controller with a volt meter, but they list one terminal (Terminal 10 , relay terminal ST) as 3.44 volts, mine is 12v. They also list terminal 9 (relay terminal D1) as 10.74 volts, but my glow plug controller does not have a terminal 10 on it. Is this correct information or am I OK? Edited September 9 by what2be Quote Link to comment Share on other sites More sharing options...
Bigdave1230 Posted September 9 Share Posted September 9 It depends what engine you have. I think a 3.0 has 10 terminals and a 4.2 has 8 from memory and can be different on engine codes. What symptoms does the car have for you to make you think it’s faulty? Single glow plugs can fail and the holders can become brittle and crack making a poor connection but that’s the only common thing really with them. Quote Link to comment Share on other sites More sharing options...
what2be Posted September 9 Author Share Posted September 9 (edited) It has the 3.0 and I believe it had 9 terminals it was just missing one. It keeps coming up with this: Basic OBD2: P0683 (Permanent) (Pending) (Confirmed) - Glow Plug Control Module to PCM Communication Circuit Engine: 14625 - Glow Plug Control Module 1 to PCM Communication Circuit I checked three of the glow plugs cylinders 4,5,6 and they all tested fine but the boots were so brittle they broke off and on the number five glow plug ( the pressurized one) it came apart and I tried putting it back together but now the car won't start the glow plug icon just flashes so now I need to go buy another pressure glow plug ($170) . I think I'm going to replace the harness for the number 2 and 5 glow plugs as well, its only $85 but it doesn't look like a very fun job to put in. I've got an ABS pressure error as well, from what I've researched sounds like the ABS pumps bad but if that voltage on the glow plug controller is really supposed to be 3.4 v and not 12 v then obviously the ECU has problems Edited September 9 by what2be Quote Link to comment Share on other sites More sharing options...
Bigdave1230 Posted September 9 Share Posted September 9 Sorry I’m a bit unfamiliar with the obd code reader as I use vcds so not sure if it just reads codes or allows you to do measurement tests or not. But yeah the glow plug boots go very brittle and crack where the holder meets the plug and disintegrates when you pull them off. I had a problem with a previous Q7 where it through up a flashing glow plug light before dieing and not restarting so we changed the glow plug module (among many other things) but remember there were a few different types. Unfortunately this seems like one of those annoying faults that’s hard to diagnose and fix 1 Quote Link to comment Share on other sites More sharing options...
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