I messed up

showfire

Member
Joined
Feb 20, 2018
Location
Colorado
TDI
2003 Jetta TDI
I messed up (solved)

Yesterday I made a huge mistake and connected jumper cables up to my 2003 VW Jetta TDI backwards. The car still starts and runs thankfully but now I have two error codes that have shown up.
P0672 cylinder 2 glow plug circuit/open
P0228 throttle/pedal position sensor/switch “c” circuit high
Any suggestions on where to start with repairing my stupid mistake?
I was going to start with checking the glow plug in cylinder 2.
 
Last edited:

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
Weird that it JUST did that.

The accelerator pedal assembly is one unit, with both sensors inside it. Couple fasteners hold it to the firewall.

Manual and automatic cars use different pedal assemblies, but the two different manufacturers VAG used are interchangeable.
 

showfire

Member
Joined
Feb 20, 2018
Location
Colorado
TDI
2003 Jetta TDI
Thank you, that is good to know. My car is a manual, this definitely helps to know the sensors are the same.
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
Replace the GP Relay and fuse and check the GP's to see if there still good, replace the TPS on the peddle assembly and any relays or fuses. thats cheep and report back if not fixed. Its odd that this happened as all modern cars have a main fuse on the main input of the fuse box, usualy 100-150 amps, that would have blown first but im shocked it did damage, not the worst thing, just a few electrical parts.
 

showfire

Member
Joined
Feb 20, 2018
Location
Colorado
TDI
2003 Jetta TDI
Thank you for the suggestions, I am working through them. Most of this work will be done on weekends. There weren't any blown fuses, but one in the black box on top of the batter with the largest cable looks iffy so I plan to replace it.

I will keep everyone posted on my progress. I will keep looking at this thread so if you think of anything else I should check or replace let me know.
 

showfire

Member
Joined
Feb 20, 2018
Location
Colorado
TDI
2003 Jetta TDI
My progress so far has been to replace the battery, I found the 150A fuse on the over battery fuse box had blown. I replaced that after hunting for a couple hours for one.

I checked all of the glow plugs, but they seem to have too low of a resistance based on the tutorial from Wingnut. I am measuring everything around 0.1 ohms, did I do something incorrect or are they bad?

The relay is delivering 11.75-12.10 V to the connectors for the glow plugs when the power is turned on for the car.

I cleared the code and started the engine, it ran smooth but a little on the rich side. I could smell diesel that had not been burned. The code did not come back, instead I am getting:

P0684 - glow plug control module to PCM communication circuit range/performance

Any suggestions about this one? I am thinking there may be a bad connection near the relay but I am not sure. Where is the relay located?

I haven't had a chance to deal with the throttle sensor yet, but I will be removing the throttle this evening and probably getting a new part from a salvage yard on Monday. This error is still the same and present.
 

JB05

Top Post Dawg
Joined
Oct 20, 2005
Location
Il.USA
TDI
Golf,2005,anthracite blue
On my BEW the smart relay is located at the base of the windshield, under the plastic cowl cover on the driver's side. I can see it through the vents. Don't know if your '03 has the same location, but it's worth a quick glance.
 

showfire

Member
Joined
Feb 20, 2018
Location
Colorado
TDI
2003 Jetta TDI
I don’t see anything back there, just cables and the firewall. But, I may be looking in the wrong spot. In front of the plastic there there is a box above the master brake cylinder with 2 relays but they don’t look like the images I found of the glow plug relay. I reseated both for good measure though.
 

jettawreck

Top Post Dawg
Joined
Aug 2, 2004
Location
Northern Minnesota-55744
TDI
2001 Jetta and 2003 Jetta
The GP relay on the '03 is under the raintray cowl at the base of the windshield where the ECU, wiper motor and hardware lives. Rectangular black box aprox 2x2x4" or a bit smaller as I recall.
 

showfire

Member
Joined
Feb 20, 2018
Location
Colorado
TDI
2003 Jetta TDI
I have an OBDII reader that connects to my laptop via bluetooth, not sure if this is the same as a VAG-COM. Anyways, I found the box you are talking about; it took a trip to the salvage yard to see where the box was.

My current situation is much better. I replaced the suspect fuse and the battery. I then cleared the codes but they both came back. I looked some up some information about replacing the Throttle position sensor and saw that part of the install was to push the throttle to the floor for 5 seconds in the ACC position. Since I would have to order the TPS anyways I decided to try this installation step after clearing the codes. This seems to have resolved both issues.

After the last clearing of the trouble codes and this "reset" of the TPS the problems seem to be resolved. I will keep you posted over the next week in case the codes come back.
 

showfire

Member
Joined
Feb 20, 2018
Location
Colorado
TDI
2003 Jetta TDI
After driving to and from work for a week, there are no errors coming back and it is performing great. Thank you for the suggestions and the help.
 
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