2012 Jetta MK6 - 6-speed manual - Glow Plug Troubleshooting

[Benedict]

Good afternoon, am helping my sister with her Jetta. It is a 2012 CJAA engine with a 6-speed manual gearbox.

I have a CRUA dsg wagon, so learning this will help me in the future.

I have read through Wingnut's glowplugs 101 thread, am hoping anyone can help with some specific questions,

I have some experience doing maintenance on cars, and I have the vcds Ross-tech software. I don't have much experience trouble shooting, and I don't know much about electrical,

Before beginning there were pressure sensor fault codes for all four cylinders, a control relay fault code, and open circuit on one of the glow plugs.

For better or worse, I decided to go with aftermarket glow plugs (SMP GP119). The continuity on the new plugs looked good at 0.6ohms (my meter wires have 0.2ohm resistance).

I checked the wiring harness for continuity from the relay terminals to the plug boots, they are good.

All fuses in the fuse box look good when tested.

I checked for voltage going from the wire harness to the relay terminals, and I checked the power terminals (30 and 87) with the light tester, they looked good although I don't know what the correct voltage should be for pins ST and D1 (ST shows 3.45v, D1 shows 10.6v). The ground terminal looked good with the ohms and light tester.

The original relay/controller is oem part number "03L 907 282", the oem superseded part is "03L 907 282 B". The original relay looks to be discontinued.

I wanted to check if the pressure sensor code was due to the aftermarket glow plugs. I put two of the original good plugs back in (they are oem), and the car continued to throw pressure sensor fault codes for all four cylinders.

The new relay arrived yesterday. Installed and faults cleared, and I have five fresh fault codes,

005072 - Cylinder 1 Internal Pressure Sensor
P13D0 - 003 - Implausible Signal - MIL ON

005078 - Cylinder 3 Internal Pressure Sensor
P13D6 - 003 - Implausible Signal - MIL ON

005081 - Cylinder 4 Internal Pressure Sensor
P13D9 - 003 - Implausible Signal - MIL ON

005075 - Cylinder 2 Internal Pressure Sensor
P13D3 - 003 - Implausible Signal - MIL ON

005075 - Cylinder 2 Internal Pressure Sensor
P13D3 - 000 - Implausible Signal - MIL ON

My CRUA engine uses the same original relay. Earlier today I took it from my car (since it is known as good), cleared my sister's fault codes and she went to run errands. I will hear back from her later today if the engine light comes back on. I won't be able to drive my car with the new relay until this evening to see what happens.

My Questions:

First, Wingnut mentioned to check power to the glow plugs by unhooking the coolant temp sensor. Does anyone know where it is located on the CJAA with a manual gearbox?

Second, can the pressure sensor wire for each cylinder be checked? If so which part of the glow plug boot do you check, and what terminal at the relay (or somewhere else)?

Third, one of the youtube videos I came across mentioned that for the newer relay/controller a software update is needed. Can anyone confirm or deny this?

Lastly, if my sister's fault codes persist, does anyone else have suggestions on things to check next?

 

[turbodieseldyke]

Those errors are not on the high-amperage lines from the relay (the "glow" function), they are on the thinner signal wires (pressure sensor function) from the ecu. Many of the wiring problems are not at the glow plug connectors, but farther back in the harness, behind the oil filter area, where the harness is subjected to rubbing and heat.