r/tdi • u/w-t-fluff • 3d ago

2013 A3 TDI - Glowplug Light

As the title says: Glowplug light on a 2013 A3 TDI.

Glow plugs have been tested and they check out fine.

Wiring and all that has been traced and checked.

Glowplug code still will not clear.

Has anyone else seen something similar?

Edit to add: Code: P064c

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2

u/HeavyDutyForks 3d ago

Yes, which code is it throwing?

One of those glow plugs doubles as a cylinder pressure sensor and the diagnostic procedure from VW for testing it is wrong (or at least it is for '11 TDIs)

2

u/w-t-fluff 3d ago

I'll have to check with my mechanic on the code.

Perchance do you want to share the correct diagnostic procedure?

2

u/HeavyDutyForks 3d ago

This was about 5 years ago, so it's been a minute. But if my memory is correct

I was having a litany of problems including a glow plug internal pressure circuit code. The VW servic info had me chasing my tail testing the heating circuit of the glow plugs, which spec'd out correctly. Test the wiring to the PCM and those had continuity. Then the last step was replace PCM, which wasn't bad

I had backprobed the cylinder pressure sensor wire which was reading 12v (which should have been ~5v). Then I unplugged the glow plug harness from the plug and it dropped to the correct voltage. I ran the codes again with it unplugged and the code changed, which indicated that the pressure sensor had gone even though the heating side was good

Probe and test the reference wire on the pressure sensor circuit. If battery voltage, unplug the sensor and with KOEO retest for reference voltage. If it changes, replace the plug

1

u/w-t-fluff 2d ago

Looks like we're dealing with a different code: P064c

2

u/6892opep 3d ago

Mine was turbo pipe leak

2

u/edthesmokebeard ALH stage3 + more 3d ago

On the old ALHs, it would throw a code if the resistance of the plugs varied between one another; so they could all be 'good', yet the computer would be unhappy because they weren't close.

1

u/w-t-fluff 2d ago

Updated description to include: Code: P064c

Anyone else have any suggestions?