OBD-II Code
P0680
Severity
Not yet reviewed
Nobody on our side has assessed this code yet, so we are not going to guess at how serious it is.
Can you drive it
We cannot say
Treat it as unknown until a shop reads it with live data. If the check-engine light is FLASHING, stop driving as soon as it is safe to — that means an active misfire, whatever the code.
Indicative cost (USD)
$400–$4,500
From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
$400 (single plug on a 6.5 industrial) to $4,500 (Touareg V10 single plug with required front-clip service access).
P0680 means the ECU detected a glow plug circuit fault on cylinder 9 — open, short, or out-of-spec resistance from the GPCM.
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then follow the diagnostic notes further down this page, in the order they are written.
They are written in the order a shop works this code, cheapest checks first. Where they name a component, inspect its wiring and connector before replacing it.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Check engine light
Read the full diagnostic procedureP0680 means the ECU detected a glow plug circuit fault on cylinder 9 — open, short, or out-of-spec resistance from the GPCM.
P0680 means the ECU detected a glow plug circuit fault on cylinder 9 — open, short, or out-of-spec resistance from the GPCM.
The cheapest-first diagnostic ladder
- Ohm the cyl 9 plug at its terminal — healthy 0.4-2.0 ohms cold (most diesels 0.6-1.2 ohms), 0 shorted, infinite open, 4+ weak.
- Verify GPCM PWM command at 0-100% duty cycle with glow-on time 5-30 sec scaled to coolant temp.
- Amp probe on the cyl 9 feed should show 7-20A initial draw dropping to 5-15A as the plug heats; flat 0A with command ON = open, sustained 20A+ = short. Cylinder 9 only exists on 10-cylinder or 12-cylinder diesels, which in light-duty/medium-duty shop work means a V10 — the VW V10 Touareg TDI is the most common 10-cylinder diesel a North American shop will see, with the GM Detroit Diesel 6.5L V8 mapping cyl 9 to special GPCM channels in some industrial/marine configurations. Test resistance INDIVIDUALLY at the glow plug terminal — pulling a shorted plug measures 0 ohms; an open plug measures infinite; a marginally weak plug measures 4+ ohms cold and is the most common cold-start hard-start root cause. Replace as a set on diesel engines — mixed-age plugs cause progressive failure.
Vehicle-specific patterns2004-2010 VW Touareg V10 TDI (5.0L BWF/BLE) is the primary P0680 platform in North American shops — cylinder 9 is on the rear of the right bank and i…
- 2004-2010VW Touareg V10 TDI (5.0L BWF/BLE) is the primary P0680 platform in North American shops — cylinder 9 is on the rear of the right bank and is one of the hardest plugs to reach on a chassis that already requires removing the front clip (the famous Touareg V10 service position) for any major engine work; expect 4-6 hr labor on a single plug. The V10 TDI's glow plug system uses a Beru GPCM that's known to fail in cold climates and throws P0680 + multiple other per-cyl codes simultaneously.
- 2001-2007Audi A8 / Q7 V12 TDI in European-market shops throws P0680 from the same Beru/Bosch GPCM family.
- 1994-2002GM Detroit Diesel 6.5L V8 in commercial/military Hummer applications maps cyl 9 to an extended GPCM channel in some configurations — verify the FSM matches the wiring before assuming a hardware fault.
Estimated repair$400 (single plug on a 6.5 industrial) to $4,500 (Touareg V10 single plug with required front-clip service access).
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