P068C

Cylinder 7 Glow Plug Control Circuit Low

Severity

⚠️ Medium

Can you drive?

Yes, but get it checked soon

Approx. repair cost

$17–278 (est.)

Symptoms

Difficulty starting a diesel engine at low temperatures
Check Engine Light
White smoke on cold start
Unstable engine operation
The glow plug indicator is on

Causes

Control wire short circuit to ground
Broken or damaged wiring
GPCM module malfunction
Faulty glow plug for cylinder 7
Oxidation of control circuit connectors

How to Fix

Read OBD-II codes
Inspect the wiring and connectors of cylinder 7 spark plug and GPCM
Measure the voltage in the spark plug control circuit
Check the spark plug resistance (normal: 0.5–2 Ohm)
Check the circuit for short to ground
If the wiring is working properly, diagnose and replace the GPCM

Related codes

P068D P0677 P066A P0670