P068E

Cylinder 8 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 diesel V8 at low temperatures
Check Engine Light
White smoke on cold start
Unstable engine operation after starting
The glow plug indicator is on

Causes

Control wire short circuit to ground
Broken or damaged wiring
GPCM module malfunction
Faulty glow plug cylinder 8
Oxidation of connectors

How to Fix

Read OBD-II codes
Inspect the wiring and connectors of the cylinder 8 spark plug and GPCM
Measure the voltage in the control circuit
Check the spark plug resistance (normal: 0.5–2 Ohm)
Check the circuit for short to ground
If the circuit is working properly, diagnose and replace the GPCM

Related codes

P068F P0678 P068C P0670