P069D: Cylinder 10 Glow Plug Control Circuit High

Modern diesel glow systems switch each glow plug through its own power semiconductor (in a glow plug module or the engine module), so current and faults can be measured per plug; a faulty channel is switched off. CARB requires glow plugs to be checked for correct current and voltage drop and, since model year 2010, a single plug outside specification to be detected and named. P069D means the circuit to the cylinder 10 glow plug is shorted to battery voltage, so the driver cannot switch it off. GM's engine-module drivers detect an impedance to the supply below 0.5 Ω (0.14 Ω for low-resistance plugs) in 10 of 20 samples, lamps after two trips; Ford's 2023 Power Stroke sees 0 A in its measuring path while the plug is commanded on. A permanently powered plug can overheat and burn through. No manufacturer document available to us uses this code for cylinders 9 and above; the description follows cylinders 1–8.

Low severity. Can I keep driving?You can keep driving, although cold starts will be harder. Avoid cranking the starter repeatedly on cold days.

Cylinder 10 is numbered according to the manufacturer: check your engine's manual before working on it.

Symptoms

Check engine and glow plug lamp
Plug permanently powered, possible battery drain
Plug burns through, then an open-circuit code

Most likely causes

Cylinder 10 plug wire touching battery positive (chafing in the harness)
Moisture or corrosion in the module or plug connector
Driver in the glow or engine module shorted (permanently on)
Glow module software (GM bulletins)

What to check, in order

Start with the simplest. You can tick off each step.

Check the fuse and connector
Check the sensor's ground and make sure the signal wire is not receiving voltage from another circuit.
Measure the resistance of each glow plug with the engine cold
Check the power supply during the preheat cycle
Test the module or relay if the glow plugs are good

Good to know

Repair difficulty: medium
It affects emissions.

What each character of P069D means

P: Powertrain: engine and transmission
0: Generic code: same on every make
6: Control modules and outputs
9D: Specific fault in that system

Frequently asked questions

Can I keep driving with code P069D?

You can keep driving, although cold starts will be harder. Avoid cranking the starter repeatedly on cold days.

What causes code P069D?

The most common causes are: cylinder 10 plug wire touching battery positive (chafing in the harness); moisture or corrosion in the module or plug connector; driver in the glow or engine module shorted (permanently on).

Related codes

Sources

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.