P069D: Cylinder 10 Glow Plug Control Circuit High

What it means

The control line for the glow plug on cylinder 10 is open or shorted to supply - the plug cannot be heated.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

The glow plug on cylinder 10 heats the combustion chamber to help a diesel engine start when cold. P069D sets when the module detects a high or open condition in cylinder 10's glow plug control circuit, which can leave that plug unable to heat.

Common causes

Most likely first.

1. Open in plug or wiring
2. Connector pins corroded - high contact resistance
3. Supply wire pinched against B+ source

Symptoms

• Glow plug warning light on (often orange coil symbol)
• Hard cold start or no start in cold weather
• White smoke from exhaust during warm-up

How to diagnose it

1. Record freeze-frame data and scan for other glow plug circuit codes to confirm whether cylinder 10 is the only affected cylinder.
2. With the engine cool and ignition off, inspect the cylinder 10 glow plug connector and wire for disconnection, corrosion, broken insulation, or a backed-out pin.
3. Compare cylinder 10 glow plug command or current data with other cylinders during a cold start, if available.
4. Check continuity through the cylinder 10 glow plug and control wire using the vehicle wiring information to locate an open.
5. If the plug and wiring pass inspection, test circuit output and connections against the manufacturer's specification.

Common fixes

• Reconnect or repair an open in the cylinder 10 glow plug wire.
• Clean corrosion and repair a loose or damaged connector terminal.
• Replace the cylinder 10 glow plug if it tests open.
• Clear the code and confirm the circuit operates during a cold start.

Can I keep driving?

The vehicle may start and drive in warm conditions, but cold starting can be difficult and warm-up may produce white smoke. Avoid repeated extended cranking to reduce battery and starter strain.