P06C3

Code

Generic P — Powertrain

Cylinder 11 Glow Plug Circuit Range/Performance

Brand: Generic

Type: P — Powertrain

Views: UK: 23 EN: 30 RU: 29

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Page language: EN

Causes

Open or short in glow plug wiring for cylinder 11
Failed glow plug (high resistance or open)
Poor connector contact or corrosion at glow plug connector
Blown fuse or faulty glow plug relay/module
Faulty engine control module (ECM)/glow driver output
Intermittent wiring damage (chafing, pinched harness)

Symptoms

Illuminated MIL/check engine light with P06C3 stored
Longer-than-normal cold start cranking or rough cold start
Engine misfire or rough idle during cold conditions
Reduced cold start drivability, increased white smoke on start (diesels)
Possible hard start when ambient temperature is low

What to check

Retrieve DTCs and freeze frame with a scan tool. Note any related codes (other cylinders, powertrain, battery).
Visually inspect glow plug harness, connectors and grounds for damage, corrosion or loose pins at cylinder 11.
Check relevant fuses and glow relay/module for proper function.
Measure battery voltage at glow plug connector with glow command active using a scan tool.
Measure resistance of the glow plug (cold) at the connector with ignition OFF.
Perform a current draw test on the glow plug circuit if safe access and proper equipment available.

Signal parameters

Expected battery voltage at glow plug connector when commanded: approximately battery voltage (11–14.5 V) or manufacturer-specified value
Typical cold glow plug resistance (varies by type): roughly 0.3–2.5 ohms; consult OEM spec for exact value
Typical current draw per glow plug: commonly several amps (often 4–20 A depending on design); compare to OEM spec
ECM/glow driver output may be PWM or switched ground; verify presence of command signal when glow is active
Open or very high resistance indicates open circuit or failed element; zero or very low resistance short indicates short to ground

Diagnostic algorithm

Read and record all DTCs and freeze-frame data. Attempt to reproduce the condition if safe (cold start or commanded glow cycle).
Visually inspect harness, connectors, pins, and ground points for cylinder 11. Repair any obvious damage or corrosion.
Verify fuses and glow relay/module operation. Replace relay/fuse if defective, then re-scan.
With ignition OFF, disconnect the cylinder 11 glow plug connector and measure the resistance of the glow plug. Compare to OEM spec. If out of range, replace the glow plug.
With a fused meter or clamp ammeter and appropriate safety measures, command the glow plug ON using a scan tool and measure voltage and current at the connector. Confirm the ECM is commanding and the plug draws expected current.
If voltage is present but current is low or zero, suspect open element or high-resistance connection. If no voltage, trace back for open circuit, bad relay, blown fuse, or bad driver output.
Inspect and test continuity of wiring and any in-line splices between ECM/relay and the glow plug. Repair any breaks or high-resistance joints.
If wiring and glow plug test good but driver output is abnormal, test the glow relay/module and the ECM driver circuit. Replace the module or consult OEM procedures before replacing ECM.
After repair, clear codes and perform multiple key cycles and a cold start test to confirm proper function and that the code does not return.

Likely causes

Failed glow plug in cylinder 11 (most common)
Corroded/loose connector or poor ground near cylinder 11
Open circuit or high-resistance splice/connector in the harness to cylinder 11
Defective glow plug relay/module or blown fuse affecting that bank
Driver transistor in ECM partially failed causing incorrect current or PWM

Fault status

⚠️ Status

Cylinder 11 glow plug circuit range/performance out of expected parameters. System detected abnormal voltage/current/resistance or response when commanding cylinder 11 heater.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours