P06E1

Code

Generic P — Powertrain

Cylinder 11 Glow Plug Control Circuit High

Brand: Generic

Type: P — Powertrain

Views: UK: 24 EN: 31 RU: 24

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Page language: EN

Causes

Short to battery voltage (wiring harness shorted to B+) on cylinder 11 circuit
Failed/shorted glow plug (very low internal resistance)
Stuck or failed glow plug relay or glow control module (stuck closed or internal fault)
PCM / driver transistor fault or internal monitoring circuit failure
Corroded/damaged connector pins or poor terminal contact causing abnormal readings
Aftermarket modification or incorrect replacement part installed

Symptoms

Engine may be hard to start when cold
Glow plug indicator lamp may stay on or flash
Illuminated MIL / Check Engine Light
Possible rough idle or misfire on cylinder 11 under cold start conditions
Other glow plug related faults or multiple cylinder codes if a module is failing

What to check

Read and record freeze frame and live data with a scan tool (glow command status, voltage/current if available)
Visually inspect wiring and connector at cylinder 11 glow plug and at the glow control module/relay for damage or corrosion
Check for related codes for other cylinders or glow control module
Measure supply voltage to glow plug harness with key ON and during glow cycle
Measure resistance of the suspect glow plug (while disconnected from harness)
Back-probe connector to observe voltage when PCM commands glow on/off

Signal parameters

Supply voltage to glow plug when commanded: typically close to battery voltage (approx. 11–14.5 V) — may be PWM-controlled on some systems
Expected current per glow plug: system-dependent; excessive instantaneous current suggests shorted plug or short to B+
Typical cold glow plug resistance: often low (sub-ohm to a few ohms) — consult OEM spec for exact value
PCM driver expected state: open/grounded or PWM drive to modulate current — monitor command vs actual voltage

Diagnostic algorithm

Retrieve code(s) and freeze-frame data. Note battery voltage and engine conditions when the fault set.
Inspect visually: wiring, harness, connectors at cylinder 11 and at the glow control module/relay for damage, melting, corrosion or rodent chew.
With ignition ON (engine off), use a DVOM to measure voltage at the glow plug connector while commanding glow ON via scan tool. Confirm voltage behavior matches command (ON = B+ or expected PWM, OFF = no drive).
Disconnect the cylinder 11 glow plug connector and re-check voltage at the harness. If high voltage disappears, suspect harness/connector or glow plug. If high remains, suspect module/PCM.
Measure the resistance of the removed glow plug. Compare to spec or to another cylinder. A very low resistance indicates a shorted glow plug; a very high/open indicates open circuit (less common for 'high' code but useful to isolate faults).
If available, monitor current draw for the circuit during activation. Excessive current indicates a shorted glow plug or short to B+. No current while commanded may indicate open or driver fault.
Swap the suspect glow plug with a known-good plug or swap connectors between cylinder 11 and another cylinder (if identical) to see if the DTC follows the plug or stays with the cylinder/harness.
If swap isolates the plug as faulty, replace the glow plug. If the fault stays with wiring, perform continuity and short-to-power tests on the harness; repair or replace damaged wiring/connectors.
If wiring and plug check good, test or replace glow control relay/module. If module replacement does not clear issue, consider PCM driver fault and consult manufacturer procedures before replacing PCM.
After repairs, clear codes and perform several glow cycles or drive cycle to verify the DTC does not return.