Cylinder 12 Glow Plug Circuit Range/Performance
This code means the PCM/ECM has detected a circuit performance problem affecting cylinder 12 glow plug. Because combustion on the affected cylinder or circuit is disrupted, drivers may notice rough running, misfires, hard starts, or reduced power.
What You Might Notice
- Check Engine Light illuminated
- Hard cold starting
- Long cranking in cold weather
- Rough idle after start-up
- White smoke on cold start
Most Common Causes
- 1
Failed glow plug
- 2
Faulty glow plug control module or relay
- 3
Open or high-resistance glow plug wiring
- 4
Low battery voltage
- 5
PCM/ECM fault
How to Diagnose It
- 1
Check Failed glow plug — Inspect for signs of failure and test before replacing.
- 2
Check Faulty glow plug control module or relay — Inspect for signs of failure and test before replacing.
- 3
Check Open or high-resistance glow plug wiring — Inspect for signs of failure and test before replacing.
- 4
Check Low battery voltage — Inspect for signs of failure and test before replacing.
- 5
Check PCM/ECM fault — Inspect for signs of failure and test before replacing.
How to Fix It
- 1
Test the affected coil, glow plug, or ignition-related component
- 2
Inspect spark plugs and basic engine condition
- 3
Repair damaged wiring, grounds, or connector pins
- 4
Replace the failed ignition-related part
- 5
Clear the code and confirm the symptom is gone
Need a deeper diagnosis?
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