Cylinder 4 Glow Plug Control Circuit Low
What it means
P067A is a diesel code meaning the control circuit for the cylinder-4 glow plug is reading low — typically a short to ground or an open in that plug's circuit. Glow plugs pre-heat each cylinder for cold starting, so a faulty one on cylinder 4 makes cold starts harder and smokier. It points at that specific glow plug or its wiring rather than the whole engine.
Can I keep driving? The engine usually still runs, but the cylinder-4 glow plug is not being controlled properly, so cold starts can be harder and smokier until it is repaired.
Real-world scan data
Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.
Common symptoms
What you'll notice
- Check-engine light on (often with a glow-plug warning light)
- Harder starting when cold
- Rough running or a slight miss until the engine warms up
- White exhaust smoke on a cold start
Common causes
Most likely first
- Faulty cylinder-4 glow plug (shorted or low resistance)Likely
- Glow-plug control wire shorted to ground or the harness openCommon
- Corroded or loose connector at the cylinder-4 glow plugCommon
- Faulty glow plug control moduleLess often
How to diagnose & fix
Work through it in order
- Scan and read freeze-frame data to confirm the fault is on the cylinder-4 glow-plug control circuit.
- Locate the cylinder-4 glow plug and inspect its connector and wiring for a short to ground, chafing, or an open.
- Measure the glow plug's resistance and compare it to the others; replace it if it reads shorted or out of spec.
- If the plug and wiring are good, test the glow plug control module output for that cylinder and replace the module if it is at fault.
FAQ
Quick answers
Is it safe to drive with P067A?+
Can I just clear P067A?+
Related codes
Read & clear P067A yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.