Fault-Code Library · Diesel preheating
P0671: Cylinder 1 glow-plug circuit
The glow-plug circuit for cylinder 1 has an electrical or current-consumption fault.
Common symptoms
- •Hard cold starting
- •Cold-start misfire
- •White smoke
- •Glow-plug warning
Likely causes
- •Failed glow plug
- •Connector or harness fault
- •Glow module channel failure
- •High circuit resistance
First checks
- •Compare resistance across all glow plugs
- •Inspect the cylinder 1 connector
- •Confirm module output before replacing parts
Important
Identify cylinder numbering from manufacturer information before testing or removal.
A fault code identifies a detected condition, not a failed part. Confirm manufacturer-specific subcodes and live data.
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