Error P066B on GMC все модели

Symptoms

• Difficulty starting a diesel engine at low temperatures
• The Check Engine light comes on
• Extended warm-up time before starting
• White smoke from the exhaust pipe during cold start
• Unstable engine operation at idle after starting

Causes

• Short circuit of the control wire to the power line (+12 V)
• Open ground circuit in the glow plug control circuit
• Glow Plug Control Module (GPCM) Malfunction
• Damage to control circuit wiring or connectors
• Internal ECU fault

How to Fix

1. Read error codes with an OBD-II scanner and capture a freeze frame of the data
2. Inspect the wiring and connectors of the cylinder 1 glow plug and GPCM
3. Measure the voltage in the spark plug control circuit (the standard corresponds to the manufacturer's specifications)
4. Check the ground circuit for open circuit with a multimeter
5. Check signal wire for short circuit to power
6. If the wiring is working properly, diagnose and replace the GPCM or ECU

FAQ

Error P066B on other vehicles