P06BD: Cylinder 5 Glow Plug Circuit Range/Performance

What does P06BD mean?

The glow module calculates each plug's resistance from voltage and current while glowing. 'Range/performance' means the circuit is electrically intact but the resistance or current lies outside the specified window – typically an aged, high-resistance or wrong plug or contact resistance at the connector. CARB requires a single plug outside specification to be detected from model year 2010. Ford's 2023 6.7 L/3.0 L Power Stroke runs this check during heating after the open and short checks and flags a circuit above 2 Ω after about 3 s. GM does not use this code family. Ram's 6.7 L Cummins (from model year 2025, with glow plugs instead of the grid heater) set these codes falsely; the fix was reprogramming the engine module.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Check engine and glow plug lamp
• Harder cold start in frost
• Rough running and white smoke after a cold start
• Often no symptom when warm

Common causes

• High Glow plug cylinder 5 aged or high-resistance
• Medium Contact resistance at plug connector or terminal nut
• Medium Wrong plug type or a plug with a manufacturing fault
• Low Engine or glow module software (Ram 6.7 L from 2025)

Likelihood is a general estimate across vehicles; your make and model may differ.