P06BD
Cylinder 5 Glow Plug Circuit Range/Performance.
- Generic
- Powertrain
- Generic code
- Low severity
How this code is built
- P
- SystemPowertrain
- 0
- Defined bySAE, the same on every car
- 6
- AreaComputer and output circuits
- BD
- FaultThe specific fault in that area
What it means
P06BD is the generic code for a range or performance fault in the cylinder 5 glow plug circuit. The engine control unit, or a separate glow plug control module on some vehicles, monitors the current or feedback signal from that glow plug and found it outside the expected range or not matching the commanded state. The circuit is not necessarily open or shorted, so the fault may be an ageing plug, a poor connection or a fault in the control side.
Symptoms
- Glow plug or engine management warning light on
- Hard starting or extended cranking on a cold morning
- White smoke and rough running for the first minute after a cold start
- Slightly increased cold-start emissions and diesel knock
- Fault logged with no obvious change in warm running
Possible causes
- Cylinder 5 glow plug worn, with high or abnormal resistance or a partly failed elementlikely
- Corroded, loose or damaged connector or terminal at the cylinder 5 glow pluglikely
- Damaged, chafed or high-resistance wiring between the glow plug and the control unit or modulepossible
- Low battery voltage or poor power or earth supply to the glow plug systempossible
- Fault in the glow plug control module or driver stage for that channelrare
- Outdated or faulty control unit software affecting glow plug diagnostics (model dependent)rare
How to diagnose
- Read all stored and pending codes plus freeze frame data, noting coolant temperature, battery voltage and engine state when the fault set, and check for other glow plug codes on different cylinders.
- Check the battery condition and charging voltage, and the main fuses and relays for the glow plug supply.
- Inspect the cylinder 5 glow plug connector and wiring for corrosion, heat damage, chafing, bent terminals or oil contamination.
- Carry out a voltage drop test on the supply and earth to the cylinder 5 glow plug while it is energised.
- Measure the resistance of the cylinder 5 glow plug when cold and compare it with the other plugs and the manufacturer specification.
- Measure the current draw of each glow plug during a heat cycle, if the equipment allows, and compare cylinder 5 with the others.
- Use the diagnostic scan tool to run the glow plug output test, if the vehicle supports it, and watch the commanded and actual values for cylinder 5.
- Check for available software updates for the engine or glow plug control unit, as the procedure depends on the model and engine.
How to fix
- Replace the cylinder 5 glow plug, and consider replacing the full set if they are old, following the correct torque and removal procedure for the engine.
- Clean or repair the connector and terminals, or replace the connector if it is damaged or corroded.
- Repair or replace damaged wiring between the glow plug and the control unit or module.
- Restore proper battery condition or repair poor power and earth connections to the glow plug system.
- Replace the glow plug control module if testing proves the output stage is faulty.
- Update the control unit software only if the manufacturer lists an outdated calibration as a known cause for this fault.
Can I keep driving?
The car can normally be driven while you arrange a repair, but cold starting may get harder and emissions are higher until it is fixed. Have it checked soon, especially before winter, and avoid repeated long cranking.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.