P06FB

What it means

P06FB is a generic code meaning the second glow plug control module has failed its internal memory checksum check. The module calculates a checksum of its stored software and calibration data at start-up and compares it with the expected value. A mismatch means the data may be corrupt, so the fault is logged and the module's output may be restricted.

Symptoms

• Glow plug or engine management warning light on
• Hard starting or extended cranking, especially when cold
• White smoke or rough running on a cold start
• Glow plugs not operating or operating erratically
• Other glow plug circuit or communication codes stored alongside

Possible causes

• Internal fault in glow plug control module 2 (corrupted memory)likely
• Low or unstable supply voltage to the module from a weak battery or poor chargingpossible
• Poor power or earth connections to the module, including corrosion or loose terminalspossible
• Water ingress or heat damage to the module or its connectorpossible
• Interrupted software update or outdated or faulty module calibrationrare
• Wiring damage or a short on the module's output side causing a module failurerare

How to diagnose

1. Read all stored codes and freeze frame data, noting battery voltage, coolant temperature and engine state when the code set
2. Check for related codes such as glow plug circuit, communication or supply voltage faults, and deal with those first
3. Test battery condition and charging voltage, as low voltage can corrupt memory during start-up
4. Inspect the module, its connector and wiring for corrosion, water, heat damage, chafing or loose pins
5. Check the module's power feeds and earth connections for voltage drop under load
6. Clear the code, then cycle the ignition and retest to see if it returns immediately, which points to a hard fault
7. Check for available software updates or service bulletins for the specific model and engine, as module location and numbering vary
8. Confirm which glow plug module is number 2 for the vehicle using the manufacturer's information, as this depends on the engine layout

How to fix

• Repair or replace the battery or charging system if voltage is low or unstable
• Clean, tighten or repair corroded power and earth connections and damaged wiring
• Dry out and repair any water ingress source, and replace the connector if damaged
• Update or reprogram the module's software if an outdated or faulty calibration is confirmed as the cause
• Replace glow plug control module 2 and code it to the vehicle if it has an internal memory fault

Can I keep driving?

Nearby codes

• P06FAGenericGlow Plug Control Module 2 Performance
• P06FCGenericGlow Plug Control Module 2 to PCM Communication Circuit