P06FB: Glow Plug Control Module 2 Memory Checksum Error

What it means

Glow Plug Control Module 2 Memory Checksum Error: the control module has detected this fault condition. This affects diesel cold-start preheating.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

Glow plug control module 2 stores operating data or software that it checks for integrity. P06FB sets when the module's memory checksum does not match the expected value, which can follow corrupted memory, software issues, or unstable supply voltage.

Common causes

Most likely first.

1. Module memory corrupted
2. Module software outdated, reflash may resolve
3. Supply voltage outside specification

Symptoms

• Glow plug warning light on (often orange coil symbol)
• Hard cold start or no start in cold weather
• White smoke from exhaust during warm-up

How to diagnose it

1. Save freeze-frame data and scan for other module 2, communication, or voltage codes that may explain the checksum failure.
2. Inspect module 2 power, ground, and connectors for corrosion or intermittent contact that could disrupt stored data.
3. Check battery and charging-system operation and compare supply stability with the manufacturer's specification.
4. Confirm whether an applicable software update or module reprogramming procedure is available for the vehicle before replacing hardware.
5. If supply and software checks do not resolve the fault, test module 2 according to the manufacturer's procedure and replace it if its memory remains faulty.

Common fixes

• Repair poor module 2 power or ground connections and clear the code.
• Correct battery or charging faults that cause unstable module supply.
• Update or reprogram module 2 if the manufacturer provides a relevant software correction.
• Replace glow plug control module 2 if its memory checksum fault returns after supply and software issues are addressed.

Can I keep driving?

The vehicle may drive normally, but module 2 may not manage preheating reliably, leading to hard cold starts or white smoke during warm-up. Avoid repeated prolonged cranking and address the fault before cold conditions.