Internal memory corruption or failure inside the glow plug control module 2; Low or unstable battery voltage during module power-up, corrupting the checksum; Poor ground or corroded power feed to the glow plug control module 2; Water intrusion or connector corrosion at the module causing intermittent communication; A failed software flash or interrupted programming event on the module; Wiring harness damage between the engine control module and glow plug control module 2

DTC codes / P06xx · Computer and output circuits / P06FB

P06FBGlow Plug Control Module 2 Memory Checksum Error

Q: What does code P06FB mean?

Glow Plug Control Module 2 Memory Checksum Error. P06FB means the glow plug control module number two has detected a checksum error in its own memory, so the module cannot trust the calibration or strategy data it relies on to operate the glow plugs. The engine control module sets this code after the glow plug module reports that its internal memory verification has failed.

P06FB means the glow plug control module number two has detected a checksum error in its own memory, so the module cannot trust the calibration or strategy data it relies on to operate the glow plugs. The engine control module sets this code after the glow plug module reports that its internal memory verification has failed.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

AreaComputer and output circuits

Symptoms you may notice

Illuminated check engine light or glow plug warning lamp, often with no other symptoms
Hard cold starting or extended cranking before the engine fires
Rough idle and white smoke from the exhaust immediately after a cold start
Glow plug system disabled, causing poor cold-weather driveability
In some vehicles, a reduced-power or limp-home message on the dashboard

Common causes, most likely first

Internal memory corruption or failure inside the glow plug control module 2
Low or unstable battery voltage during module power-up, corrupting the checksum
Poor ground or corroded power feed to the glow plug control module 2
Water intrusion or connector corrosion at the module causing intermittent communication
A failed software flash or interrupted programming event on the module
Wiring harness damage between the engine control module and glow plug control module 2

How to diagnose and fix it

Scan all modules and record freeze-frame data and any companion codes before clearing anything
Test battery condition and charging voltage, then check the module's power and ground circuits for voltage drop
Inspect the glow plug control module 2 connector and harness for corrosion, water intrusion, and chafing
Verify communication between the engine control module and glow plug control module 2 with a scan tool
Check for and apply any available module software update or recalibration from the manufacturer
If voltage, grounds, and software are correct, replace the glow plug control module 2 and clear the code
After repair, run a cold-start glow plug self-test and confirm the code does not return over several drive cycles

Why a checksum code is rarely the glow plugs

A checksum error points to the module's internal memory integrity, so replacing glow plugs themselves will not fix this code and is a common wasted repair.
A weak battery that still starts the engine can drop voltage far enough during cranking to corrupt the module's memory check, so always load-test the battery first.
Corroded grounds at the module are a frequent hidden cause because they create voltage spikes that the module interprets as memory faults.
This code can be stored intermittently after a failed or interrupted reprogramming event, and a successful reflash may clear it without parts replacement.
On some platforms the glow plug control module 2 is a slave module, and a communication fault elsewhere in the network can cause a false checksum report.

Can I keep driving with P06FB?

The vehicle will usually start and run, but cold starting and cold-weather driveability are compromised and the glow plug system may be disabled. Avoid repeated cold starts and long cranking until the fault is diagnosed, and do not replace glow plugs before checking module power, grounds, and software.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.