What it means
Glow Plug Control Module 1 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 1 manages preheating for the diesel engine's glow plugs. The engine controller detects a checksum error in Module 1's memory, meaning the stored data fails its integrity check; this can prevent reliable cold-start preheating.
Common causes
Most likely first.
- Module memory corrupted
- Module software outdated, reflash may resolve
- 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
- Record freeze-frame data and scan all modules for related voltage or glow plug faults before clearing anything.
- Check battery condition and the power and ground connections serving Glow Plug Control Module 1, since unstable supply voltage can corrupt or disrupt its memory.
- Inspect the module connector and harness for corrosion, loose pins, or damage.
- Use the vehicle's diagnostic information to check whether an approved software update or reflash is available for Module 1.
- If supply, wiring, and software checks do not resolve the checksum fault, test or replace Glow Plug Control Module 1 as directed by the manufacturer.
Common fixes
- Restore a weak battery or repair poor module power and ground connections.
- Repair corroded pins or damaged wiring at Glow Plug Control Module 1.
- Reflash the module with the applicable manufacturer-approved software.
- Replace Glow Plug Control Module 1 if its memory fault persists after power and software checks.
Can I keep driving?
If the engine starts and runs normally, short trips may be possible, but allow for difficult starting in cold weather and avoid relying on the vehicle in conditions where a no-start would be unsafe. Persistent preheating failure can increase smoke during warm-up and make cold starting worse.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.