P06FB Glow Plug Control Module 2 Memory Checksum Error

P06FB means glow plug control module 2 has found a memory checksum error – the counterpart of P06DF for module 1. The module forms a checksum over its memory at power-up and compares it with the stored value. For module 1, Ford's 2023 Power Stroke checks the RAM checksum at power-up (about 1 s); GM's L5P checks the ROM checksum (4.5 s, two trips) and reports it as P064C. No manufacturer document available to us uses a second glow module – Ford's and GM's V8 diesels drive all eight plugs from one; the code suits systems with one module per cylinder bank. The description follows module 1 (P06DF). The usual remedy is reprogramming or replacing the module. The plugs of module 2 then heat poorly or not at all, typically on one bank.

Likely causes

Symptoms

• Check engine light, possibly glow plug/wait-to-start lamp
• Hard cold start, long cranking in frost
• Rough cold idle and white smoke, often one cylinder bank only
• Usually no symptoms when warm

Repair estimate

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

Related codes

References: law.cornell.edu, fordservicecontent.com, gsi.ext.gm.com.