Fault Family System: Powertrain (P-Codes) 29 SAE Codes

Fuel Heater Control Circuit

Diagnostic & Technical Explanation

P23C7 (Fuel Heater Control Module Power Control Circuit/Open) covers the electric fuel-warming heaters that some diesels use on the fuel rail or at individual injector positions to prevent fuel waxing and injector icing in cold weather. The fault can point to the control module's own driver circuit, the feedback signal confirming the heater actually drew current, or an open or shorted heating element at a specific cylinder position, and each of those points to a different repair.

These 29 diagnostic trouble codes share one detection mechanism and one repair path, which is why MechanicDB groups them into a single authored fault family rather than repeating the same explanation 29 times.

Codes in this family (29)

Code	Definition	Repair coverage
P23C7	Fuel Heater Control Module Power Control Circuit/Open	4 ranked fixes
P23C8	Fuel Heater Control Module Power Control Circuit Low	4 ranked fixes
P23C9	Fuel Heater Control Module Power Control Circuit High	4 ranked fixes
P23CA	Fuel Rail Heater Control Circuit/Open	4 ranked fixes
P23CB	Fuel Rail Heater Control Circuit Low	4 ranked fixes
P23CC	Fuel Rail Heater Control Circuit High	4 ranked fixes
P23CD	Fuel Heater Control Module Feedback Signal/Open	4 ranked fixes
P23CE	Fuel Heater Control Module Feedback Signal Performance	4 ranked fixes
P23CF	Fuel Heater Control Module Feedback Signal Circuit Low	4 ranked fixes
P23D0	Fuel Heater Control Module Feedback Signal Circuit High	4 ranked fixes
P23D1	Cylinder 1 Fuel Heater Control Circuit/Open	4 ranked fixes
P23D2	Cylinder 1 Fuel Heater Control Circuit High	4 ranked fixes
P23D3	Cylinder 1 Fuel Heater Control Circuit Low	4 ranked fixes
P23D4	Cylinder 1 Fuel Heater Performance	4 ranked fixes
P23D5	Cylinder 2 Fuel Heater Control Circuit/Open	4 ranked fixes
P23D6	Cylinder 2 Fuel Heater Control Circuit High	4 ranked fixes
P23D7	Cylinder 2 Fuel Heater Control Circuit Low	4 ranked fixes
P23D8	Cylinder 2 Fuel Heater Performance	4 ranked fixes
P23D9	Cylinder 3 Fuel Heater Control Circuit/Open	4 ranked fixes
P23DA	Cylinder 3 Fuel Heater Control Circuit High	4 ranked fixes
P23DB	Cylinder 3 Fuel Heater Control Circuit Low	4 ranked fixes
P23DC	Cylinder 3 Fuel Heater Performance	4 ranked fixes
P23DD	Cylinder 4 Fuel Heater Control Circuit/Open	4 ranked fixes
P23DE	Cylinder 4 Fuel Heater Control Circuit High	4 ranked fixes
P23DF	Cylinder 4 Fuel Heater Control Circuit Low	4 ranked fixes
P23E0	Cylinder 4 Fuel Heater Performance	4 ranked fixes
P2687	Fuel Supply Heater Control Circuit/Open	4 ranked fixes
P2688	Fuel Supply Heater Control Circuit Low	4 ranked fixes
P2689	Fuel Supply Heater Control Circuit High	4 ranked fixes

What this page does not show

This page publishes the fault mechanism and the code index. The licensed dataset adds, for every one of the 15,886 codes, the full authored repair set (56,729 procedures in total) with the fields deliberately withheld here:

Procedures 2..n after the first-listed procedure
Aftermarket parts cost ranges in USD (est_parts_cost_min/max_usd)
Professional labor-hour estimates (est_labor_hours)
Step-by-step diagnostic and repair instructions
Replacement-part mappings and catalog lookups
6,637 manufacturer-specific OEM codes across 32 makes ($149 tier)

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