Fault Family System: Powertrain (P-Codes) 6 SAE Codes

Engine Cooling Fan Control Module

Diagnostic & Technical Explanation

Code P2D87 (Fan 1 Control Module Over Temperature) sets when the electronic fan speed control module for the named fan reports an over-temperature condition, an internal performance fault, or a supply voltage outside its operating range. Because this module drives the fan motor's variable-speed circuitry directly, causes are a degraded thermal path between the module's power devices and its heatsink, a corroded low-voltage connector, or sustained high-load fan operation that outpaces the module's cooling.

These 6 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 6 times.

Codes in this family (6)

Code	Definition	Repair coverage
P2D87	Fan 1 Control Module Over Temperature	3 ranked fixes
P2D88	Fan 1 Control Module Performance	3 ranked fixes
P2D89	Fan 1 Control Module Supply Voltage Circuit	3 ranked fixes
P2D8A	Fan 2 Control Module Over Temperature	3 ranked fixes
P2D8B	Fan 2 Control Module Performance	3 ranked fixes
P2D8C	Fan 2 Control Module Supply Voltage Circuit	3 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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