Fault Family System: Powertrain (P-Codes) 8 SAE Codes

Hybrid Electronics Aux Cooling

Diagnostic & Technical Explanation

Code P0A7C sets when the auxiliary power-electronics cooling loop cannot maintain the commanded temperature or performance for the secondary cooling loop that protects the inverters and power electronics. The most common physical causes are a low coolant level or trapped air in the loop, a clogged or damaged auxiliary radiator, and a failing coolant pump or fan for that loop.

These 8 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 8 times.

Codes in this family (8)

Code	Definition	Repair coverage
P0A7C	Motor Electronics Over Temperature	3 ranked fixes
P0A93	Inverter A Cooling System Performance	3 ranked fixes
P0C31	Inverter B Cooling System Performance	3 ranked fixes
P0E81	Auxiliary Cooling System Coolant Temperature Sensor A Circuit	3 ranked fixes
P0E82	Auxiliary Cooling System Coolant Temperature Sensor A Circuit Range/Performance	3 ranked fixes
P0E83	Auxiliary Cooling System Coolant Temperature Sensor A Circuit Low	3 ranked fixes
P0E84	Auxiliary Cooling System Coolant Temperature Sensor A Circuit High	3 ranked fixes
P0EA7	Auxiliary Cooling System Performance	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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