MechanicDB
Fault Family System: Powertrain (P-Codes) 10 SAE Codes

Engine Coolant Heater Circuit

Diagnostic & Technical Explanation
Code P01E8 (Engine Coolant Heater A Control Circuit/Open) sets when the ECM detects an open circuit, out-of-range current, or excessive driver temperature while controlling the electric engine coolant heater used for cold-climate pre-heat or emissions warm-up assistance. Causes are a failed heater element, a shorted driver circuit, or corroded connector pins.

These 10 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 10 times.

Codes in this family (10)

CodeDefinitionRepair coverage
P01E8Engine Coolant Heater A Control Circuit/Open3 ranked fixes
P01E9Engine Coolant Heater A Control Circuit Low3 ranked fixes
P01EAEngine Coolant Heater A Control Circuit High3 ranked fixes
P01EBEngine Coolant Heater A Control Circuit Performance3 ranked fixes
P01ECEngine Coolant Heater B Control Circuit/Open3 ranked fixes
P01EDEngine Coolant Heater B Control Circuit Low3 ranked fixes
P01EEEngine Coolant Heater B Control Circuit High3 ranked fixes
P01EFEngine Coolant Heater B Control Circuit Performance3 ranked fixes
P01F8Engine Coolant Heater A Control Circuit Driver Current/Temperature Too High3 ranked fixes
P01F9Engine Coolant Heater B Control Circuit Driver Current/Temperature Too High3 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: