MechanicDB
Fault Family System: Powertrain (P-Codes) 7 SAE Codes

AC Compressor Control Circuit

Diagnostic & Technical Explanation
Code P0645 (A/C Clutch Relay Control Circuit) sets when the ECM detects an open circuit, out-of-range current, or a performance fault while driving the A/C compressor clutch relay or a variable-displacement compressor's control solenoid. Causes are a failed clutch coil or control solenoid, a bad relay, a seized compressor, or damaged control wiring.

These 7 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 7 times.

Codes in this family (7)

CodeDefinitionRepair coverage
P0645A/C Clutch Relay Control Circuit4 ranked fixes
P0646A/C Clutch Relay Control Circuit Low4 ranked fixes
P0647A/C Clutch Relay Control Circuit High4 ranked fixes
P06A0Variable A/C Compressor Control Circuit4 ranked fixes
P06A1Variable A/C Compressor Control Circuit Low4 ranked fixes
P06A2Variable A/C Compressor Control Circuit High4 ranked fixes
P265FVariable A/C Compressor Control Circuit Range/Performance4 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: