Fault Family System: Chassis (C-Codes) 20 SAE Codes

Variable Effort Power Steering Circuit

Diagnostic & Technical Explanation

Code C0079 (Variable Effort Steering) sets when the power steering control module cannot drive its variable-effort actuator, steering lock/safety actuator, or internal effort sensor to the commanded state, or the module itself reports a missing calibration, an incorrect replacement component, or a temperature outside its operating range. This system varies steering assist with vehicle speed and driver mode, so a fault here often shows up as unusually heavy or light steering effort rather than a total loss of assist. Physical causes include a failed actuator motor, a corroded connector at the steering rack or column module, or a control module that has not completed its post-repair configuration.

These 20 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 20 times.

Codes in this family (20)

Code	Definition	Repair coverage
C0079	Variable Effort Steering	4 ranked fixes
C0559	Power Steering Control Module Range/Performance – Rear	4 ranked fixes
C059A	Power Steering Control Module - Rear Missing Calibration	4 ranked fixes
C05D6	Power Steering Control Module Processor Performance	4 ranked fixes
C061C	Variable Effort Steering Actuator Control Circuit/Open	4 ranked fixes
C061D	Variable Effort Steering Actuator Control Circuit Low	4 ranked fixes
C061E	Variable Effort Steering Actuator Control Circuit High	4 ranked fixes
C061F	Variable Effort Steering Actuator Control Circuit Performance	4 ranked fixes
C0620	Variable Effort Steering Lock/Safety Actuator Control Circuit/Open	4 ranked fixes
C0621	Variable Effort Steering Lock/Safety Actuator Control Circuit Low	4 ranked fixes
C0622	Variable Effort Steering Lock/Safety Actuator Control Circuit High	4 ranked fixes
C0623	Variable Effort Steering Lock/Safety Actuator Control Circuit Performance	4 ranked fixes
C0624	Variable Effort Steering Sensor Circuit	4 ranked fixes
C0625	Variable Effort Steering Sensor Circuit Range/Performance	4 ranked fixes
C0626	Variable Effort Steering Sensor Circuit Low	4 ranked fixes
C0627	Variable Effort Steering Sensor Circuit High	4 ranked fixes
C0628	Variable Effort Steering Module Performance	4 ranked fixes
C0629	Variable Effort Steering Control Module Incorrect Component Installed	4 ranked fixes
C062A	Variable Effort Steering Module Temperature Too High	4 ranked fixes
C062B	Variable Effort Steering Module Temperature Too Low	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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