🚨 Diagnostic Profile
- Vehicle/Equipment Make: GENERIC
- Technical Description: Power Steering Control Module Range/Performance
C0559 is a Chassis code monitored by the Electronic Brake Control Module (EBCM) or the dedicated Power Steering Control Module (PSCM), depending on platform architecture. This code indicates that the power steering control module has detected a signal — typically related to torque sensor input, motor position feedback, or steering angle correlation — that is outside of its expected operating range, or that does not perform as mathematically expected when cross-referenced with other chassis sensor inputs (such as the wheel speed sensors or steering angle sensor feeding the stability control system). This is a ‘Range/Performance’ fault, meaning the signal is present and electrically valid, but the value itself is implausible or inconsistent with other real-time chassis data being monitored by the ABS/Stability Control network. This typically results in a loss or reduction of power steering assist (the steering may become heavy), illumination of a steering assist warning indicator, and potentially setting related trouble codes in the traction control or stability control systems due to the loss of a reliable steering input signal.
🚨 Repair Difficulty Tier
- Difficulty Rating: Professional Only
This repair requires a bidirectional scan tool capable of accessing chassis-specific modules (not just generic OBD-II engine data) to view live steering torque, motor current, and angle correlation data. Diagnosis often requires comparing multiple live data streams between the PSCM and EBCM, as well as potential module calibration/relearn procedures after repair, which generally requires dealer-level or professional-grade diagnostic equipment.
🛠️ Resolution Steps
- Step 1: Preliminary Inspection
Begin by visually inspecting the wiring harness and connectors leading to the steering torque sensor and the power steering control module/motor assembly. Look for chafed wires, corrosion at connector pins, or damage near the steering column or motor housing from heat or road debris. Check for any physical obstruction or binding in the steering column that could cause abnormal mechanical resistance, which can be misread as a sensor performance fault. - Step 2: Diagnostic Verification
Connect a capable scan tool to the chassis data bus and pull live data for steering torque sensor voltage, steering angle, and motor feedback position. Compare the values while slowly turning the steering wheel lock-to-lock with the wheels off the ground; look for erratic jumps, dropouts, or values that do not correlate to the actual physical wheel position. Use a digital multimeter to verify steady reference voltage (typically 5V) and ground integrity at the torque sensor connector if live data appears frozen or implausible. - Step 3: Resolution & Reset Process
If wiring and connectors test correctly but the torque sensor or steering angle sensor itself returns erratic data, replace the faulty sensor assembly (often integrated into the steering column or rack). After installation, perform a steering angle sensor reset/relearn procedure and clear the stored code using the scan tool to confirm the fault does not reset during a steering angle calibration drive cycle.
📦 Parts, Labor, and Budget Estimates
- Required Components/Software: Steering torque/angle sensor assembly, replacement wiring harness pigtail (if damaged), bidirectional chassis scan tool with calibration/relearn capability
- Average Component Price: $150 – $450 USD
- Estimated Labor Hours: 1.5 – 3.0 hours (includes diagnostic time and calibration relearn)
- Total Estimated Budget: $300 – $750 USD