C1803

Code

Generic C — Chassis

Steering Angle Sensor Circuit Fault

Brand: Generic

Type: C — Chassis

Views: UK: 15 EN: 27 RU: 13

AI status

Completed

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Page language: EN

Causes

Damaged or corroded wiring or connector to the steering angle sensor
Poor or missing power or ground to the sensor
Failed steering angle sensor (potentiometer, encoder, or module)
Loss of communication on vehicle network (CAN/LIN) between sensor and control module
Steering column physical damage or sensor misalignment after service
Failed ABS/ESP control module or internal circuit fault

Symptoms

ABS, ESC or traction control warning lamp illuminated
Stability/traction control disabled or operates incorrectly
Steering angle parameter shows incorrect or no movement on scan tool
Unexpected ABS/traction intervention or degraded braking stability
Possible stored/active limp or reduced-driving modes related to stability systems

What to check

Read and record DTCs and freeze frame with a capable scan tool (ABS/ESP module)
Check live steering angle sensor data while turning wheel; compare to steering wheel movement
Visually inspect sensor connector and wiring for damage, corrosion, or pin push-out
Backprobe sensor power (reference) and ground; verify correct voltages (see signal_params)
Perform wiggle test on harness and connector while watching live data for intermittent faults
Check for related network codes (U-codes) indicating CAN/LIN communication loss

Signal parameters

Reference supply typically 5 V (varies by OEM); ground 0 V
Analog sensors often output approx. 0.5–4.5 V across travel; digital sensors provide CAN/LIN messages
Some sensors provide two-channel (A/B) differential outputs or PWM signals — watch for complementary pulses
Expected change of live sensor value proportional to steering wheel rotation; centered value near specified midpoint
CAN bus: normal operation indicated by periodic steering angle messages and no bus errors

Diagnostic algorithm

Connect scan tool to ABS/ESP module. Read and record all stored and pending codes (include network/U-codes).
Verify symptom: with ignition ON, monitor live steering angle data while slowly turning steering wheel. Note if value changes smoothly and returns to center.
Inspect sensor connector and harness for damage, corrosion, pin deformation, or rubbing points; repair as needed.
Backprobe sensor connector: measure reference voltage, signal(s), and ground with key ON (engine off). Compare to expected ranges in signal_params.
Wiggle wiring and connectors while observing live data and DTC status to locate intermittent faults.
If sensor is powered but signal is absent or out of range, substitute known-good sensor or temporarily bridge connector (if safe) to confirm fault.
Check for CAN/LIN communication faults: verify bus integrity, termination, and module communication. Repair bus faults first.
Inspect/verify steering column installation, clock spring, and any recent repairs that could have disturbed sensor alignment.
If repairs or replacements are performed, erase codes, perform required steering angle sensor calibration or zero-point learning per service manual, then perform road test and re-scan.
If fault persists after replacing sensor and repairing wiring, consider ABS/ESP control module internal fault and test or replace per OEM procedures.

Likely causes

Broken/shorted wire in harness at steering column (most common)
Loose or corroded connector at sensor or control module
Sensor lost reference voltage or ground
Sensor internal failure after impact or wear
Recent steering column removal or clock spring replacement without recalibration
Intermittent CAN bus connection or module communication error

Fault status

⚠️ Status

Stored when the steering angle sensor signal is missing, out of expected range, intermittent, or communication between the sensor and control module is lost. May disable stability/traction functions until resolved.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours