C1001

Code

Generic C — Chassis

Steering Angle Sensor Circuit Malfunction

Brand: Generic

Type: C — Chassis

Views: UK: 15 EN: 29 RU: 19

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Damaged or corroded connector at the steering angle sensor
Broken, chafed or shorted wiring between sensor and control module
Poor ground or missing reference/5V supply to the sensor
Faulty steering angle sensor (internal failure)
Faulty ABS/ESC control module or input circuit
Recent steering, suspension, or column work without performing SAS relearn/calibration

Symptoms

ABS, ESC or traction control warning lamp illuminated
Stability control disabled or limited functionality
Fault stored in ABS/ESC module and possible limp-home behavior for stability systems
SAS angle value missing, erratic or stuck when reading live data
Vehicle may require a steering angle sensor relearn after repair
Possible intermittent faults or faults that appear when steering is turned/wheel moved

What to check

Read and record DTC(s) and freeze-frame data with a capable scan tool
Verify battery voltage is stable (>12 V) and charger not required during diagnosis
Inspect steering column area, sensor and harness for visible damage, corrosion or water ingress
Check connector pins for corrosion, bent pins, or poor mating; reseat connector
Scan live data: observe steering angle sensor value while turning the steering wheel slowly
Perform a wiggle test on harness and connector while monitoring live data or DTC status

Signal parameters

Reference supply typically ~5 V (varies by manufacturer) between reference and ground
Signal types: analog sin/cos pair (0.5–4.5 V range) or digital encoder/serial output; sensor reports angle/counts
At center steering wheel, angle output should be near center value (0° or mid-scale counts)
Live-data angle should change smoothly and proportionally as wheel is turned; no sudden jumps or dropouts
Typical ground near 0 V; excessive resistance or voltage on ground indicates poor return

Diagnostic algorithm

Connect a diagnostic scanner and capture DTCs, freeze frame and live SAS data. Note any related ABS/ESC codes.
Clear the code and re-create conditions to see if C1001 returns; observe when it sets (startup, during steering, after wash, etc.).
Visually inspect the sensor, harness, and connectors for damage, corrosion, water intrusion or improper routing.
With ignition on, measure reference voltage and ground at sensor connector. Confirm proper voltages per vehicle spec.
Probe the signal output while an assistant slowly turns the steering wheel. Expect a smooth, continuous change in voltage or counts. Use an oscilloscope if available to confirm waveform integrity.
Perform a wiggle test of the harness from sensor to module while watching live data and DTCs for intermittent opens/shorts.
Check continuity and resistance of signal, reference and ground wires back to the ABS/ESC module with power off. Repair any opens or high-resistance connections.
If wiring and connectors are good, swap or bench-test a known-good sensor (if available) or replace the steering angle sensor.
If sensor replacement performed, complete the manufacturer's steering angle sensor relearn/calibration procedure (many vehicles require the wheels straight and a scan tool).
Clear codes and road test to verify the repair. If code returns, investigate control module inputs or CAN communication as the next step.

Likely causes

Loose or corroded connector at the sensor or module
Open or short in sensor signal or reference wire caused by chafing/wear
Failed sensor electronics (common with high-mileage or water ingress)
No 5 V reference or poor ground at sensor due to harness/terminal issue
Control module input failing (less common) or CAN bus fault

Fault status

⚠️ Status

Steering Angle Sensor Circuit Malfunction — SAS signal out-of-range, missing or inconsistent. May disable ESC/traction control until repaired and sensor recalibrated.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-3.0 hours