Code
C0321
HUMMER
C — Chassis
Steering Angle Sensor Circuit Range/Performance
Views:
UK: 13
EN: 28
RU: 11
AI status
Completed
Completed
100%
Causes
- Faulty or failing steering angle sensor (SAS)
- Damaged wiring harness or connector (open, short, corrosion)
- Poor sensor ground or lost reference voltage
- Sensor misalignment or incorrect installation (no calibration)
- Intermittent module communication (CAN bus) or control module fault
- Mechanical steering play or binding affecting sensor movement
Symptoms
- ABS/ESC/Traction Control warning light illuminated
- Stability control or traction control disabled
- Steering angle or wheel alignment-related warnings displayed
- Cruise control or adaptive systems may be unavailable
- Inconsistent or incorrect steering wheel angle reading in scan tool
- Possible altered vehicle handling or unexpected stability corrections
What to check
- Read all stored codes and freeze frame with a full-function scan tool
- Check live steering angle sensor values at steering wheel centered and during left/right turns
- Inspect sensor connector and wiring for damage, corrosion, or loose pins
- Verify vehicle battery voltage and charging system while testing
- Confirm ABS/ESC module reports and CAN network status (no comm faults)
- Perform wiggle test on harness while observing live data for intermittent faults
Signal parameters
- Reference voltage (Vref): typically 5.0 V (verify exact spec in service manual)
- Center signal voltage: about 2.5 V for many analog SAS units (varies by design)
- Output type: analog 0–5 V or digital/CAN depending on sensor; consult OEM docs
- Full range: sensor provides angle spanning steering range (some up to ±720° total rotation)
- Resolution/accuracy: typically fractions of a degree; error if sudden jumps or out-of-range values occur
Diagnostic algorithm
- Connect scan tool, record C0321 and any related codes, note freeze frame data, then clear codes.
- With ignition ON, observe live steering angle data with wheel centered. Slowly turn wheel left/right and confirm smooth, proportional change without jumps or dropouts.
- Visually inspect steering angle sensor, column area, and harness for damage, pin corrosion, or loose connectors. Repair as needed.
- Verify Vref and ground at the sensor connector with a multimeter; check for ~5 V reference and good ground continuity to chassis.
- Probe the sensor signal while an assistant turns the wheel; check for smooth analog voltage sweep or valid digital/CAN messages. Look for intermittent loss or abrupt changes.
- Perform wiggle test on wiring and connectors while watching live data to find intermittent faults.
- If wiring and voltages are good but readings are incorrect, perform SAS relearn/calibration per OEM procedure (required after replacement or some steering work).
- If fault persists after calibration, replace the steering angle sensor. After replacement, re-calibrate the SAS and confirm fault does not return.
- If the new sensor still faults, suspect control module or CAN network faults; verify module communication and consider module-level diagnostics or replacement.
Likely causes
- Corroded/damaged connector at the steering angle sensor
- Steering angle sensor not calibrated after steering work or battery disconnect
- Open or short in the sensor signal/reference/ground circuit
- Failed steering angle sensor
- Faulty ABS/stability control module or CAN network error (less common)
Fault status
Status
Steering Angle Sensor Circuit Range/Performance — Sensor output outside expected range or inconsistent; may disable stability/traction functions until resolved.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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