Code
C1720
Generic
C — Chassis
Steering Angle Sensor Signal Circuit Fault
Views:
UK: 9
EN: 20
RU: 7
AI status
Completed
Completed
100%
Causes
- Faulty steering angle sensor (internal fault or failed electronics)
- Open or shorted wiring between sensor and control module
- Corroded, loose, or damaged connector pins
- Loss of sensor supply voltage or ground
- Intermittent connection (broken wire, chafing, or connector contamination)
- Faulty steering column clockspring (if sensor routed through clockspring)
Symptoms
- ABS, ESP/traction control or steering warning lamp illuminated
- Loss or reduction of stability control / traction control functionality
- Steering assist warning or reduced/elevated steering effort (on some systems)
- Inaccurate or jumping steering angle reading in live-data or scan tool
- DTC C1720 stored; possibly other related codes
What to check
- Read all stored DTCs and freeze frame with an OEM-capable scan tool; record live-data steering angle values
- Verify obvious issues: damaged wiring, pin corrosion, bent pins, or disconnected connectors at sensor and module
- Check for additional ABS/ESP/CAN network codes that indicate communication faults
- Inspect clockspring (if applicable) for damage and correct routing of sensor wiring through column
- Check battery/charging system voltage and grounds before detailed signal testing
- Wiggle test wiring while observing live-data for intermittent changes
Signal parameters
- Supply voltage: typically 5V reference (verify OEM spec)
- Ground: continuity to chassis/vehicle ground
- Signal type: analog voltage (0.5–4.5 V typical) or digital (two-channel hall/AB outputs) depending on sensor design
- Center (straight-ahead) voltage/position should be stable and within manufacturer-specified center value
- Signal changes smoothly with steering input; no rapid dropouts or noise
- If digital/serial: steering angle messages expected on CAN/FlexRay at low frequency (tens of Hz); check message presence and valid checksum
Diagnostic algorithm
- Connect a scan tool and record C1720 plus any related codes and live-data (steering angle, wheel speeds, yaw rate).
- Verify symptom: turn steering wheel slowly while watching live-data. Note whether angle value follows wheel movement smoothly and returns to center.
- Visually inspect sensor, connector, and wiring harness for damage, corrosion, or pin push-out; repair obvious faults.
- Check reference voltage and ground at the sensor connector with key ON; compare to OEM spec. If supply/ground missing, trace back to fuse/relay/module.
- Back-probe signal wire(s) and observe with oscilloscope or DMM while turning wheel. Look for expected analog waveform or proper differential/digital signals.
- Perform a continuity and resistance check of the signal and power wires between sensor and module to find opens or shorts (including shorts to power/ground).
- If wiring and power/ground are good but signal is out-of-spec, replace the steering angle sensor. If sensor is integrated into clockspring, replace the clockspring assembly per OEM procedure.
- After repair or replacement, perform steering angle calibration/learn procedure with scan tool as required by manufacturer.
- Clear codes and road-test to confirm proper operation and that C1720 does not return.
- If fault persists with correct sensor signals, investigate ABS/ESP/steering control module and CAN bus diagnostics (check for module faults or corrupted messages).
Likely causes
- Corroded/loose connector at the steering angle sensor
- Broken or shorted signal wire between sensor and module
- Failed steering angle sensor
- Missing/incorrect steering angle calibration after battery disconnect or repair
Fault status
Status
Steering Angle Sensor Signal Circuit Fault — invalid or missing steering angle input. Check sensor, wiring, supply/ground, clockspring, communications, and perform steering angle calibration after repair.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
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