Code
C1B1A
Generic
C — Chassis
Steering Torque Sensor Circuit Intermittent
AI status
Completed
Completed
100%
Causes
- Intermittent wiring connection (broken/loose/shorted conductor)
- Corroded or damaged connector pins
- Faulty steering torque sensor
- Poor ground or reference voltage loss
- Intermittent power supply (fused circuit, ignition feed)
- Intermittent CAN/LIN bus or module communication fault
Symptoms
- Intermittent EPS/Power Steering warning lamp or message
- Temporary loss or fluctuation of steering assist (heavy or grabby steering)
- Stability control/traction control warning or degraded function
- Occasional steering feel changes when turning wheel
- Intermittent fault memory entries, may not be present continuously
- Possible degraded driver-assist features (lane keep, park assist)
What to check
- Read all related DTCs and freeze frame/live data with a capable scan tool
- Monitor live steering torque sensor values while slowly turning the steering wheel (look for dropouts, spikes, or wild values)
- Visually inspect connectors, wiring, and harness routing through the steering column and to the module
- Check for corrosion, bent pins, or water ingress at connectors
- Verify battery voltage and ignition-switched supply to sensor circuits
- Check module and chassis grounds for tightness and corrosion
Signal parameters
- Typical wiring: 3-wire or 2-wire Hall/differential sensor + reference (typically 5 V), ground, and signal/CAN output
- Expected resting signal (analog Hall): ~2.4–2.6 V mid‑rail; range under torque ~0.5–4.5 V (vehicle dependent)
- Digital/can-based sensors: periodic CAN/LIN messages at tens to low hundreds Hz; message should be stable with valid CRC
- Supply rail tolerance: reference supply ~5 V ±5% (check at connector under load)
- Signal noise/interrupts: intermittent drops to 0 V, spikes, or loss of message indicate fault
Diagnostic algorithm
- Connect a full-function scan tool and note occurrence frequency and related codes; record freeze frame and live data
- Visually inspect harness and connectors at the torque sensor, steering column, and receiving module for damage, corrosion, or looseness
- With ignition on, verify reference supply voltage and ground at the sensor connector; compare to vehicle specifications
- Monitor live torque sensor output while slowly turning the steering wheel; watch for momentary signal loss, spikes, or implausible values
- Perform a wiggle/steer test: gently move wiring and connectors while watching live data to reproduce the intermittent fault
- If intermittent behavior observed, capture waveform with an oscilloscope on signal and reference lines during steering movement to confirm electrical fault
- Check related modules for communication errors (CAN/LIN) and inspect network grounds and power supplies
- If wiring and connectors check good, substitute known-good sensor if available or repair/replace sensor harness and retest
- If intermittent continues after sensor and wiring verified, consider module diagnostics or reflash per manufacturer procedures; avoid replacing modules without comprehensive testing
Likely causes
- Broken or chafed wire in steering column harness (inner wheel/column movement)
- Loose or corroded connector at torque sensor or steering column module
- Partial short to battery or ground when steering is turned (intermittent)
- Worn/failed torque sensor (internal contact or Hall element intermittent)
- Poor ground at module chassis or body ground point
- Intermittent loss of 5V reference or ignition-switched supply to sensor
Fault status
Status
Intermittent/occasional loss or corruption of steering torque sensor signal detected.
Repair difficulty: Medium
Diagnostic time: 1.0 - 2.5 hours
Similar codes
Repair manuals
Brands with available manuals
7,900
The library contains 7,900 repair and diagnostic manuals. Choose a brand to open the full manual tree by year, model and trim.
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email