C1156

Code

Other C — Chassis

Speed Wheel Sensor LF Circuit Open

Brand: Other

Type: C — Chassis

Views: UK: 18 EN: 25 RU: 25

AI status

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Page language: EN

Causes

Broken or disconnected wiring between LF wheel speed sensor and ABS module
Corroded or loose sensor connector or terminals
Failed/defective LF wheel speed sensor (internal open)
Damaged sensor tone ring or hub that prevents signal generation
Poor ground or blown fuse affecting sensor power/reference (for active sensors)
Intermittent connector contact from water/road contamination

Symptoms

ABS and/or traction control warning lamp illuminated
Possible speedometer or cruise control issues (in some vehicles)
ABS may not engage or may behave incorrectly under braking
Traction/stability control disabled or limited
Diagnostic trouble code C1156 stored in ABS/traction control module

What to check

Scan ABS module for stored codes and freeze frame data; note status bits
Perform a careful visual inspection of LF wheel sensor, tone ring, harness and connector
Check for corrosion, bent pins, water intrusion or broken wires at the connector
Wiggle wiring and connector while monitoring live wheel speed data for dropouts
Measure continuity between the sensor connector and the ABS module harness connector
Measure sensor resistance and compare to specification (or compare with same-side/right-front sensor)

Signal parameters

Passive (magnetic) sensor: typical resistance range ~800–2500 Ω (varies by vehicle) — produces AC voltage when wheel spins (0.1–2.0 Vrms at low speed). Verify OEM spec.
Active (Hall) sensor: reference supply typically ~5 V (check with key ON), signal toggles between ~0–5 V when wheel rotates. Open circuit may show no output or no reference.
Continuity: near 0 Ω between sensor housing ground and chassis ground (if sensor ground is separate); otherwise no open between sensor pins and module pins.
If circuit is open: infinite resistance between sensor terminals or between sensor and module connector.

Diagnostic algorithm

Retrieve and record all stored codes and live data from the ABS module; note LF wheel speed reading with ignition ON and while driving slowly.
Visually inspect the LF sensor, tone ring, harness routing, and connector for damage, corrosion, or disconnection.
With vehicle safely supported, unplug the LF sensor connector. Check for corrosion, pushed-back pins or water. Repair or clean as needed.
Use a multimeter to measure resistance across sensor terminals. If passive sensor shows open (infinite), replace sensor. If active, check for reference voltage and ground with key ON.
Check continuity between the sensor connector pins and the ABS module wiring connector pins. Repair any open wires (splice or replace harness) found.
If wiring is intact, spin the wheel and measure sensor output (AC for passive, pulsed DC for active). No measurable signal indicates sensor or tone ring issue.
If wiring and sensor check good, inspect tone ring/reluctor for damage or missing teeth and verify correct air gap. Repair or replace hub/reluctor if necessary.
After repair, clear codes, perform a road test while monitoring wheel speed sensor data to confirm proper operation and that C1156 does not return.
If the fault persists after sensor and wiring repairs, test or consult procedure for ABS module input driver; consider module diagnosis by a specialist.

Likely causes

Wiring harness chafed or fractured at suspension pivot or near wheel
Connector separated or pins pushed back/corroded at sensor
Sensor damaged by impact, rust, or hub corrosion
Open internal sensor winding (sensor resistance out of range)
Short/open in sensor power/reference circuit (for active sensors)
Connector filled with water or salt causing open circuit

Fault status

⚠️ Status

Left Front wheel speed sensor circuit open — no valid signal detected from LF wheel speed sensor. ABS/traction control disabled for that input until fault is resolved.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours

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