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DTC code

C1231

Speed Wheel Sensor Rear Center Circuit Open

Technical guide

Symptoms

  • ABS
  • traction control and/or stability control (VSC) warning lights illuminated
  • stability control system behaving erratically or deactivating
  • traction control engaging unexpectedly
  • vehicle stability control not functioning properly.

Probable causes

  • Faulty steering angle sensor
  • damaged wiring or connectors in the steering angle sensor circuit
  • steering angle sensor power supply fault
  • corrosion or contamination at the sensor or its connections
  • lost sensor calibration/zero point
  • skid control ECU (brake actuator assembly) malfunction.

Diagnostic steps

  1. Read DTCs from the ABS/VSC system, clear them, cycle the ignition and confirm whether C1231 returns and whether any CAN communication DTCs appear.
  2. Road-test at approximately 35 km/h turning the steering wheel left and right and check that no speed sensor or yaw rate sensor DTCs set (Toyota procedure).
  3. Inspect the steering angle sensor connector (behind the steering wheel/column cover) for looseness, damage or corrosion; repair as needed.
  4. With the sensor connector disconnected, check the sensor power supply: voltage at the IG and BAT terminals to body ground should be 11-14 V (Toyota spec).
  5. Check the sensor ground terminal resistance to body ground: below 1 ohm (Toyota spec).
  6. If power and ground are good but the fault persists, replace the steering angle sensor, then perform the zero point calibration/alignment procedure so the new sensor reports correctly.
  7. If the code still returns with a known-good calibrated sensor, suspect the skid control ECU (brake actuator assembly).

Cross-checked technical synthesis (QA). It does not replace the manufacturer's procedure.

Models most reported with this code (NHTSA)

Toyota Sequoia 6

Count of distinct owner complaints mentioning the code. US data — same engines, same failures.

AI here is a librarian: this page shows only what mechanics confirmed, or says “unknown”. It never suggests a diagnosis — MECCANIC interprets the code, never your car.

0 confirmed cases on C1231

Nothing confirmed yet for this code. No guess is offered on purpose.

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