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C0551 – Longitudinal Acceleration Sensor Circuit Open (OBD2)

C0551 means "Longitudinal Acceleration Sensor Circuit Open". The control unit sees an open circuit: the electrical connection to the yaw rate and acceleration sensor is interrupted, so no current can flow when the component is commanded or read.

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C0551 quick summary

Fault codeC0551
MeaningLongitudinal Acceleration Sensor Circuit Open
SystemChassis
VehiclesGeneric OBD2
SeverityMedium
Can I drive?Yes, carefully. ESP and traction control are usually disabled, so drive gently, especially on wet or slippery roads.
Repair cost€0 – €600

How the yaw rate and acceleration sensors work

The stability control system measures how the car rotates and accelerates; these codes mean a yaw rate, lateral, longitudinal, vertical or multi-axis acceleration sensor is faulty or implausible, or the stability system has been active for too long.

The yaw rate sensor measures how fast the car rotates around its vertical axis; acceleration sensors measure lateral (sideways), longitudinal (forward/back) and sometimes vertical and roll movement. On modern cars these are combined in one multi-axis sensor module, often integrated in the airbag module or the ESP unit.

The ESP compares these values with the steering angle and wheel speeds to detect understeer and oversteer. Codes report circuit faults, range and intermittent faults, implausible values compared with the other sensors, a missing calibration and stability control interventions lasting too long.

Sensors must be mounted firmly and level. A loose bracket, a sensor fitted the wrong way round after interior work, water in the connector or a missing calibration after replacement are typical causes.

C0551 is a chassis code in the standard (SAE) numbering. Some manufacturers – for example GM, Opel and Ford on certain models – use their own meanings for some C codes, so always check the text your scan tool shows for your vehicle.

Symptoms of C0551

  • ESP and traction control lights on
  • ESP intervenes without reason, especially in corners
  • Hill-hold or adaptive cruise not available
  • Code appears after interior, seat or airbag module work
  • Code appears after module replacement

Most common causes of C0551 (most likely first)

Mechanic's Pro Tip

Calibrate the sensors with the car on level ground and stationary – calibrating on a slope stores a wrong zero point and the code comes back.

  1. 1.Unplugged, loose or corroded connector

    Most likely

    Often after previous repair work in the area.

  2. 2.Broken wire in the harness

    Typical at bends, near the engine mounts and where the harness rubs on brackets.

  3. 3.Burnt-out winding or internal break in the yaw rate and acceleration sensor

  4. 4.Missing calibration after sensor or module replacement

  5. 5.Loose, damaged or wrongly fitted sensor or bracket

  6. 6.Faulty yaw rate or acceleration sensor

  7. 7.Implausible input from steering angle or wheel speed sensors

    The ESP compares all sensors – a fault elsewhere can be blamed on this sensor.

Step-by-step diagnostic guide

  1. 1

    Read codes and live values

    Read the ESP module (and airbag module if the sensor is integrated there). With the car stationary on level ground, yaw rate and accelerations should be about zero.

  2. 2

    Measure resistance and continuity

    Unplug the yaw rate and acceleration sensor and measure its resistance across the terminals. An infinite (OL) reading confirms an internal break. If the component is fine, check each wire back to the control unit for continuity.

    Multimeter: Solenoids and heaters typically read a few ohms to a few dozen ohms; "OL" means open. Wire continuity: below about 1 Ω.

  3. 3

    Check mounting

    Check that the sensor and bracket are tight, undamaged and fitted in the correct orientation.

  4. 4

    Check wiring and power

    Check the connector for moisture and the supply, ground and bus lines.

    Multimeter: Stationary on level ground: yaw rate about 0 °/s and lateral acceleration about 0 m/s².

  5. 5

    Check related sensors

    Rule out steering angle and wheel speed sensor faults, which can make this sensor appear implausible.

  6. 6

    Replace and calibrate

    Replace the sensor if faulty and run the yaw rate/acceleration sensor calibration with the scan tool on level ground.

Frequently asked questions

Can I keep driving with C0551?

Yes, carefully. ESP and traction control are usually disabled, so drive gently, especially on wet or slippery roads.

How much does it cost to fix C0551?

Typical repair costs are 0 € – 600 €, depending on the cause and the vehicle. The most common fixes are: unplugged, loose or corroded connector; broken wire in the harness; burnt-out winding or internal break in the yaw rate and acceleration sensor. Always confirm the cause with the tests above before buying parts.

Where is the yaw rate sensor?

Usually near the car's centre of gravity – under the centre console or a front seat – or integrated in the airbag or ESP module.

Is it safe to drive without ESP?

The car drives and brakes normally, but without the stability control safety net. Drive carefully and repair it soon.

What is the difference between C0551 and similar codes?

C0551 belongs to a group of codes for the same component that differ in the type or location of the fault: C0523 – Multi-Axis Acceleration Sensor Module B Intermittent/Erratic; C0524 – Multi-Axis Acceleration Sensor Module B Correlation; C0525 – Multi-Axis Acceleration Sensor Module B; C0552 – Longitudinal Acceleration Sensor Range/Performance; C0553 – Longitudinal Acceleration Sensor Circuit Low; C0554 – Longitudinal Acceleration Sensor Circuit High. The tests on this page apply to the whole group; the type of fault tells you where to start.

Related fault codes

This guide is for information only. Working on vehicles can be dangerous — if you are unsure, have the car checked by a qualified mechanic. Values can differ between model years; always check the manufacturer's repair information.