C1155 - SPEED WHEEL SENSOR LF INPUT CIRCUIT FAILURE

DTC C1155 OBDII is a factory-specific code whose setting occurs at the moment that the PCM (Powertrain Control Module) founds an error in the circuit that relates to the Left Front Wheel Speed Sensor. This type of sensor is a Hall effect sensor, which creates magnetic fields once the teeth of a reluctor ring pass in front of the sensor as the ring rotates with the wheel. Although this ring is usually attached to the drive shaft, it is also incorporated into the wheel bearing.

The teeth of the reluctor rings are closely related to the wheel speed sensors and are located evenly around the circumference of the ring. The signals generated as the ring rotates are evenly spaced, making it possible for the PCM to count the number of signals produced for each complete revolution of a wheel and the number used as a basis for the PCM to calculate the rotational speed of each wheel.

All Wheel Speed Sensors are first connected to the ABS Brake Control Module and from there the connection goes out to the PCM. This is important because the ABS module uses the rotational speeds of each individual wheel to determine the proper braking forces, thus preventing the lock-up of one or more wheels in difficult driving conditions. Safety-critical systems depend entirely on accurate signals from the wheel speed sensors. In the event of a sensor or sensor circuit failure, the PCM or ABS will recognize that effective control of these safety systems has not been achieved.

• Check Engine lamp illuminated.
• Traction control and stability control warning lamps are illuminated.
• Multiple fault codes
• The anti-lock wheel system cannot be activated.
• Stability control and cruise control do not function properly.

The reasons for storing the C1155 OBD2 fault code are:

• The Speed Wheel Sensor circuit may have damage to its wires or connectors.
• The Speed Wheel Sensor LF may be faulty.
• The ABS Control Module may have damage.

The steps to give you the respective solution to the C1155 OBDII error code are:

• As a first step, you should consult the Technical Service Bulletins (TSB).
• Perform a thorough check of the wiring related to the left front wheel speed sensor for burns or wear. You should also check the condition of the connector and its pins. Repair or replace as necessary.
• Check the condition of the Left Front Wheel Speed Sensor. To do this, use a DVOM and refer to the diagnostic steps for this sensor. If you determine that it is defective, replace it.