C1223 - FAULT CODE - OBD2

C1223 BUICK, CADILLAC, CHEVROLET, GMC, PONTIAC: LEFT REAR WHEEL SPEED SENSOR INPUT SIGNAL IS ZERO

The EBCM (Electronic Brake Control Module) sends an ignition signal to the wheel speed sensors. This kind of sensor tells the controller at what speed the corresponding wheel rotates through a square wave signal. To carry out its performance, each Wheel Speed Sensor has a reluctor ring. When this ring moves, it interrupts a magnetic field. With each interruption, some pulses are produced. These pulses are sent to the EBCM and the controller that needs them to calculate the speed at which the wheel is rotating.

The diagnostic code C1223 OBDII is set when the EBCM detects a malfunction in the Left Rear Wheel Speed Sensor. This condition is detected because there is no signal from the left rear wheel speed sensor or the signal is zero.

• Check Engine lamp ON.
• The Anti-lock wheel system warning lamp turns on.
• The dashboard displays a vehicle speed different from the real one.
• The brake switch experiences varying levels of tapping.

Reasons to store the C1223 OBD2 fault code C1223:

• The hub assembly (The left rear wheel speed sensor is part of the hub assembly) may be damaged.
• The left rear wheel speed sensor wires or connectors may be faulty.
• The left rear wheel speed sensor may be defective.

To troubleshoot DTC C1223 OBDII, try this:

• Consult the Technical Service Bulletins.
• Check the wiring related to the left side Rear Wheel Speed Sensor. Check these for common shortages causing wear or burns. Fix if necessary.
• Make electrical checks on the Wheel Speed Sensor circuit by using the appropriate tools. If you find voltages different from those specified by the manufacturer, make the appropriate corrections.
• Check the integrity of the left rear wheel speed sensor, taking into account the diagnostic steps indicated by the manufacturer. If you find some damage to the sensor, consider replacing it.