Buick Regal: DTC C0750, C0755, C0760, or C0765

Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC C0750 03

Left Front Tire Pressure Sensor Low Voltage

DTC C0750 29

Left Front Tire Pressure Sensor Too Few Pulses

DTC C0750 39

Left Front Tire Pressure Sensor Internal Malfunction

DTC C0755 03

Right Front Tire Pressure Sensor Low Voltage

DTC C0755 29

Right Front Tire Pressure Sensor Too Few Pulses

DTC C0755 39

Right Front Tire Pressure Sensor Internal Malfunction

DTC C0760 03

Left Rear Tire Pressure Sensor Low Voltage

DTC C0760 29

Left Rear Tire Pressure Sensor Too Few Pulses

DTC C0760 39

Left Rear Tire Pressure Sensor Internal Malfunction

DTC C0765 03

Right Rear Tire Pressure Sensor Low Voltage

DTC C0765 29

Right Rear Tire Pressure Sensor Too Few Pulses

DTC C0765 39

Right Rear Tire Pressure Sensor Internal Malfunction

Circuit/System Description

The tire pressure monitor system has a radio frequency (RF) transmitting pressure sensor in each wheel/tire assembly. As vehicle speed increases, centrifugal force puts the sensor into Drive mode. The sensors send the tire pressure data to the remote control door lock receiver (RCDLR) which in turn translates the received sensor data into sensor presence, sensor mode, and tire pressure before passing it onto the body control module (BCM). Once vehicle speed is greater than 40 km/h (25 MPH), the BCM waits for the first sensor to go into Drive mode, then checks if all sensors have gone into Drive mode. If one or more sensors does not go into these modes, or does not transmit at all, the BCM will set DTC C0750, C0755, C0760, or C0765 respectively.

Conditions for Running the DTC

Vehicle speed is greater than 40 km/h (25 MPH).

Conditions for Setting the DTC

• A sensor does not transmit or transmits invalid data to the BCM.
• A sensor low battery condition.

Action Taken When the DTC Sets

• The tire pressure monitor system indicator icon on the instrument cluster flashes for 1 min and then remains illuminated after the ignition switch is cycled ON and the instrument cluster bulb check is complete.
• If equipped, the driver information center displays a service tire monitor type message.

Conditions for Clearing the DTC

A current DTC will clear when the malfunction is no longer present and one ignition cycle occurs.

Diagnostic Aids

• Some aftermarket wheel valve stem holes are located further from the wheel rim than original equipment wheels. When using the tire pressure monitor special tool to activate a sensor, ensure the tool is placed along the tire sidewall and no further than 15 cm (6 in) from the sensor and the antenna is aiming upward.
• Aftermarket wheel valve system locations can cause a sensor to not function correctly.
• A sensor may have been damaged due to a previous wheel/tire service or flat tire event.
• The use of other than GM approved tire sealants can obstruct the sensor pressure sensing port and cause inaccurate tire pressure readings. If this condition is verified, remove the sealer from the tire and replace the sensor.
• Occasionally sensor transmissions are not received by the BCM due to vehicle level radio frequency interference from items such as but not limited to aftermarket ignition systems, DVD players, CB radios, or metallic type window tinting.
• The sensor activation procedure may have to be repeated up to 3 times before determining a sensor is malfunctioning. In the event a particular sensor information is displayed on the special tool upon activation but the horn does not chirp, it may be necessary to rotate the wheel valve stem to a different position due to the RF signal being blocked by another component.
• Occasionally sensors can become mislocated due to previous tire rotations where the sensor learn procedure was not performed. Always learn the sensors to ensure the DTC set is for that actual physical corner of the vehicle. Refer to Tire Pressure Indicator Sensor Learn.
• A sensor low battery condition will set a sensor DTC but will not illuminate the low tire pressure indicator or display a message on the driver information center, if equipped. The sensor battery condition can be verified in the scan tool BCM data list. If a sensor low battery condition is indicated on the scan tool, the sensor will need to be replaced. Refer to Tire Pressure Indicator Sensor Replacement.
• The Hit Rate of the sensor will help confirm the success rate at which the sensor transmission is being received. A low Hit Rate will signal that there may be interference. Refer to Tire Pressure Rolling Count Procedure.

Reference Information

Description and Operation

Tire Pressure Monitor Description and Operation

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Verify there are no communication DTCs set along with DTC C0750, C0755, C0760, and C0765.

• If a communication DTC is set

Refer to Diagnostic Trouble Code (DTC) List - Vehicle.

• Go to next step: If a communication DTC is not set

2. Verify the scan tool Tire Pressure Sensor Rolling Count parameter of all 4 tire pressure sensors is above 50%.

• If the Tire Pressure Sensor Rolling Count parameter is below 50% on one or more tires

NOTE: When moving the tire pressure sensor to a different location on the vehicle, keep the tire pressure sensor with the original tire it is installed in.

1. Move the appropriate tire to a different location on the vehicle and verify the Tire Pressure Sensor Rolling Count has increased. Refer to Tire and Wheel Removal and Installation.
   • If Tire Pressure Sensor Rolling Count parameter does not increase after moving tire to different location, replace the appropriate B2 Tire Pressure Sensor and perform the Tire Pressure Indicator Sensor Learn.
   • If Tire Pressure Sensor Rolling Count parameter does increase after moving tire to different location, check for any aftermarket devices that could be causing interference to the tire pressure sensor signal.

• Go to next step: If the Tire Pressure Sensor Rolling Count parameter is above 50% on one or more tires

3. Verify if all 4 tire monitor pressure sensor DTCs are not set.

• If 2 or more tire monitor pressure sensor DTCs are set, test the keyless entry antenna for proper operation, or if antenna is properly seated. Refer to Keyless Entry System Malfunction (Active) Keyless Entry System Malfunction (Passive)

4. Perform the Tire Pressure Indicator Sensor Learn.

5. Verify the scan tool Tire Pressure Sensor Mode parameters change to Drive while driving the vehicle above 40 km/h (25 mph) for greater than 2 min.

• If a Tire Pressure Sensor Mode parameter does not change to Drive

1. Replace the appropriate B2 Tire Pressure Sensor.
2. Perform the Tire Pressure Indicator Sensor Learn.

• Go to next step: If the Tire Pressure Sensor Mode parameter changes to Drive

6. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• Tire Pressure Indicator Sensor Replacement
• Tire Pressure Indicator Sensor Learn

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