C0750

DTC C0750, C0755, C0760, or C0765 (Without UH3)

Diagnostic Instructions

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

DTC Descriptors
DTC C0750
- Left Front Low Tire Pressure Sensor

DTC C0755
- Right Front Low Tire Pressure Sensor

DTC C0760
- Left Rear Low Tire Pressure Sensor

DTC C0765
- Right Rear Low Tire Pressure Sensor

Circuit/System Description

The tire pressure monitor (TPM) system has a radio frequency (RF) transmitting pressure sensor in each wheel/tire assembly. As vehicle speed increases, centrifugal force closes the sensors internal roll switch, which puts the sensor into Rolling mode. The remote control door lock receiver (RCDLR) receives and translates the data contained in the tire pressure sensor RF transmissions into sensor presence, sensor mode, and tire pressure. Once vehicle speed is greater than 40km/h (25 mph), the RCDLR waits for the sensors to go into rolling mode. If one or more sensors do not go into rolling mode, or do not transmit at all, the RCDLR will set DTC C0750, C0755, C0760, or C0765 respectively.

Conditions for Running the DTC

Vehicle speed is 40 km/h (25 mph) or greater for 2 minutes.

Conditions for Setting the DTC

A sensor does not transmit for 18 minutes.

Action Taken When the DTC Sets

* The tire pressure monitor indicator icon on the instrument panel cluster (IPC) flashes for 1 minute and then remains illuminated after the ignition switch is cycled ON and the IPC bulb check is complete.
* The driver information center (DIC) displays the suspect tire pressure as dashes.
* The DIC displays the servive tire monitor type message.

Conditions for Clearing the DTC

* A current DTC will clear when the malfunction is no longer present and 1 ignition key cycle occurs.
* The RCDLR automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Diagnostic Aids

* Some aftermarket wheel valve stem holes are located further from the wheel rim than original equipment wheels. When using the TPM special tool to activate a sensor, ensure the tool antenna is no further than 15 cm (6 in) from the sensor and is aiming upward.
* Aftermarket wheel valve stem 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. Refer toTire Pressure Indicator Sensor Replacement Service and Repair.
* Occasionally sensor transmissions are not received by the RCDLR due to vehicle level RF 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's 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 is being blocked by another component.
* Occasionally sensors can become mislocated due to previous tire rotations where the sensor learn procedure was not performed or stray sensor transmissions have been received from other vehicles. 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 (Without UH3) Tire Pressure Indicator Sensor Learn (Without UH3)Tire Pressure Indicator Sensor Learn (With UH3) Tire Pressure Indicator Sensor Learn (With UH3).
* 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 DIC, if equipped. The sensor battery condition can be verified in the scan tool RCDLR 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 Service and Repair.

Reference Information
Description and Operation

Tire Pressure Monitor Description and Operation Description and Operation
Electrical Information Reference

* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs

Scan Tool Reference

Control Module References Control Module References for Scan Tool Information
Special Tools

EL-46079/J-46079 Tire Pressure Monitor Diagnostic Tool

Circuit/System Verification

1. Using the EL-46079/J-46079 , activate each tire pressure sensor and record each sensors transmission data and physical location. Verify EL-46079/J-46079 displays the 8-digit ID number, accurate tire pressure +/- 27.6 kPa (4 psi), Learn Mode, and at least a 1/4 graph signal strength displayed.

• If any of the parameters listed above are not displayed, replace the suspect tire pressure sensor.

2. With the scan tool, verify tire pressure sensors ID and locations displayed on the scan tool match the IDs and locations recorded from the special tool.

• If the IDs and locations do not match, perform the Tire Pressure Indicator Sensor Learn (Without UH3) Tire Pressure Indicator Sensor Learn (Without UH3)Tire Pressure Indicator Sensor Learn (With UH3) Tire Pressure Indicator Sensor Learn (With UH3).

3. Enable the TPM learn mode. Use the EL-46079/J-46079 in simulate mode to learn 4 simulated sensor transmissions into the RCDLR. Verify that all 4 simulated sensor locations, IDs, and tire pressures displayed on the TPM special tool match the corresponding scan tool parameters displayed.

• If the scan tool does not match, replace the RCDLR.

4. Test drive the vehicle above 40 km/h (25 mph) for greater than 2 minutes. With the scan tool, observe the suspect Pressure Sensor Mode data parameter. Verify the sensor mode changes to Rolling.

• If the Pressure Sensor Mode does not change, replace the suspect tire pressure sensor.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.

* Tire Pressure Indicator Sensor Replacement Service and Repair
* Tire Pressure Indicator Sensor Learn (Without UH3) Tire Pressure Indicator Sensor Learn (Without UH3)Tire Pressure Indicator Sensor Learn (With UH3) Tire Pressure Indicator Sensor Learn (With UH3)
* Control Module References Control Module References for RCDLR replacement, setup, and programming