Diagnostic Instructions
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 lift gate module (LGM) 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 40 km/h (25 mph) or greater, the LGM 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 LGM 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. |
| • | If equipped, the driver information center (DIC) displays the suspect tire pressure as dashes. |
| • | If equipped, the DIC 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 1 ignition cycle occurs. |
| • | The LGM 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 to
Tire Pressure Indicator Sensor Replacement. |
| • | 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 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 Sensor Learn. |
Reference Information
Description and Operation
Tire Pressure Monitor Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for Scan Tool Information
Special Tools
J-46079
Tire Pressure Monitor Diagnostic Tool
Circuit/System Verification
- Using the
J-46079
, activate each tire pressure sensor and record each sensors transmission data and physical location. Verify
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. |
- 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.
- Enable the TPM learn mode. Use the
J-46079
in simulate mode to learn 4 simulated sensor transmissions into the LGM. 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 LGM. |
- 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 after completing the diagnostic procedure.
