C0761

DTC C0751, C0756, C0761, or C0766

Diagnostic Instructions

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

DTC Descriptors
DTC C0751
- Reception Failure

DTC C0756
- Reception Failure

DTC C0761
- Reception Failure

DTC C0766
- Reception Failure

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 Drive mode. The tire pressure module receives and translates the data contained in the tire pressure sensor RF transmissions into sensor presence, sensor mode, and tire pressure. The tire pressure module receives vehicle speed information from the transmission control module (TCM). Once a vehicle speed signal of greater than 32km/h (20 mph) is received, the tire pressure module waits for the sensors to go into Drive mode. If the tire pressure is below or above the predetermined threshold specification or if there is a malfunction in the tire pressure monitor system, the tire pressure module will illuminate the low tire pressure indicator icon on the instrument panel cluster (IPC).

Diagnostic Aids

* If unsure about the condition, cycle the ignition and observe the tire pressure monitor indicator icon. If the tire pressure monitor indicator icon is continuously illuminated after the IPC bulb check is completed, a low tire pressure condition is present. Check the tires for damage or leaks and inflate to the tire placard specification. Refer to the placard specification label. If the tire pressure monitor indicator icon flashes for 1 minute after the IPC bulb check is completed and then remains illuminated, a tire pressure monitor system DTC is set. Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) to proceed with the proper diagnosis.
* Temperature can greatly effect tire pressures. Low tire pressure on a cold morning may cause the tire pressure monitor indicator icon to turn ON. The air pressure in the tire increases as the ambient temperature rises or as the tire warms up while the vehicle is driven. The pressure may increase enough to exceed the predetermined low pressure threshold which will turn OFF the tire pressure monitor indicator icon.
* 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 value 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 (Service and Repair).
* Occasionally sensor transmissions are not received by the tire pressure module 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 Monitor System Configuration (Programming and Relearning).

Conditions for Running the DTC

Vehicle speed is above 32 km/h (20 mph).

Conditions for Setting the DTC

A tire pressure monitor sensor transmitter is inoperative.

Action Taken When the DTC Sets

The instrument panel cluster (IPC) tire pressure indicator warning lamp icon flashes for 75 seconds.

Conditions for Clearing the DTC

* The conditions for setting the DTC are no longer present.
* The DTC can be cleared with the scan tool.

Reference Information
Schematic Reference

Tire Pressure Monitoring System Schematics ([1][2]Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Tire Pressure Indicator Receiver Scan Tool Information (Tire Pressure Indicator Receiver Scan Tool Information)
Special Tools

J-46079 Tire Pressure Monitor Diagnostic Tool

Circuit/System Verification

1. Using the J-46079 , activate each tire pressure sensor and record each sensor tire pressure reading. Check the tire pressures with a known accurate hand held tire pressure gauge. Verify that the pressure readings from the special tool do not differ more than 27.6 kPa (4 psi) from the actual tire pressure readings.

• If not within the specified range, replace the appropriate tire pressure sensor.

2. Using a scan tool, enable the TPM learn mode. Use the J-46079 in simulate mode to learn 4 simulated sensor transmissions into the tire pressure module. Observe tire pressures in the scan tool data display. Verify the simulated tire pressures do not differ more than +/-27.6 kPa (4 psi) of the scan tool reading.

• If not within the specified range, replace the tire pressure module.

Repair Instructions

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

* Tire Pressure Indicator Sensor Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for tire pressure module replacement, programming, and setup.