For 1990-2009 cars

### 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.

### Circuit/System Description

The tire pressure monitor receiver receives a radio frequency (RF) transmission from each tire pressure sensor. Each sensor RF transmission contains its own unique identification (ID) code that must be learned into the tire pressure monitor receiver memory. Once all 4 IDs have been learned and vehicle speed is greater than 32 km/h (20 mph), the tire pressure monitor receiver continuously compares IDs in received transmission to its learned IDs to determine if all 4 sensors are present. If the tire pressure monitor receiver detects a low tire pressure condition or a malfunction in the system, it will send a serial data message to the instrument panel cluster (IPC) requesting tire pressure monitor indicator illumination.

### 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 specifications. Refer to Vehicle Certification, Tire Placard, Anti-Theft, and Service Parts ID 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 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.

• | Occasionally sensor transmissions are not received by the tire pressure indicator receiver 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.

• | Occasionally, stray sensor transmissions can be received from other vehicles.

### Reference Information

#### Schematic Reference

Tire Pressure Monitoring System Schematics

#### Description and Operation

Tire Pressure Monitor Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

#### Special Tools

J-46079 Tire Pressure Monitor Diagnostic Tool

### Circuit/System Verification

Note: Low tire pressure in one or more tires is indicated by a continuously illuminated tire pressure monitor indicator icon after the IPC bulb check is completed. If equipped with a DIC, a check tire pressure type message will also be displayed. It is not necessary to perform the Learn procedure for a low tire pressure condition.

When a TPM DTC is set, the tire pressure monitor indicator icon will flash for 1 minute after the IPC bulb check is completed and then remains illuminated. If equipped with a DIC, a service tire monitor type message will also be displayed.

1. Verify all tires are inflated to the proper pressure ± 10%. Refer to Vehicle Certification, Tire Placard, Anti-Theft, and Service Parts ID Label.

⇒ | If not within the specified range, adjust all tire pressures to specification and drive the vehicle over 32 km/h (20 mph) for greater than 10 minutes. The tire pressure monitor indicator icon should turn OFF.

2. With a scan tool, verify that the TP Sensor Pressure data parameters 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 and perform the Tire Pressure Sensor Learn procedure.

3. Ignition ON, with the scan tool, command the instrument panel cluster (IPC) tire pressure monitor icon ON and OFF. Verify that the tire pressure monitor indicator icon turns ON and OFF when commanded.

⇒ | If the tire pressure monitor icon does not turn ON and OFF, replace the IPC.

4. Perform the Tire Pressure Sensor Learn procedure. With a scan tool, verify that the TP Sensors data parameters display the following:

• | ID number recorded for each sensor

• | Valid ID Status for each sensor

• | Accurate tire pressure ± 27.6 kPa (4 psi) for each tire

• | Normal Battery status for each sensor

⇒ | If any of the parameters are not as specified, replace the appropriate tire pressure sensor and perform the Tire Pressure Sensor Learn procedure.

5. Perform the Reset ECU and replace the tire pressure indicator receiver.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Tire Pressure Indicator Sensor Replacement

• | Tire Pressure Sensor Learn

• | Control Module References for IPC or tire pressure indicator receiver replacement, setup, and programming