Diagnostic System Check

CIRCUIT DESCRIPTION
The Tire Pressure Monitor (TPM) Diagnostic System Check is an organized approach to identify problems associated with the TPM system. This check must be the starting point for any TPM complaint, and will direct you to the next logical step in diagnosing the complaint. The TPM uses the same receiver as the Remote Function Actuation (RFA) system. Therefore, when a TPM malfunction occurs, all diagnostic information (DTCs, input data, etc.) must be accessed through the RFA system.

DIAGNOSTIC AIDS
- The following conditions may result in an intermittent operation of the TPM system with no DTC stored:
- Any condition which results in the interruption of power to the receiver
- Over or underinflated tires
- Out-of-range battery or ignition voltage

Specification
Normal battery or ignition voltage:
9.0 - 16.0 V

- A loose or damaged ground(s)
- An open or shorted serial data line
- An intermittent failure in the electronic system may be very difficult to detect and to accurately diagnose. The TPM tests for different malfunctions under different vehicle conditions. For this reason, a thorough test drive is often needed in order to repeat a fault condition. If the system malfunction is not repeated during the test drive, a good description of the complaint may be very useful in locating an intermittent malfunction.
Faulty electrical connections or wiring causes most intermitting problems. When an intermitting condition is suspected, check the suspected circuits for the following conditions:
- Poor mating of connector halves or backed out terminals
- Improperly formed or damaged terminals
- Wire chafing
- Poor wire to terminal connections
- Dirty or corroded terminals
- Damage to connector bodies
- When a TPM system malfunction is corrected, clear the receiver's diagnostic memory before road testing the vehicle in order to avoid reading the original DTC stored in the memory.

TEST DESCRIPTION








A Diagnostic System Check - Tire Pressure Monitoring

The numbers below refer to the step numbers on the diagnostic table:
1. This test determines if communications can be established with the RFA system.
2. This test checks for communication DTCs stored in the RFA system (communication DTCs begin with the letter U). Communication DTCs must be diagnosed and corrected first before diagnosing any other DTCs.
3. This test checks for any TPM system DTCs stored in the receiver's memory.
4. This test checks for any RFA system DTCs stored in the receiver's memory. Some DTCs that are associated with the RFA system may cause a TPM system malfunction. Always diagnosis any RFA DTCs that are stored.
5. This test checks the IPC for any TPM system warning messages.
6. This test determines if communications can be established with other subsystems connected to the same serial data line.
7. This test checks the receiver's power circuit. If the test light does not go ON, there is an open in CKT 540.
8. This test checks the receiver's ground circuit. If the test light does not go ON, there is an open in CKT 851.
9. This test determines if there is an open in the serial data line between the receiver and the DLC terminal (CKT 1045).