The body control module (BCM) sends a serial data message to the instrument panel cluster (IPC) requesting low tire pressure indicator illumination.

Important: It is Recommend that Component Testing is performed before Circuit Testing when diagnosing.

1. With the scan tool, select instrument panel special functions Lamp Test. Command the instrument panel warning lamps ON.

⇒	If the tire pressure monitor (TPM) warning lamp does not turn on, replace the IPC.

2. With the TPM special tool, transmit simulated tire pressures to the BCM. Observe the tire pressures in the scan tool data display.

⇒	If the TPM simulated tire pressure is not within ±4 psi of the scan tool reading, replace the BCM.

1. Inspect the tires for proper inflation pressure.

⇒	Inflate tires to the proper pressure. Refer to Vehicle Certification, Tire Placard, Anti-Theft, and Service Parts ID Label .

2. Using the TPM special tool to observe the tire pressure of the suspected faulty sensor. With a known accurate hand held tire pressure gauge, deflate the suspect tire pressure to 22 psi and compare the psi reading to the display on the TPM special tool.

⇒	If the tire pressure warning indicator illuminates, than the system is OK.

⇒	If the TPM special tool displays a difference of 4 psi more or greater than actual tire pressure, replace the suspect tire pressure sensor.

⇒	If actual and displayed tire pressure readings are normal, go to Circuit/System Testing.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.