Pinpoint Tests AA: The Tire Pressure Monitoring System (TPMS) Warning Indicator Is Never/Always On

Instrumentation, Message Center and Warning Chimes

Pinpoint Test AA: The Tire Pressure Monitoring System (TPMS) Warning Indicator Is Never/Always On

Normal Operation

Each road tire is equipped with a tire pressure sensor fastened to the inside rim of the wheel. The pressure sensor is covered by the tire and is not visible unless the tire is removed. The tire-mounted pressure sensors transmit signals to the DDM by using the valve stem as an antenna. These signals are sent approximately every 60 seconds when the vehicle speed exceeds 32 km/h (20 mph). The DDM compares each tire pressure sensor signal against low and high pressure limits. If the DDM determines that the tire pressure has exceeded the limit, the DDM communicates over the Medium Speed Controller Area Network (MS-CAN) to the IC, which then illuminates the Tire Pressure Monitoring System (TPMS) warning indicator. If a TPMS fault condition exists, the DDM sends a message to the IC to flash the TPMS warning indicator.

This pinpoint test is intended to diagnose the following:

- TPMS concern
- DDM
- IC



PINPOINT TEST AA: THE TPMS WARNING INDICATOR IS NEVER/ALWAYS ON

NOTE: Verify that the tire pressure is correct for all tires before continuing with diagnostics.

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AA1 CARRY OUT THE IC INDICATOR LAMP CONTROL ACTIVE COMMAND USING THE SCAN TOOL


- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IC DataLogger.
- Select the TPMS warning indicator (TPM_IND) active command. Command the TPMS warning indicator on and off. Observe the TPMS warning indicator.
- Does the TPMS warning indicator illuminate when commanded on and turn off when commanded off?

Yes
GO to AA2.

No
INSTALL a new IC. REFER to Instrument Cluster (IC) Instrument Cluster (IC). TEST the system for normal operation.

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AA2 RETRIEVE THE RECORDED DTCs FROM THE IC SELF-TEST


- Check for recorded IC DTCs from the self-test.
- Is DTC U1900 recorded?

Yes
REPAIR all other DTCs first. CLEAR the DTCs. CYCLE the key OFF then ON and wait 10 seconds. REPEAT the self-test.

If DTC U1900 is still present, REFER to Information Bus to diagnose communication with the DDM.

No
GO to AA3.

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AA3 RETRIEVE THE RECORDED DTCs FROM THE DDM SELF-TEST


- Check for recorded DDM DTCs from the continuous and on-demand self-tests.
- Are any DTCs recorded?

Yes
REFER to Body Control Systems.

No
INSTALL a new DDM. TEST the system for normal operation.

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