Circuit Description
The electronic brake control module (EBCM) turns ON the tire pressure warning indicator by opening the tire pressure warning indicator control circuit. The tire pressure warning indicator is connected to the GAUGE fuse. This circuit has power when the ignition switch is in the ON or START positions. When the ignition switch is turned to the ON position, the EBCM turns ON the tire pressure warning indicator for 3-4 seconds for a bulb check. If the EBCM detects a malfunction, the tire pressure warning indicator will stay ON to warn the driver that the tire pressure warning system is disabled and needs service.
Diagnostic Aids
Thoroughly inspect the wiring and the connectors. An incomplete inspection of the wiring and the connectors may result in a misdiagnosis, causing a part replacement with the reappearance of the malfunction.
The following are possible causes of the malfunction:
| • | An open or high resistance in the stop lamp signal circuit |
| • | A short in the stop lamp signal circuit |
| • | An internal EBCM malfunction |
If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests the stop lamp signal circuit for an open, high resistance, or short to ground.
-
This step tests the stop lamp signal circuit for a short to voltage.
Step | Action | Values | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
Schematic Reference: Tire Pressure Monitoring System Schematics Connector End View Reference: Tire Pressure Monitoring System Connector End Views | ||||||||
1 | Did you perform a Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | ||||
2 | Does the tire pressure warning indicator flash ON for 0.5 seconds and OFF for 2.5 seconds? | -- | Go to Step 4 | Go to Step 3 | ||||
3 | Does the tire pressure warning indicator flash ON and OFF at 0.5 second intervals? | -- | Go to Step 5 | -- | ||||
4 | Reset and initialize the tire pressure warning system. Refer to Tire Pressure Monitor Procedure . Did you complete the procedure? | -- | Go to Step 11 | -- | ||||
5 | Depress the brake pedal and observe the stop lamps. Do the stop lamps illuminate? | -- | Go to Step 6 | Go to Stop Lamps Inoperative in Lighting Systems | ||||
6 |
Is the voltage within the specified value? | 10-14 V | Go to Step 7 | Go to Step 8 | ||||
7 | Measure the voltage of the stop lamp signal circuit at the EBCM connector, with brake pedal released. Refer to Circuit Testing in Wiring Systems. Is the voltage less than the specified value? | 1.5 V | Go to Step 10 | Go to Step 9 | ||||
Test the stop lamp signal circuit for the following conditions:
Refer to Connector Repairs and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 11 | -- | |||||
Test the stop lamp signal circuit for a short to voltage. Refer to Connector Repairs and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 11 | -- | |||||
10 | Replace the brake pressure modulator valve (BPMV). Refer to Brake Pressure Modulator Valve Assembly Replacement . Is the repair complete? | -- | Go to Step 11 | -- | ||||
11 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 2 | ||||
