Test Description
The numbers below refer to the step numbers on the diagnostic table.
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Tests the park brake switch signal circuit. An open in the park brake switch of the park brake signal circuit will prevent release of the park brake and illumination of the red Brake warning indicator.
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Listen for an audible click when the park brake relay A operates. Command both the ON and OFF states. Repeat the commands as necessary.
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Listen for an audible click when the park brake relay B operates. Command both the ON and OFF states. Repeat the commands as necessary.
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Verifies that the BCM is providing ground to the park brake relay A.
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Verifies that the BCM is providing ground to the park brake relay B.
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Tests for voltage at the switch side of the park brake relay A. The PRK BRK fuse supplies power to the switch side of the park brake relay A.
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Tests for voltage at the switch side of the park brake relay B. The PRK BRK fuse supplies power to the switch side of the park brake relay B.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Park Brake System Schematics | |||
1 | Did you perform the Diagnostic System Check-Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
Did the red Brake warning indicator remain illuminated? | Go to Step 3 | Go to Brake Warning Indicator Inoperative in Hydraulic Brakes | |
Does the park brake relay A turn ON and OFF with each command? | Go to Step 4 | Go to Step 5 | |
With a scan tool, command the park brake relay B ON and OFF. Does the park brake relay B turn ON and OFF with each command? | Go to Step 9 | Go to Step 6 | |
5 |
Does the test lamp illuminate? | Go to Step 7 | Go to Step 17 |
6 |
Does the test lamp illuminate? | Go to Step 8 | Go to Step 17 |
Does the test lamp turn ON and OFF with each command? | Go to Step 24 | Go to Step 15 | |
Does the test lamp turn ON and OFF with each command? | Go to Step 25 | Go to Step 16 | |
Probe the switch side battery positive voltage circuit of the park brake relay A with a test lamp that is connected to a good ground. Does the test lamp illuminate? | Go to Step 10 | Go to Step 17 | |
10 | Connect a 3-amp fused jumper between the supply voltage circuit of the park brake relay A and the switch side battery positive voltage circuit of the park brake relay A. Does the park brake release? | Go to Step 24 | Go to Step 11 |
11 | Test the supply voltage circuit of the park brake relay A for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 28 | Go to Step 12 |
Probe the switch side battery positive voltage circuit of the park brake relay B with a test lamp that is connected to a good ground. Does the test lamp illuminate? | Go to Step 13 | Go to Step 17 | |
13 | Connect a 3-amp fused jumper between the supply voltage circuit of the park brake relay B and the switch side battery positive voltage circuit of the park brake relay B. Does the park brake release? | Go to Step 25 | Go to Step 14 |
14 | Test the supply voltage circuit of the park brake relay B for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 28 | Go to Step 18 |
15 | Test the control circuit of the park brake relay A for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 28 | Go to Step 19 |
16 | Test the control circuit of the park brake relay B for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 28 | Go to Step 19 |
17 | Inspect for poor connections at the harness connector of the fuse block underhood. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 28 | Go to Step 23 |
18 | Inspect for poor connections at the harness connector of the park brake release solenoid. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 28 | Go to Step 20 |
19 | Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 28 | Go to Step 27 |
20 | Inspect the park brake system for proper operation. Refer to Park Brake System Diagnosis . Did you find and correct the condition? | Go to Step 28 | Go to Step 21 |
21 | Inspect the disc brake system for proper operation. Refer to Disc Brake System Diagnosis in Hydraulic Brakes. Did you find and correct the condition? | Go to Step 28 | Go to Step 22 |
22 | Inspect the hydraulic brake system for proper operation. Refer to Hydraulic Brake System Diagnosis in Hydraulic Brakes. Did you find and correct the condition? | Go to Step 28 | Go to Step 26 |
23 | Replace the fuse block underhood. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems. Did you complete the replacement? | Go to Step 28 | -- |
24 | Replace the park brake relay A. Did you complete the replacement? | Go to Step 28 | -- |
25 | Replace the park brake relay B. Did you complete the replacement? | Go to Step 28 | -- |
26 | Replace the park brake release solenoid. Refer to Park Brake Release Solenoid Replacement . Did you complete the replacement? | Go to Step 28 | -- |
27 | Replace the body control module (BCM). Refer to Body Control Module Replacement in Computer/Integrating Systems. Did you complete the replacement? | Go to Step 28 | -- |
28 | Operate the system in order to verify the repair. Did you correct the condition? | Go to Step 2 | System OK |
