This bulletin is being issued to revise the Park Brake
Will Not Hold symptom chart. Step 13 of this chart has been revised.
Please use the following to replace the existing information in the Park Brake
sub-section of the Service Manual.
Park Brake Will Not Hold
Step
| Action
| Value(s)
| Yes
| No
|
1
| Did you perform the park brake diagnostic system check?
| --
|
Go to Step 2
| Go to A Sympton Diagnostic System Check
|
2
|
- Turn ON the ignition, with the engine OFF
- Attempt to set the park brake.
Does the BRAKE indicator illuminate?
| --
|
Go
to Step 3
| Go to Brake Indicator Inoperative
|
3
|
- Turn the ignition switch to OFF.
- Remove the PRK BRK fuse from the rear fuse block.
- Connect a DMM set to amps scale across the terminals of the removed
fuse.
- Connect a scan tool to the data link connector (DLC) and turn
the ignition switch to ON.
- Establish communication with the rear integration module (RIM).
- Under special functions menu, select output control.
- With a scan tool, command the park brake relay A (park brake release
relay) ON and OFF.
Does the current through the DMM change from high to low as the relay
cycles?
| --
|
Go to Step 4
|
Go to Step 11
|
4
| With a scan tool, command the park brake relay
B (park brake ratchet relay) ON and OFF.
Does the current through the DMM change from high to low as the relay
cycles?
| --
|
Go to Step 14
|
Go to Step 5
|
5
|
- Reinstall PRK/BRK fuse.
- Disconnect the park brake release solenoid connector.
- Turn the ignition switch to ON.
- With a scan tool establish communication with the rear integration
module (RIM).
- Under special functions menu, select output control.
- Measure the voltage from the park brake relay A switch side control
circuit to a good ground at the park brake release solenoid connector.
- With a scan tool, command park brake relay A (park brake ratchet
relay) ON and OFF.
Does the voltage measure from 0 to the specified value on command?
| Battery Positive
Voltage (B+)
|
Go to Step 11
|
Go to Step 6
|
6
|
- Remove park brake relay A from the rear fuse block.
- With a DMM connected to battery positive voltage (B+), probe the
park brake relay A control circuit.
- With a scan tool, command the park brake relay A ON and OFF.
Does the voltage measure from 0 to the specified value on command?
| Battery Positive
Voltage (B+)
|
Go to Step 8
|
Go to Step 7
|
7
| Test the Park Brake Relay
A control circuit for a short to ground.
Did you find and correct the condition?
| --
|
Go
to Step 16
|
Go to Step 14
|
8
|
- Turn the ignition switch to OFF.
- Install a known good relay in place of park brake relay A.
- Turn the ignition switch to ON.
- Connect a DMM from the park brake relay A switch side control
circuit to a good ground, at the park brake release solenoid.
- With a scan tool as in Step 4, command park brake relay A ON and
OFF.
Does the voltage measure from 0 to the specified value on command?
| Battery Positive
Voltage (B+)
|
Go to Step 10
|
Go to Step 9
|
9
| Repair short to
battery positive voltage (B+) in the Park Brake Relay A switch side control
Circuit. Refer to Wiring Repairs in Wiring Systems
Did you complete the repair?
| --
|
Go to Step 16
| --
|
10
|
- Inspect for poor connections at the rear fuse block of the park
brake relay A .
- If OK, park brake relay A (already replaced in Step 8) is faulty.
Is the replacement complete?
| --
|
Go to Step 16
| --
|
11
|
- Using the scan tool, establish communication with the instrument
panel cluster (IPC).
- From the data inputs menu, select park brake input.
- Momentarily connect a fused jumper from the instrument cluster
park brake input circuit at the park brake release solenoid to a good ground,
then disconnect the jumper.
Does the cluster park brake input parameter, change state as the jumper
is connected, then removed?
| --
|
Go to Step 13
|
Go to Step 12
|
12
| Test the Park Brake Input circuit for a short to ground.
Did you find and correct the condition?
| --
|
Go
to Step 16
|
Go to Step 13
|
13
| Inspect for poor connections at the harness connector of the park brake
release solenoid connector.
Did you find and correct the condition?
| --
|
Go
to Step 16
|
Go to Step 15
|
14
|
- Check rear integration module (RIM) connector C2 for poor terminal
contact.
- If OK, replace RIM. Refer to Rear Integration Module Replacement
in Body Control System.
Did you complete the replacement?
| --
|
Go to Step 16
| --
|
15
| Replace the park brake release solenoid. Refer to Park Brake Pedal Replacement.
Did you complete the replacement?
| --
|
Go to Step 16
| --
|
16
| Operate the system in order to verify the repair.
Did you find and correct the condition?
| --
| System OK
|
Go
to Step 3
|
