P0573
P0573-BRAKE SWITCH 1 STUCK OFF
For a complete wiring diagram, refer to the Wiring Information.
Theory of Operation
The brake switch rationality checks both failure modes of the brake switch. The brake switch stuck on test checks for a high vehicle speed condition where the brake switch is unexpectedly depressed. The brake switch stuck off test checks for repeated vehicle stop maneuvers without the brake switch depressed.
- When Monitored:
When vehicle speed cycles from 0 kph to 48 kph (30 mph) at least 10 times.
- Set Condition:
When the Powertrain Control Module (PCM) recognizes Brake Switch No.1 is stuck in the high/off position. Two Trip Fault. Three good trips to turn off the MIL.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.
Diagnostic Test
1. ACTIVE DTC
1. Ignition on, engine not running.
2. With a scan tool, select View DTCs.
NOTE: It may be necessary to drive the vehicle to meet the conditions to set this DTC, try to repeat the conditions in which the fault originally set by reviewing the Freeze Frame data.
Is the DTC Active at this time?
Yes
- Go To 2
No
- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test.
2. STOP LAMP SWITCH
1. Turn the ignition off.
2. Disconnect the Stop Lamp Switch harness connector.
3. Measure the resistance between terminal 1 and terminal 4 at the Stop Lamp Switch.
4. Apply and release the Stop Lamp Switch while monitoring the Ohmmeter.
Does the resistance change from below 5.0 Ohms to an open circuit for the measurement taken?
Yes
- Go To 3
No
- Verify that there is good pin to terminal contact in the Switch and Powertrain Control Module harness connectors. If OK, replace the Stop Lamp Switch. Stop Lamp Switch - Removal.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
3. CHECK THE (B135) BRAKE SWITCH NO.1 SIGNAL CIRCUIT FOR AN OPEN
1. Disconnect the PCM C1 harness connector.
2. Measure the resistance of the (B135) Brake Switch No.1 Signal circuit between the Stop Lamp Switch harness connector and the appropriate terminal of the PCM C1 harness connector.
Is the resistance below 5.0 Ohms?
Yes
- Go To 4
No
- Repair the (B135) Brake Switch No.1 Signal circuit for an open.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
4. CHECK THE (B135) BRAKE SWITCH NO.1 SIGNAL CIRCUIT FOR A SHORT TO GROUND
1. Measure the resistance between ground and the (B135) Brake Switch No.1 Signal circuit at the Stop Lamp Switch harness connector.
Is the resistance above 10k Ohms?
Yes
- Go To 5
No
- Repair the (B135) Brake Switch No.1 Signal circuit for a short to ground.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
5. CHECK THE (A103) STOP LAMP SWITCH BATTERY FEED CIRCUIT FOR AN OPEN
1. Remove Fuse 25 (5A) from the Power Distribution Center (PDC).
2. Measure the resistance of the (A103) Stop Lamp Switch Battery Feed circuit from the PDC to the Stop Lamp Switch harness connector.
Is the resistance below 5.0 Ohms?
Yes
- Go To 6
No
- Repair the open in the (A103) Stop Lamp Switch Battery Feed circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
6. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Stop Lamp Switch and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the Switch and Powertrain Control Module harness connectors.
4. Perform any Technical Service Bulletins that may apply.
Were there any problems found?
Yes
- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Replace and program the Powertrain Control Module. .
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.