P0573-BRAKE SWITCH 1 STUCK OFF

For a complete wiring diagram Refer to Section 8W

When Monitored:
With the ignition on, battery voltage greater than 10.4 volts, ambient temperature above -23 C.
Set Condition:
The PCM detects that the state of Brake Signal 1 does not change as expected.

Possible Causes

INTERMITTENT DTC

(B15) BRAKE SIGNAL 1 CIRCUIT SHORTED TO GROUND

(B16) BRAKE SIGNAL 2 CIRCUIT SHORTED TO VOLTAGE

(F202) FUSED IGNITION SWITCH OUTPUT (RUN-START) CIRCUIT OPEN OR HIGH RESISTANCE

(Z967) GROUND CIRCUIT OPEN OR HIGH RESISTANCE

(B15) BRAKE SIGNAL 1 CIRCUIT OPEN OR HIGH RESISTANCE

(B16) BRAKE SIGNAL 2 CIRCUIT OPEN OR HIGH RESISTANCE

STOP LAMP SWITCH

POWERTRAIN CONTROL MODULE (PCM)

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

Diagnostic Test

1. DTC IS ACTIVE

Turn the ignition on.
With the scan tool, monitor the states of Brake Signal 1 and Brake Signal 2 while pressing and releasing the brake pedal several times.

Do the Brake Signal states change appropriately as the pedal is pressed and released?

Yes

Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)

Go To 2

2. (B15) BRAKE SIGNAL 1 CIRCUIT

Turn the ignition off.
Disconnect the Powertrain Control Module (PCM) connector.
Using a 12 volt test light connected to 12 volts, check the (B15) Brake Signal 1 circuit in the Powertrain Control Module (PCM) harness connector while pressing and releasing the brake pedal several times.

Does the test light change from illuminated to not illuminated as the brake pedal is pressed and released?

Yes

Go to 3.

Go to 4

3. (B16) BRAKE SIGNAL 2 CIRCUIT

Turn the ignition on.
Using a 12 volt test light connected to ground, check the (B16) Brake Signal 2 circuit in the Powertrain Control Module (PCM) harness connector while pressing and releasing the brake pedal several times.

Does the test light change from illuminated to not illuminated as the brake pedal is pressed and released?

Yes

Go to 11

Go to 7

4. (Z967) GROUND CIRCUIT OPEN OR HIGH RESISTANCE

Turn the ignition off.
Disconnect the Stop Lamp Switch connector.
Using a 12 volt test light connected to 12 volts, check the (Z967) Ground circuit in the Stop Lamp Switch harness connector.

NOTE: The test light should be illuminated and bright. Compare the brightness to that of a direct connection to the battery.

Is the test light illuminated and bright?

Yes

Go to 5

Repair the (Z967) Ground circuit for an open circuit or high resistance.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

5. (B15) BRAKE SIGNAL 1 CIRCUIT SHORTED TO GROUND

Measure the resistance between ground and the (B15) Brake Signal 1 circuit in the Stop Lamp Switch harness connector.

Is the resistance above 100 ohms?

Yes

Go to 6

Repair the (B15) Brake Signal 1 circuit for a short to ground.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

6. (B15) BRAKE SIGNAL 1 CIRCUIT OPEN OR HIGH RESISTANCE

Measure the resistance of the (B15) Brake Signal 1 circuit between the Stop Lamp Switch harness connector and the Powertrain Control Module (PCM) harness connector.

Is the resistance below 5.0 ohms?

Yes

Go to 10

Repair the (B15) Brake Signal 1 circuit for an open circuit or high resistance.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

7. (F202) FUSED IGNITION SWITCH OUTPUT (RUN-START) CIRCUIT OPEN OR HIGH RESISTANCE

Turn the ignition off.
Disconnect the Stop Lamp Switch connector.
Turn the ignition on.
Using a 12 volt test light connected to ground, check the (F202) Fused Ignition Switch Output (Run-Start) circuit in the Stop Lamp Switch harness connector.

NOTE: The test light should be illuminated and bright. Compare the brightness to that of a direct connection to the battery.

Is the test light illuminated and bright?

Yes

Go to 8

Repair the (F202) Fused Ignition Switch Output (Run-Start) circuit for an open circuit or high resistance.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

8. (B16) BRAKE SIGNAL 2 CIRCUIT SHORTED TO VOLTAGE

Measure the voltage of the (B16) Brake Signal 2 circuit in the Stop Lamp Switch harness connector.

Is there any voltage present?

Yes

Repair the (B16) Brake Signal 2 circuit for a short to voltage.

Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

Go to 9

9. (B16) BRAKE SIGNAL 2 CIRCUIT OPEN OR HIGH RESISTANCE

Measure the resistance of the (B16) Brake Signal 2 circuit between the Stop Lamp Switch harness connector and the Powertrain Control Module (PCM) harness connector.

Is the resistance below 5.0 ohms?

Yes

Go to 10

Repair the (B16) Brake Signal 2 circuit for an open circuit or high resistance.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

10. STOP LAMP SWITCH

Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Stop Lamp Switch and the Powertrain Control Module (PCM).
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals.
Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.
Look for the data to change or for the DTC to reset during the wiggle test.
Refer to any Technical Service Bulletins that may apply.

Were any problems found?

Yes

Repair as necessary.

Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

Replace the Stop Lamp Switch in accordance with the Service Information.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

11. POWERTRAIN CONTROL MODULE (PCM)

Repair as necessary.

Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).

Replace and program the Powertrain Control Module (PCM) in accordance with the Service Information.
Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE).