DTC P0504, P0571, or P0703
Diagnostic Instructions
DTC Descriptors
DTC P0504: Brake Switch Circuits 1-2 Not
Plausible |
DTC P0571: Brake Switch Circuit 1 |
DTC P0703: Brake Switch Circuit 2 |
Circuit/System Description
The body control module (BCM) monitors the brake pedal position
sensor. When the brake pedal is applied, the BCM detects a
predetermined voltage signal. The BCM sends a serial data message
to the engine control module (ECM) indicating the status of the
stop lamps.
Conditions for Running the DTC
• |
Battery voltage must be
between 9-16 V. |
Conditions for Setting the DTC
The ECM receives an invalid brake pedal status serial data
message from the BCM.
Action Taken When the DTC Sets
P0504
• |
The cruise control system is
disabled. |
• |
The Stop/Start system is
disabled. |
P0571 or P0703
• |
The SVS will
illuminate. |
• |
The cruise control system is
disabled. |
• |
The Stop/Start system is
disabled. |
Conditions for Clearing the DTC
The condition responsible for setting the DTC no longer
exists.
Reference Information
Schematic Reference
Cruise Control Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Cruise Control Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
1. |
Ignition ON, verify that DTC
C0277 is not present in the BCM. |
2. |
Verify that DTC P0572 or P0573
is not present in the ECM. |
3. |
Observe the stop lamps while
applying and releasing the brake pedal. Verify the stop lamps
operate properly. |
4. |
Observe the ECM scan tool
Brake Pedal Switch parameter. The reading should change when the
brake pedal is pushed or released. |
⇒ |
If the not the specified value, refer to
Circuit/System Testing. |
Circuit/System Testing
1. |
Ignition OFF, disconnect the
X1 harness connector at the K20 Engine Control Module. |
2. |
Connect a test lamp between
the signal circuit harness connector terminal listed below and
ground: |
3. |
Ignition ON, verify the test
lamp turns ON and OFF when pressing and releasing the brake
pedal. |
⇒ |
If the test lamp is always ON, test the signal
circuit for a short to voltage. If the circuit tests normal,
replace the K9 Body Control Module. |
⇒ |
If the test lamp is always OFF, test the signal
circuit for a short to ground or an open/high resistance. If the
circuit tests normal, replace the K9 Body Control Module. |
4. |
If all circuits test normal,
replace the K20 Engine Control Module. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
Control Module References for BCM or ECM replacement,
programming and setup
|