P0504

DTC P0504 BRAKE SWITCH "A"/"B" CORRELATION

CIRCUIT DESCRIPTION

DTC Detection Condition:

In addition to turning on the stop lamps, the stop lamp switch signals are used for a variety of engine, transmission and suspension functions. The stop lamp switch is designed with two complementary signal outputs, STP and ST1-. The ECM analyzes these signal outputs to detect malfunctions in the stop lamp switch.

HINT: Normal condition is as shown in the table. The signals can be read using the hand-held tester.

Wiring Diagram:

Step 1 - 3:

Step 4:

INSPECTION PROCEDURE

CHECK FOR INTERMITTENT PROBLEMS

HINT: Inspect the vehicle's ECM using check mode. Intermittent problems are easier to detect when the hand-held tester is in check mode. In check mode, the hand-held tester uses 1 trip detection logic, which has a higher sensitivity to malfunctions than normal mode (default), which uses 2 trip detection logic.

a. Clear the DTCs.
b. Set the check mode.
c. Perform a simulation test.
d. Check the connector and terminal.
e. Wiggle the harness and the connector.