DTC P0504 Brake Switch "A" / "B" Correlation: Description
In addition to turning on the stop lights, the stop light switch signals are used for a variety of engine, transmission and suspension functions. The stop light switch is designed with 2 complementary signal outputs, STP and ST1-. The ECM analyzes these signal outputs to detect malfunctions in the stop light switch.
DTC DETECTION CONDITION CHART
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P0504 | Conditions (a), (b) and (c) continue for 0.5 sec. or more:
|
|
HINT:
Normal condition is as shown in the table below. The signals can be read using the intelligent tester.
NORMAL CONDITION CHART
| Signal | Brake Pedal Released | In Transition | Brake Pedal Depressed |
|---|---|---|---|
| STP | OFF | ON | ON |
| ST1- | ON | ON | OFF |