Transmission Control System

P1520 - Stop Light Switch Circuit Malfunction

CIRCUIT DESCRIPTION

DTC Detecting Condition:

The purpose of this circuit is to prevent the engine from stalling, while driving in lock-up condition, when brakes are suddenly applied.

When the brake pedal is operated, this switch sends a signal to ECM. Then the ECM cancels operation of the lock-up clutch while braking is in progress.

Wiring Diagram:

Step 1:

Step 1(Continued) - 3:

INSPECTION PROCEDURE

HINT: Read freeze frame data using hand-held tester or OBDII scan tool. Because freeze frame records the engine conditions when the malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc. at the time of the malfunction.

CHECK FOR INTERMITTENT PROBLEMS

hand-held tester only:
By putting the vehicle's ECM in the check mode, 1 trip detection logic is possible instead of 2 trip detection logic and sensitivity to detect open circuits is increased. This makes it easier to detect intermittent problems.

1. Clear the DTC (See step 2).
2. Set the check mode (See step 3).
3. Perform a simulation test.
4. Check the connector and terminal.
5. Handle the connector.