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Home >> Lexus >> 1999 >> SC 400 V8-4.0L (1UZ-FE) >> Repair and Diagnosis >> Cruise Control >> Brake Switch (Cruise Control) >> Testing and Inspection
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Brake Switch (Cruise Control): Testing and Inspection

CIRCUIT DESCRIPTION

When the brake pedal is depressed, the stop light switch sends a signal to the ECM. When the ECM receives this signal, it cancels the cruise control.

A fail-safe function is provided so that the cancel functions normally, even if there is a malfunction in the stop light signal circuit.

The cancel conditions are: Battery positive voltage at terminal STP-

When the brake is on, battery positive voltage normally applies through the STOP fuse and stop light switch to terminal STP- of the ECM, and the ECM turns the cruise control off.

If the harness connected to terminal STP- has an open circuit, terminal STP- will have battery positive voltage and the cruise control will be turned off.




DETECTING CONDITIONS




WIRING DIAGRAM

Step 1:




Step 2:




Step 3:




INSPECTION PROCEDURE

HINT: In case of using the LEXUS hand-held tester, start the inspection from step 1 and in case of not using the LEXUS hand-held tester. start from step 2.
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