INSPECTION PROCEDURE 1. INSPECT AIR SWITCHING VALVE ASSEMBLY
(b) Check the operation of the air switching valve assembly. (1) Check that air does not flow from port A to port B. Text in Illustration
NOTICE: Make sure the applied pressure is 30 kPa (0.3 kgf/cm2, 4.4 psi) or less. If the result is not as specified, replace the air switching valve assembly. (2) Apply battery voltage across terminals 1 and 5. Text in Illustration
NOTICE: When applying voltage, do not touch terminals 2, 3 or 4. (3) Check that air flows from port A to port B. If the result is not as specified, replace the air switching valve assembly. |
Toyota Tundra Service Manual > Sfi System: Brake Switch "A" / "B" Correlation (P0504)
DESCRIPTION The stop light switch is a duplex system that transmits two signals: STP and ST1-. These two signals are used by the ECM to monitor whether or not the brake system is working properly. If the signals, which indicate the brake pedal is being depressed and released, are detected simultaneo ...