B2278

3MZ-FE STARTING: SMART KEY SYSTEM: B2278: Power Switch Circuit Malfunction

DTC B2278 - Power Switch Circuit Malfunction

DESCRIPTION

This DTC is output when 1) a malfunction is detected between the main body ECU (instrument panel junction block) and the power switch; or 2) either of the switches inside the power switch is malfunctioning.
HINT: When the main body ECU (instrument panel junction block) is replaced with a new one and the negative (-) battery terminal is connected, the power source mode becomes the IG-ON mode. When the battery is removed and reinstalled, the power source mode that was selected when the battery was removed is restored.

After the main body ECU (instrument panel junction block) is replaced, perform the registration procedures for the engine immobiliser system. Engine Immobiliser System






WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. READ VALUE USING TECHSTREAM (START SWITCH)
(a) Connect Techstream to the DLC3.
(b) Check the DATA LIST for proper functioning of the start switch.
HINT: When using Techstream with the power switch off, turn on and off any of the door courtesy light switches repeatedly at 1.5 second intervals or less until communication between the tester and vehicle starts.

Main Body:





OK:
ON (power switch is pushed) and OFF (power switch is not pushed) appear on the screen.
NG -- INSPECT POWER SWITCH
OK -- REPLACE MAIN BODY ECU (INSTRUMENT PANEL JUNCTION BLOCK)
2. INSPECT POWER SWITCH
(a) Remove the power switch.





(b) Disconnect the switch connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:





HINT: This switch is a momentary type switch.

NG -- REPLACE POWER SWITCH
OK -- Continue to next step.
3. CHECK HARNESS AND CONNECTOR (POWER SWITCH - MAIN BODY ECU AND BODY GROUND)
(a) Disconnect the D8 ECU connector.





(b) Disconnect the D25 switch connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE MAIN BODY ECU (INSTRUMENT PANEL JUNCTION BLOCK)