B2278

2AZ-FXE 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 and the power switch; or 2) either of the switches inside the power switch is malfunctioning.
HINT: When the main body ECU 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 is replaced, perform the registration procedures for the engine immobiliser system Programming and Relearning.






WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. READ VALUE USING TECHSTREAM
(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 on (IG)) and "OFF" (Power switch off) appear on the screen.
NG -- INSPECT POWER SWITCH
OK -- Continue to next step.
2. CHECK POWER SWITCH CONDITION
(a) Check the power source mode change.
(1) When the key is inside the vehicle and the shift lever is in the P position, check that pressing the power switch causes the power source mode to change as follows:
OK:
off -> on (ACC) -> on (IG) -> off
HINT:
- If power mode does not change to ON (IG and ACC) Power Source Mode Does Not Change To ON (IG and ACC).
- If power mode does not change to ON (IG) Power Source Mode Does Not Change To ON (IG).
- If power mode does not change to ON (ACC) Power Source Mode Does Not Change To ON (ACC).

NG -- GO TO OTHER PROBLEM
OK -- END
3. 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.
4. CHECK WIRE HARNESS (POWER SWITCH - MAIN BODY ECU AND BODY GROUND)
(a) Disconnect the E7 ECU connector.




(b) Disconnect the E52 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