DTC B2278: Engine Switch Circuit Malfunction: Procedure
WARNING: This page is about a different car, the 2011 Toyota Avalon. However, it is still accessible from the selected car via links, so may be relevant.
- READ VALUE USING TECHSTREAM
- Connect Techstream to the DLC3.
- Turn the engine switch on (IG) and press Techstream main switch on.
- Read the Data List according to the displays on the tester.POWER SOURCE CONTROL
Tester Display Measurement Item/Range Normal Condition Diagnostic Note Start Switch1 Status of start switch 1 / ON or OFF ON: Engine switch ON (IG)
OFF: Engine switch OFF (IG)- Start Swtich2 Status of start switch 2/ ON or OFF ON: Engine switch ON (IG)
OFF: Engine switch OFF (IG)- OK
"ON" (engine switch on (IG)) appears on the screen
Result
Condition Proceed to NG C OK (When troubleshooting according to the PROBLEM SYMPTOM TABLE) B OK (When troubleshooting according to the DTC chart) A
B → PROCEED TO PROBLEM SYMPTOMS TABLE NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
C → See step 2
A → REPLACE POWER SOURCE CONTROL ECU
- INSPECT ENGINE SWITCH
- Disconnect the D21 switch connector.
- Measure the resistance according to the value(s) in the table below.
Resistance
Terminal No. (Symbol) Switch Condition Specified value D21-2 (SS2) - D21-5 (GND) Free 10 kΩ or higher Pushed (Hold) Below 1 Ω D21-7 (SS1) - D21-5 (GND) Free 10 kΩ or higher Pushed (Hold) Below 1 Ω
NG → REPLACE ENGINE SWITCH
OK: Go to next step
- CHECK WIRE HARNESS (ENGINE SWITCH - POWER SOURCE CONTROL ECU AND BODY GROUND)
- Disconnect the D44 ECU connector.
- Disconnect the D21 Switch connector.
- Measure the resistance of the wire harness side connectors.
Resistance
Terminal No. (Symbol) Specified Condition D21-7 (SS1) - D44-14 (SSW1) Below 1 Ω D21-2 (SS2) - D44-37 (SSW2) Below 1 Ω D21-5 (GND) - Body ground Below 1 Ω D21-7 (SS1) or D44-14 (SSW1) - Body ground 10 kΩ or higher D21-2 (SS2) or D44-37 (SSW2) - Body ground 10 kΩ or higher
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK → REPLACE ENGINE SWITCH