Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Inspection Procedure
- CHECK DTC OUTPUTÂ
- Delete the DTC (See DTC CHECK / CLEARÂ
).
HINT:
After all DTCs are cleared, turn the engine switch on (IG) and depress the brake pedal. After 15 seconds have elapsed, check if the trouble occurs again.
- Check for DTCs again.
OK: No DTC is output.Â
NG: Go to step 2Â
OK : ENDÂ
- Delete the DTC (See DTC CHECK / CLEARÂ
).
- INSPECT POWER SOURCE CONTROL ECUÂ
- Measure the voltage according to the value(s) in the table below.
VoltageÂ
TERMINAL SPECIFIED CONDITION CHARTTerminal No. (Symbol) Condition Specified condition D44-39 (STSW) - Body ground Brake pedal depressed, Engine switch START 10 to 14 V HINT:
Voltage is output for 0.3 seconds after engine start.
NG: REPLACE POWER SOURCE CONTROL ECUÂ
OK: Go to next stepÂ
- Measure the voltage according to the value(s) in the table below.
- CHECK WIRE HARNESS (POWER SOURCE CONTROL ECU - ECM)Â
- Disconnect the D44 ECU connector.
- Disconnect the A55 ECM connector.
- Measure the resistance according to the value(s) in the table below.
ResistanceÂ
TERMINAL SPECIFIED CONDITION CHARTTerminal No. (Symbol) Specified Condition D44-39 (STSW) - A55-14 (STSW) Below 1 Ω D44-39 (STSW) - Body ground 10 kΩ or higher
NG: REPAIR OR REPLACE HARNESS OR CONNECTORÂ
OK: Go to next stepÂ
- CHECK POWER SOURCE CONTROL ECU OPERATIONÂ
- After replacing the power source control ECU with a normally functioning ECU, check that the engine can start.
OK: Engine can start normally.Â
NG:Â GO TO SFI SYSTEM
OK : END (POWER SOURCE CONTROL ECU DEFECTIVE)Â
- After replacing the power source control ECU with a normally functioning ECU, check that the engine can start.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.