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.
Terminals Of Ecu
- CHECK HEATER CONTROL
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
- Measure the voltage and resistance according to the value(s) in the table below.
Standard voltage:
TERMINALS VOLTAGE REFERENCETerminal No. (Symbols) Wiring Color Terminal Description Condition Specified Condition C40-2 (RDEF) - C40-5 (E) B - W-B Rear defogger signal Ignition switch ON, Rear defogger switch OFF 11 to 14 V Ignition switch ON, Rear defogger switch ON Below 1 V C40-3 (IG+) - C40-5 (E) Y - W-B Power source Ignition switch ON 11 to 14 V Ignition switch OFF Below 1 V Standard resistance:
TERMINALS RESISTANCE REFERENCETerminal No. (Symbols) Wiring Color Terminal Description Condition Specified Condition C40-5 (E) - Body ground W-B - Body ground Ground Always Below 1 Ω If the result is not as specified, there may be a malfunction in the wire harness.
- Measure the voltage and resistance according to the value(s) in the table below.
- CHECK MAIN BODY ECU
- Measure the voltage according to the value(s) in the table below.
Standard voltage:
TERMINALS VOLTAGE REFERENCETerminal No. (Symbols) Wiring Color Terminal Description Condition Specified Condition 2G-1 - Body ground W - Body ground Power source Always 11 to 14 V 2Q-12 - Body ground B - Body ground DEF Relay operation signal Ignition switch ON, Rear defogger switch OFF 11 to 14 V Ignition switch ON, Rear defogger switch ON Below 1 V 2F-2 - Body ground B - Body ground Defogger wire operation signal Ignition switch ON, Rear defogger switch OFF Below 1 V Ignition switch ON, Rear defogger switch ON 11 to 14 V If the result is not as specified, there may be a malfunction in the wire harness or main body ECU.
- Measure the voltage according to the value(s) in the table below.
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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.
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