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 THAT MIL ILLUMINATESÂ
- Perform troubleshooting in accordance with the table below.
ResultÂ
RESULT REFERENCEMIL Condition Proceed to MIL remains ON A MIL does not illuminate B B: Go to step  5
A: Go to next stepÂ
- CHECK WHETHER MIL TURNS OFFÂ
- Connect the Techstream to the DLC3.
- Turn the ignition switch to ON.
- Turn the Techstream on.
- Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
- Check if any DTCs have been detected. Write down any DTCs.
ResultÂ
RESULT REFERENCEResult Proceed to No DTC detected A DTCs are detected B HINT:
Check for detected DTCs output from other ECUs which relate to the MIL.
B: REPAIR CIRCUITS INDICATED BY OUTPUT DTCSÂ (See DIAGNOSTIC TROUBLE CODE CHARTÂ )
A: Go to next stepÂ
- CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT IN WIRE HARNESS)Â
- Disconnect the ECM connector.
- Turn the ignition switch to ON.
- Check that the MIL does not illuminate.
OK:Â
MIL not illuminated .
- Reconnect the ECM connector.
NG: Go to step 4Â
OK: REPLACE ECMÂ (See ECMÂ )
- CHECK HARNESS AND CONNECTOR (COMBINATION METER - ECM)Â
- Disconnect the ECM connector.
- Disconnect the combination meter connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Short)Â
RESISTANCE REFERENCETester Connection Condition Specified Condition A37-24 (W) or E55-20 (EFI) - Body ground Always 10 kΩ or higher - Reconnect the ECM connector.
- Reconnect the combination meter connector.
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (COMBINATION METER - ECM)Â
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
OK: REPLACE COMBINATION METERÂ (See PROBLEM SYMPTOMS TABLE )
- CHECK THAT MIL IS ILLUMINATEDÂ
- Check if the MIL is illuminated when the ignition switch is turned to ON.
OK:Â
MIL should be illuminated .
NG: Go to step 6Â
OK: SYSTEM OKÂ
- Check if the MIL is illuminated when the ignition switch is turned to ON.
- CHECK THAT ENGINE STARTSÂ
- Turn the ignition switch to ON.
- Start the engine.
ResultÂ
RESULT REFERENCEResult Proceed to Engine starts A Engine does not start* B HINT:
*: The Techstream cannot communicate with the ECM.B: GO TO VC OUTPUT CIRCUITÂ (See VC OUTPUT CIRCUITÂ )
A: Go to next stepÂ
- CHECK HARNESS AND CONNECTOR (COMBINATION METER - ECM)Â
- Disconnect the ECM connector.
- Disconnect the combination meter connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open)Â
RESISTANCE REFERENCETester Connection Condition Specified Condition A37-24 (W) - E55-20 (EFI) Always Below 1 Ω - Reconnect the ECM connector.
- Reconnect the combination meter connector.
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (COMBINATION METER ECM)Â
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
OK: REPLACE COMBINATION METERÂ (See PROBLEM SYMPTOMS TABLE )
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.
