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 TCM (POWER SOURCE, GROUND)
- Disconnect the A12 and E5 TCM connectors.
- Turn the engine switch on (IG).
- Measure the voltage of the wire harness side connectors.
Standard voltage
TESTER CONNECTION SPECIFIED CONDITION CHARTTester Connection Switch Condition Specified Condition A12-6 (+B) - E5-7 (E1) Engine switch on (IG) 11 to 14 V - Turn the engine switch off.
- Measure the resistance of the wire harness side connector.
Standard resistance
TESTER CONNECTION SPECIFIED CONDITION CHARTTester Connection Condition Specified Condition E5-7 (E1) - Body ground Always Below 1 Ω
NG: CHECK HARNESS AND CONNECTOR (TCM EFI MAIN NO. 2 RELAY, GROUND)
OK: GO TO ECM POWER SOURCE CIRCUIT (ENGINE CONTROL SYSTEM / SFI SYSTEM) (See ECM POWER SOURCE CIRCUIT )
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.
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.
Rather have a pro handle this?
A certified mobile mechanic comes to your home or office. They bring the tools, you stay comfortable. No tow truck, no waiting room, no surprises.
No obligation. See pricing before you book.