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.
1994 Lexus LS 400FACTORY OEM SERVICE PROCEDURE
Momentary Interruption Test
If Code 13, 22, 24, 41 or 47 is stored in ECM memory during diagnosis and no trouble can be found with these circuits, perform MOMENTARY INTERRUPTION TEST.
- Clear codes from ECM memory. See CLEARING CODES. With ignition off, connect a jumper wire between terminals E1 and TE2 of DLCs No. 1 or 2. See Figure.
- Start engine. Ensure MIL goes out. Pull lightly on wires, and apply vibration to connectors and relays associated with diagnostic code that is set.
- If MIL illuminates during this test, a fault is in indicated connector or location in wiring harness. Repair as necessary.
- Clear diagnostic codes. Start engine. If MIL does not go out, check thoroughly for faulty connections. Perform MOMENTARY INTERRUPTION TEST again. If MIL still will not go out, check and replace ECM as necessary. See COMPUTERIZED ENGINE CONTROLS in SYSTEM/COMPONENT TESTS article in the ENGINE PERFORMANCE section.
NOTE:
Electronically Controlled Transaxle/Transmission (ECT) uses same ECM as EFI system.
Factory Service Tools
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.