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
Fuel Injector Circuit
- Turn ignition off. Remove cover from below right side of instrument panel for access to ECM. Turn ignition on. At ECM connector E9, measure voltage between chassis ground and terminals No. 7, 8, 9 and 10 (Blue, Red, Black/Yellow and Yellow wires). To identify ECM connectors and terminals, see Figure.
- If battery voltage is measured at all terminals, go to next step. If battery voltage is not measured at all terminals, check fusible link AM2 (30-amp). See COMPONENT LOCATIONS under INTRODUCTION. If fusible link AM2 is open (blown), check for shorted wiring harness. If fusible link AM2 is okay, repair circuit between ECM and battery.
- Check ECM ground circuits. See ECM GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS. If ground circuits are okay, measure injector resistance and volume. See FUEL INJECTOR RESISTANCE and FUEL INJECTOR VOLUME . If resistance and volume are as specified, replace ECM.
Factory Service Tools
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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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