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.
1991 Acura Legend Base, AutomaticFACTORY OEM SERVICE PROCEDURE
Manual Transmission Neutral Switch
- Connect PGM-FI test harness between ECU and ECU connectors. Turn ignition on. Place transmission in Neutral, and measure voltage between ECU terminal B7 (positive) and A26 (negative). If voltage is not present, go to step 3).
- If voltage exists, disconnect manual transmission neutral switch 2-wire connector located on side of transmission. Connect White wire terminal to Black wire terminal. If voltage is not present, replace neutral switch. If voltage is present, repair open in White wire between ECU terminal B7 and neutral switch.
- Shift transmission into gear. If about 10 volts is present, manual transmission neutral switch is okay. If battery voltage is not present, disconnect PGM-FI test harness connector "B" from main wire harness only; DO NOT disconnect from ECU. If 10 volts is not present, substitute a known good ECU and recheck.
- If about 10 volts is present, reconnect connector "B", and disconnect 2-wire connector on manual transmission neutral switch. If battery voltage is present, replace switch. If battery voltage is not present, repair short in White wire between ECU and manual transmission neutral switch.
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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