1991 Acura Legend Base, AutomaticFACTORY OEM SERVICE PROCEDURE

Code 10: Air Temperature (Ta) Sensor

NOTE: For wiring diagrams, see WIRING DIAGRAMS article in the ENGINE PERFORMANCE Section. For vacuum diagrams, see VACUUM DIAGRAMS article in the ENGINE PERFORMANCE Section.
  1. Turn ignition off. Remove ACG fuse in underdash fuse box for 10 seconds to reset ECU. Start engine, and connect jumper wire to diagnostic connector. Observe CHECK ENGINE light. If light is not flashing, problem is intermittent. Check for poor and loose connections at TA sensor and connector C355 at right shock tower. Test drive, and check again.
  2. If CHECK ENGINE light flashes Code 10, disconnect 2-pin sensor connector. If resistance of TA sensor is not 400-4000 ohms, replace TA sensor. If resistance is okay, measure voltage between Red/Yellow terminal and ground.
  3. If about 5 volts are not present, repair open or short in Red/Yellow wire between ECU terminal D15 and TA sensor. If wire is okay, substitute a known good ECU. If proper voltage is now present, replace ECU. If about 5 volts are present, measure voltage between Red/Yellow (positive) and Green/White (negative) wire terminals.
  4. If about 5 volts are not present, repair open in Green/White wire between ECU terminal D22 and TA sensor. If about 5 volts are present, substitute a known good ECU, and recheck. If condition goes away, replace ECU.
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:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.