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Home › Acura › 1990 › Legend Base, 4D Sedan, Automatic › Repair and Diagnosis › Engine Performance › System › Engine Controls - Tests W/Codes › Code 30: A/T FI Signal "A"

Code 30: A/T FI Signal "A"

NOTE: For wiring diagrams, see WIRING DIAGRAMS article. For vacuum diagrams, see VACUUM DIAGRAMS article.
  1. Turn ignition off. Remove alternator sense fuse in under-hood relay box for 10 seconds to reset ECU. Test drive vehicle for several miles so that transmission upshifts and downshifts several times. After test drive, observe CHECK ENGINE and Red LED lights. If lights are not on, failure is intermittent.
  2. Check for poor or loose connections at connectors C315 and C404. If CHECK ENGINE light is on, and Red LED indicates Code 30, turn ignition off. Connect ECU test harness to ECU. Disconnect 22-pin connector from automatic transmission control unit. Check for continuity between D3 and ground.
  3. If continuity is present, repair short in Blue/Green wire between ECU terminal D3 an automatic transmission control unit. If continuity is not present, check for continuity on Blue/Green wire between D3 and 22-pin connector of automatic transmission control unit.
  4. If continuity does not exist, repair open in Blue/Green wire between D3 and automatic transmission control unit. If continuity exists, substitute a known good ECU. If system operates properly, replace original ECU.
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