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Home >> Acura >> 1990 >> Legend Base, 4D Sedan, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Code 6: Coolant (TW) Sensor
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Code 6: Coolant (TW) Sensor

NOTE: For wiring diagrams, see WIRING DIAGRAMS article. For vacuum diagrams, see VACUUM DIAGRAMS article.
  1. Turn ignition off. Disconnect alternator sense fuse in under-hood relay box for 10 seconds to reset ECU. Start engine and observe CHECK ENGINE and LED lights. If lights are off, problem is intermittent. Check for poor or loose connections at TW sensor, Red/White wire terminal at connectors C103 and C303, and Green/White wire terminal at connectors C305 and C102 at right shock tower. Test drive and check again.
  2. If CHECK ENGINE light is on and LED indicates Code 6, turn engine off. Connect ECU test harness between ECU and ECU connectors. Warm engine to normal operating temperature (cooling fan on). Turn ignition off. Disconnect ECU connector "C" from ECU side only.
  3. Measure resistance between ECU terminals C6 and C14. See Figure . If reading is 200-400 ohms, go to step 4). If not, check for open circuit in Green/White wire between ECU terminal C14 and TW sensor, or open in Red White wire between ECU terminal C6 and TW sensor. If wires are okay, replace TW sensor.
  4. Reconnect ECU connector "C" to ECU side and disconnect connector "C" from main wire harness side. Turn ignition on. Measure voltage between ECU terminals C6 (positive) and C14 (negative). If about 5 volts is present, go to step 5). If not, substitute a known good ECU and recheck. If specified voltage is now available, replace original ECU.
  5. Turn ignition off. Reconnect ECU connector "C" to main wire harness. Turn ignition on. Measure voltage between ECU terminals C6 (positive) and C14 (negative). If less than .5 volt is present, go to step 6). If not, substitute a known good ECU. If condition goes away, replace original ECU.
  6. On automatic transmission models, disconnect connector "A" from automatic transmission control unit. Recheck voltage, if less than .5 volt is present, go to step 7). If not, replace automatic transmission control unit.
  7. On all models, if less than .5 volt is present, repair short in Red/White wire between ECU terminal C6 and TW sensor.
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