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Home >> Honda >> 1991 >> Civic Base, 2D Hatchback >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Diagnostic Codes >> Code 6 - Coolant Temperature (TW) Sensor
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Code 6 - Coolant Temperature (TW) Sensor

  1. Turn ignition off. Remove ECU fuse for 10 seconds to reset ECU. Start engine. Verify if CHECK ENGINE light is on and if LED is flashing Code 6. If LED is flashing Code 6, go to next step. If LED is not flashing Code 6, problem is intermittent. Check connectors at TW sensor and related circuits.
  2. Warm engine to normal operating temperature (cooling fan comes on). Disconnect 2-wire connector from TW sensor. Turn ignition off. Measure resistance between terminals on TW sensor. If resistance is not between 200-400 ohms, replace sensor. If sensor resistance is okay, go to next step.
  3. Turn ignition on. Measure voltage between ground and Red/White wire on sensor harness. If voltage is not about 5 volts, go to step 5). If voltage is about 5 volts, measure voltage between Red/White (+) and Green/White (-) wires. If reading is not about 5 volts, repair open in Green/White wire between ECU and coolant sensor.
  4. If voltage reading from Green/White wire to Red/White wire of coolant sensor harness is about 5 volts, substitute a known good ECU. If Code 6 does not reset, replace original ECU.
  5. If voltage reading from ground to Red/White wire of coolant sensor harness is not about 5 volts in step 3), repair short in Red/White wire between ECU terminal C6 and TW sensor.
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