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Code 6 - Coolant Temperature (TW) Sensor

  1. Turn ignition off. Remove "EFI/ECU" fuse in under-hood relay panel for 10 seconds to reset ECU. Start engine. Verify if "CHECK ENGINE" light is on. If not, problem is intermittent. Test drive vehicle and check "CHECK ENGINE" light again.
  2. If light is on, warm engine to normal operating temperature (until cooling fan comes on). Disconnect 2-wire coolant sensor connector. Measure resistance across sensor terminals.
  3. If resistance is not 200-400 ohms, replace coolant sensor. If resistance is within specification, measure voltage between ground and Yellow/Green wire of sensor harness. If voltage reading is about 5 volts, go to step 4). If not, go to step 5).
  4. Measure voltage between Yellow/Green (pos.) and Green/White (neg.) terminals. If voltmeter now reads 5 volts, substitute a known good ECU and recheck. If condition is rectified replace original ECU. If 5 volts is not present, repair open in Green/White wire between ECU and coolant sensor.
  5. Turn ignition off. Connect ECU test harness connector "A" between ECU and ECU connectors. Turn ignition on. Measure voltage between terminals A3 (pos.) and A16 (neg.). See Figure . If voltage reading is about 5 volts, repair open Yellow/Green wire between ECU terminal A3 and TW sensor.
  6. If reading is not about 5 volts, disconnect ECU test harness connector "A" from main wire harness side. Measure voltage between terminals A3 (pos.) and A16 (neg.). If reading is not about 5 volts, go to step 7). If voltage reading is about 5 volts, repair short in Yellow/Green wire between ECU terminal A3 and sensor or between TW sensor and A/T control unit.
  7. If voltage reading is still not about 5 volts, substitute a known good ECU. If condition is rectified, replace original ECU.
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