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ECT Sensor 1 Circuit Troubleshooting

WARNING: This page is about a different car, the 2008 Honda Pilot, 2007 Honda Pilot, and 2006 Honda Pilot. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Before performing symptom troubleshooting, check for powertrain DTC (see GENERAL TROUBLESHOOTING INFORMATION ).
  1. Check the malfunction indicator lamp (MIL).

    Does the malfunction indicator lamp come on? 

    YES  - Refer to the fuel and emissions systems DTCs (see GENERAL TROUBLESHOOTING INFORMATION ).

    NO  - Go to step  2.

  2. Turn the ignition switch OFF.
  3. Disconnect the ECT sensor 1 2P connector.
  4. Disconnect climate control unit connector B (30P).
  5. Turn the ignition switch ON (II).
  6. Measure the voltage between the No. 22 terminal of climate control unit connector B (30P) and body ground.
    Fig 1: Measuring Voltage Between No. 22 Terminal Of Climate Control Unit Connector B (30P) & Body Ground
    G04246977Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there about 5 V? 

    YES  - Check for loose wires or poor connections at climate control unit connector B (30P) and at the ECT sensor 1 2P connector. If the connections are good, substitute a known-good climate control unit, and recheck. If the symptom/indication goes away, replace the original climate control unit.

    NO  - Repair open in the wire between the climate control unit and the ECT sensor 1.