DTC 4
DTC 4: A Problem in the Evaporator Temperature Sensor Circuit1. Disconnect the evaporator temperature sensor 2P connector.
2. Measure the resistance between the No. 1 and No. 2 terminals of the evaporator temperature sensor.
NOTE: Dip the sensor in ice water, and measure resistance. Then pour warm water on the sensor, and check for a change in resistance.
Is the resistance within the specifications shown on the graph?
YES - Go to step 3.
NO - Replace the evaporator temperature sensor.
3. Disconnect the heater control panel 30P connector.
4. Check for continuity between the No. 19 terminal of the heater control panel 30P connector and body ground.
Is there continuity?
YES - Repair short to body ground in the wire between the heater control panel and the evaporator temperature sensor.
NO - Go to step 5.
5. Check for continuity between the No. 19 terminal of the heater control panel 30P connector and the No. 2 terminal of the evaporator temperature sensor 2P connector.
Is there continuity?
YES - Go to step 6.
NO - Repair open in the wire between the heater control panel and the evaporator temperature sensor.
6. Check for continuity between the No. 27 terminal of the heater control panel 30P connector and the No. 1 terminal of the evaporator temperature sensor 2P connector.
Is there continuity?
YES - Check for loose wires or poor connections at the heater control panel 30P connector and at the evaporator temperature sensor 2P connector. If the connections are good, substitute a known-good heater control panel, and recheck. If the symptom/indication goes away, replace the original heater control panel.
NO - Repair open in the wire between the heater control panel and the evaporator temperature sensor.