Perform the following to see if you can come up with anything.
CLIMATE CONTROL SYSTEM
How to Retrieve a DTC
The climate control unit has a self-diagnostic function.
Running the Self-diagnostic Function
1. Turn the ignition switch ON (II).
2. Press the AUTO button and then the OFF button. Continue to hold both buttons down for 1 minute. If there is any abnormality in the system, the temperature indicator will light up the segment (A through N) corresponding to the error. If no DTCs are found, go to SYMPTOM TROUBLESHOOTING INDEX. The temperature indicator will then alternate every second between displaying "88" (all segments lit) and the error code segment (A through N).
The system will only display the DTC when the AUTO and OFF buttons are pressed. If you release the buttons, the display will go blank. To return the display, simply press the AUTO then the OFF buttons again.
To determine the meaning of the DTC, refer to the DTC TROUBLESHOOTING INDEX. If there is no abnormality, the segments will not light up.
If there are no DTC's detected (no opens or shorts in the climate control circuits or sensors), and the system is still not operating properly, check the sensor input to the climate control unit.
Cancelling the Self-diagnostic Function
3. Turn the ignition switch OFF to cancel the self-diagnostic function. After completing repair work, run the self-diagnostic function again to make sure that there are no other malfunctions.
DISPLAYING SENSOR INPUTS AT THE CLIMATE CONTROL UNIT
The climate control unit has a mode that displays sensor inputs it receives. This mode shows you what the climate control unit is receiving from each of the sensors, one at a time, and it can help you determine if a sensor is faulty.
Check these items before using the sensor input display mode:
1. Turn the ignition switch ON (II), and check the recirculation door function; press the recirculation button to switch from FRESH to RECIRC. The air volume and sound should change slightly.
2. Set the temperature control **** to the desired test temperature. When selecting the test temperatures, note these items:
"Lo" temperature setting will default to MAX COOL, VENT, and RECIRC.
"Hi" temperature setting will default to MAX HOT, FLOOR, and FRESH.
61 through 89 F settings will use the automatic climate control logic.
3. Turn the ignition switch OFF.
To run the sensor input display mode, follow these steps:
1. Turn the ignition switch OFF.
2. Press and hold both the AUTO and RECIRC buttons, then start the engine.
3. After the engine starts, release the buttons. The climate control display will flash the sensor number and then the value for that sensor. Record the value displayed.
4. To advance to the next sensor, press the rear window defogger button.
The sensor values will be displayed in degrees Celsius ( C) or an alphanumeric code. Use the chart to convert the value to degrees Fahrenheit ( F).
If the sensor value displays "Er, " this indicates there is an open or short in the circuit or sensor. Run the self-diagnostic function to check for a DTC.
If necessary, compare the sensor input display to an alike, known-good vehicle under the same test conditions.
If the sensor is out of the normal range, refer to the sensor test, or substitute the sensor with a known-good sensor, and recheck.
5. To cancel the sensor input display mode, press the AUTO button, or turn the ignition OFF.
Images (click to enlarge)
Friday, December 10th, 2010 AT 3:56 PM