Inspection Procedure 7

INSPECTION PROCEDURE 7: There is a Discrepancy Between the Actual Ambient Air Temperature and Displayed Temperature or an Error Displays (SC, OC).

Outside Temperature Meter Electronic Compass Circuit

CIRCUIT OPERATION
A thermistor is used for the ambient air temperature sensor. The resistance value fluctuate according to ambient air temperature. The inside rear view mirror (with compass and temperature display) calculates ambient air temperature according to the changes in this resistance value and displays it on the inside rear view mirror (with compass and temperature display).




STEP 1. Check that the indicator illuminates.

1. Turn the ignition switch to "ON" position.
2. Make sure the green indicator on.
3. If it's not, press the display switch for more than 6 seconds, less than 9 seconds, until the indicator illuminates.

Q: Does the indicator illuminate?

YES: Go to Step 2.
NO: Refer to Inspection procedure.




STEP 2. Check the ambient air temperature sensor internal resistance.
1. Remove the ambient air temperature sensor.
2. Check the internal resistance of the ambient air temperature sensor are at the standard values at temperature of20° C (68° F) and 40° C (104° F).

Standard value:
Approximately 1,200 ohms [at 20° C (68° F)]
Approximately 500 ohms [at 40° C (104° F)]

Q: Does the ambient air temperature sensor resistance meet standard values above?

YES: Go to Step 4.
NO: Go to Step 3.




STEP 3. Check the connector A-29 at the ambient air temperature sensor for damage.

Q: Is the connector A-29 in good condition?

YES: Go to Step 7.
NO: Repair or replace the connector. Then go to Step 7.




STEP 4. Check the input signal from the ambient air temperature sensor.
1. Disconnect the inside rear view mirror (with compass and temperature display) connector D-04 and measure at the harness side.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal number 4 and number 5 when the ambient air temperature sensor is at the following temperatures.

- Voltage should be approximately 2.90 volts [when 0° C (32° F) is displayed]
- Voltage should be approximately 1.86 volts [when 20° C (68° F) is displayed]
- Voltage should be approximately 1.10 volts [when 40° C [when104° F) is displayed]

Q: Does the voltage between terminal number 4 and number 5 meet the above values?

YES: Replace the inside rear view mirror (with compass and temperature display).Then goto Step 7.
NO: Go to Step 5.




STEP 5. Check the inside rear view mirror (with compass and temperature display) connector D-04 for damage.

Q: Is inside rear view mirror (with compass and temperature display) connector D-04 in good condition?

YES: Go to Step 6.
NO: Repair or replace the connector. Then go to Step 7.







STEP 6. Check the wiring harness between ambient air temperature sensor connector A-29 (terminal 1 and 2) and inside rear view mirror (with compass and temperature display) connector D-04 (terminal 4 and 5).




NOTE: Also check intermediate connector C-28 and C-209. If intermediate connector C-28 or C-209 is damaged, repair or replace the connector.Harness Connector Inspection.

Q: Is the wiring harness between ambient air temperature sensor connector A-29 (terminal 1 and 2) and inside rear view mirror (with compass and temperature display) connector D-04 (terminal 4 and 5) in good condition?

YES: Go to Step 7.
NO: Repair the wiring harness. Then go to Step 7.

STEP 7. Retest the system.

Q: Is there any discrepancy between the actual ambient air temperature and displayed temperature, or is any error (SC, OC) displayed?

YES: Replace the inside rear view mirror (with compass and temperature display).
NO: There is no action to be taken.