Inspection Procedure 4

INSPECTION PROCEDURE 4: There is a Discrepancy Between the Actual Ambient Air Temperature and Displayed Temperature, or an Error (CS, OS) Displays.

OUTSIDE TEMPERATURE METER ELECTRONIC COMPASS CIRCUIT
Refer to Symptom Procedures.

CIRCUIT OPERATION
- A thermistor is used for the thermo meter sensor. The resistance value fluctuate according to ambient air temperature. The inside rear view mirror calculates ambient air temperature according to the changes in this resistance value, and displays it on the inside rear view mirror.

TECHNICAL DESCRIPTION (COMMENT)
The thermometer sensor, inside rear view mirror harness, or connector may be defective.

TROUBLESHOOTING HINTS
- Malfunction of the thermo meter sensor
- Malfunction of the inside rear view mirror
- Damaged harness or connector

DIAGNOSIS

STEP 1. Check the thermo meter sensor internal resistance.

1. Remove the thermo meter sensor.






2. Check the internal resistance of the thermo meter sensor are at the standard values at temperature of 20 °C (68 °F) and 40 °C (104 °F).

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

Q: Does the thermo meter sensor resistance meet standard values above?

YES : Go to Step 2.

NO : Replace the thermo meter sensor. Then go to Step 6.

STEP 2. Check connector A-21 at the thermo meter sensor for damage.






Q: Is connector A-21 in good condition?

YES : Go to Step 3.

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

STEP 3. Check the input signal from the thermo meter sensor.






1. Remove the inside rear view mirror.
2. Measure voltage from the rear side of the harness connector D-03 with the connector connected.
3. Turn the ignition switch to the "ON" position.
4. Measure voltage between terminal number 1 and number 4 when the thermo meter sensor is at the following temperatures.
- Voltage should measure approximately 2.90 volts [when 0 °C (32 °F) is displayed]
- Voltage should measure approximately 1.86 volts [when 20 °C (68 °F) is displayed]
- Voltage should measure approximately 1.10 volts [when 40 °C (104 °F) is displayed]

Q: Does the voltage between terminal number 1 and number 4 meet the above values?

YES : Replace the inside rear view mirror. Then go to Step 6.

NO : Go to Step 4.

STEP 4. Check the inside rear view mirror connector D-03 for damage.






Q: Is inside rear view mirror connector D-03 in good condition?

YES : Go to Step 5.

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

STEP 5. Check the wiring harness between thermo meter sensor connector A-21 and inside rear view mirror connector D-03.















NOTE: Also check intermediate connector C-218 and C-116. If intermediate connector C-218 or C-116 is damaged, repair or replace the connector Refer to General (Electrial), Harness Connector Inspection.

Q: Is the wiring harness between thermo meter sensor connector A-21 and inside rear view mirror connector D-03 in good condition?

YES : Go to Step 6.

NO : Repair the wiring harness. Then go to Step 6.

STEP 6. Retest the system.

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

YES : The procedure is complete. (If no malfunctions are found in all steps, an intermittent malfunction is suspected. Refer to General (Body and Chassis), How to Use Troubleshooting/Inspection Service Points -How to Cope with Intermittent Malfunction).

NO: Return to Step 1