46323/26323

Fault symptom
Permanent: 46323
Intermittent: 26323

Conditions
Cabin temperature sensor: Open circuit on pin 1 or 2 or 12 V on pin 1 in ACC control module or fault in ACC control module monitoring circuit.





Cabin Temperature Sensor - Testing
ISAT scan tool command: 250
Display shows:
Cabin temperature = +10 to +40 °C
If the display shows +18 °C, the fault may be open circuit to pin 1 or 2.
Battery positive voltage on pin 1.
Battery positive voltage on pin 2, 42521/22521

If the display shows +40 °C (with cold air) the fault may be short between pins 1 and 2 (no diagnostic trouble code).
Pin 1 is connected to ground (no diagnostic trouble code).

NOTE: At temperatures below 0 °C, the cabin temperature sensor and blended air temperature sensor cannot be tested.

Action
1. Unplug the ACC control module's 39 pin connector and check the resistance across pins 1 and 2. Reading varies between 5 and 35 kOhm within the range 0 to +40 °C (32 - 104 °F). Some specific readings at various temperatures:

0 °C (32 °F) - 30.0 Min. to 34.8 Max.kOhm
+10 °C (50 °F) - 18.5 Min. to 21.1 Max.kOhm
+20 °C (68 °F) - 11.7 Min. to 13.1 Max.kOhm
+25 °C (77 °F) - 9.5 Min. to 10.5 Max.kOhm
+30 °C (86 °F) - 7.6 Min. to 8.5 Max.kOhm
+40 °C (104 °F) - 4.9 Min. to 5.6 Max.kOhm

2. If reading is incorrect, unplug the temperature sensor connector and repeat measurements of resistance across pins 2 and 3 in the connector. If reading is still incorrect fit new temperature sensor.

3. If the reading is correct across the temperature sensor connector, check for open circuit between the sensor connector and the ACC control module's 39 pin connector (pins 2 and 2, pins 3 and 1). If there is no fault, refit the connector, erase all diagnostic trouble codes, restart the system and check if the fault remains.

4. If the fault is still present, measure voltage on pin 1 in the ACC control module's 39 pin connector. This varies depending on sensor resistance and battery positive voltage according to the following formula:

NOTE: Measure with ACC control module connected and ignition on.

(Battery positive voltage - 1.5) x R sensor
-------------------------------------------------- = Z
R sensor + 10 kOhm

Where Z is the voltage on pin 1.

5. If voltage is incorrect, try a new ACC control module.