Code 4/26323

Cabin temperature sensor - testing

Fault symptom

Permanent: 46323
Intermittent: 26323

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

Testing

ISAT scan tool command: 250

Display shows:
Cabin temperature = +10° C 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, refer to "Code 4/22521" Code 4/22521

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).


Important : 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 k Ohms within the range 0° to +40° C (32 - 104° F). Some specific readings at various temperatures:

°C °F Minimum Maximum
(k Ohm) (k Ohm)
0° C 32 30.0 34.8
+10 50 18.5 21.1
+20° C 68 11.7 13.1
+25° C 77 9.5 10.5
+30° C 86 7.6 8.5
+40° C 104 4.9 5.6

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:
Install 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, reinstall 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: (Measure with ACC control module connected and ignition on.)

(Battery positive voltage - 1.5) x R sensor) / R sensor + 10 k Ohm) = Z

Where Z is the voltage on pin 1.

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