| Table 1: | DTC B0337 - Inside Air Temperature Sensor Circuit Short To Ground (CJ2) |
Circuit Description
The inside air temperature sensor is located in the air outlet vent at the RH side of the steering column. In this position, it is exposed to the air that is present in the passenger compartment. This provides a sample of the inside air temperature to the sensor.
The sensor is a thermistor used to control the signal voltage at the HVAC Control Assembly. The HVAC Control Assembly supplies a reference voltage (about 5 volts internally) to the sensor and measures the voltage drop in the circuit to obtain a temperature signal. This signal is an input that tells the HVAC Control Assembly how much cooling or heating will be required for the passenger compartment. When the inside air temperature is cold, the thermistor resistance is high; therefore, the HVAC Control Assembly will receive a high signal voltage input. If the inside air temperature is hot, the thermistor resistance is low, the HVAC Control Assembly will receive a low signal voltage input.
Conditions for Setting the DTC
| • | With the ignition in the ON position, CKT 734 is checked continuously. |
| • | CKT 734 stays at or near zero voltage. |
Action Taken When the DTC Sets
| • | The system will use 24°C (75°F) as a default value. |
| • | The HVAC Control Assembly stores a DTC B0337 in memory. |
Conditions for Clearing the DTC
| • | Using the IPC clearing feature. |
| • | Using a scan tool. |
| • | A history DTC will clear after 50 consecutive ignition cycles if the conditions for the fault is no longer present. |
Diagnostic Aids
| • | If the DTC is a history or an intermittent. Try to perform the tests shown while "wiggling" wiring and connectors, this can often cause the malfunction to appear. |
| • | Visually inspect sensor connector and harness for damage, corrosion or water intrusion. |
| • | Check for adequate terminal tension, mis-routed harness, rubbed through wire insulation, and broken wire inside insulation. |
| • | The resistance value of the sensor must be close to the values given in the chart. If not the sensor is considered skewed and must be replaced. |
°C | °F | Ohmsohms |
|---|---|---|
Temperature vs. Resistance Values (Approximate) | ||
-40 | -40 | 100,701 |
-30 | -22 | 52,671 |
-20 | -4 | 28,661 |
-10 | 14 | 16,159 |
0 | 32 | 9,407 |
10 | 50 | 5,666 |
20 | 68 | 3,514 |
30 | 86 | 2,237 |
40 | 104 | 1,459 |
50 | 122 | 973 |
60 | 140 | 667 |
Test Description
The numbers below refer to the step numbers on the diagnostic table:
-
This test checks for the 5 volt reference signal being sent from the HVAC Control Assembly along CKT 734.
-
Checks for a short to ground in CKT 734.
-
Replace the inside temperature sensor.
-
Erase all DTCs and recheck for repair verification.
-
Replace the HVAC Control Assembly.
-
Repair the short to ground in CKT 734.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Were you sent here from the HVAC System Check (CJ2)? | -- | Go to HVAC System Check | |
2 |
Is the voltage within the specified values? | 4.0-6.0V | ||
3 |
Is the resistance within specified values? | Infinite | ||
4 | Replace the inside air temperature sensor. Refer to Inside Air Temperature Sensor Replacement . Is the replacement complete? | -- | -- | |
5 | Using a scan tool, clear all DTCs from memory. Refer to Diagnostic Trouble Code (DTC) Clearing . Do all DTCs erase from memory? | -- | Go to HVAC System Check | Go to appropriate DTC table for diagnosis |
6 | Replace the HVAC Control Assembly. Refer to Control Assembly Replacement . Is the replacement complete? | -- | -- | |
7 | Locate and repair a short to ground in CKT 734. Is the repair complete? | -- | -- |
