B0338 Inside Air Temperature Sensor Open


This is the code I am getting and as soon as i try to reset it. I hear the HVAC system making some noises and then the code comes right back while still in the DIC checking for codes.


Where do I even begin trying to trouble shoot this, or anyone know what it could be.

Thanks for any help in advance

Dave

 

bump

 

B0338 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 4.5 volts or higher.
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 B0338 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.
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.
Check for an open in CKT 734.
This step is checking for continuity of CKT 1798.
Repair open in CKT 1798 between HVAC Control Assembly and inside temperature sensor.
This step will replace the inside temperature sensor.
Erase all DTCs and recheck for repair verification.
Replace the HVAC Control Assembly.
Repair the open in CKT 734.

 

foremaw
thanks for that info. its what i needed. I will check this out soon.

again thanks

Dave

 

The thermister is behind the little vent next to the steering column. You might want to carefully pry the cover off and see if it's 'still' there. I found after the dealer did my column lock recall, they wire-tied mine to a brace next to the radio...like it's going to get a correct reading there. You might find a similar situation like that, or maybe they broke it when doing the column like recall (assuming you had it done).