Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Circuit/System Verification
1. Measure actual outside air temperature using a thermometer. Compare this value to the scan tool Outside Air Temp. Raw parameter. The
measured temperature should be within 5 degrees of parameter.
锟斤拷 If not within the specified range, refer to Ambient / Inside Air Temperature Sensor Circuit Malfunction.
2. Measure actual inside air temperature using a thermometer. Compare this value to the scan tool Inside Air Temp. Sensor parameter and Aux.
Inside Air Temp. parameter. The measured temperature should be within 5 degrees of parameter.
锟斤拷 If not within the specified range, refer to Ambient / Inside Air Temperature Sensor Circuit Malfunction.
3. Measure actual temperature using a thermometer at each of the duct temperature sensors. Compare this value to the appropriate scan tool Duct
Actual parameter. The measured temperature should be within 5 degrees of appropriate Duct Actual parameter.
锟斤拷 If not within the specified range, refer to Duct Temperature Sensor Circuit Malfunction.
Circuit/System Testing
Ambient / Inside Air Temperature Sensor Circuit Malfunction
1. Ignition OFF, disconnect the harness connector at the appropriate temperature sensor.
2. Test for less than 1 ohm between the low reference circuit terminal B and ground.
锟斤拷 If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the HVAC
control module.
3. Ignition ON, verify the appropriate scan tool Temp Sensor parameter is greater than 85锟斤拷C (185锟斤拷F).
锟斤拷 If less than the specified range, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the HVAC control
module.
4. Install a 3-amp fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B. Verify the scan tool Temp
Sensor parameter is less than -35锟斤拷C (-39锟斤拷F).
锟斤拷 If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace
the HVAC control module.
5. If all circuits test normal, test or replace the appropriate temperature sensor.
Duct Temperature Sensor Circuit Malfunction
1. Ignition OFF, disconnect the harness connector at the appropriate temperature sensor.
2. Test for less than 1.0 ohm between the low reference circuit terminal 2 and ground.
锟斤拷 If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the HVAC
control module.
3. Ignition ON, verify the appropriate Duct Temp Sensor Actual parameter is greater than 85锟斤拷C (185锟斤拷F).
锟斤拷 If less than the specified range, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the HVAC control
module.
4. Install a 3-amp fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2. Verify the scan tool Duct
Temp Sensor Actual parameter is less than -35锟斤拷C (-39锟斤拷F).
锟斤拷 If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace
the HVAC control module.
5. If all circuits test normal, test or replace the appropriate temperature sensor.
Component Testing
1. Ignition OFF, disconnect the harness connector at the appropriate temperature sensor.
2. Test for the appropriate resistance between the signal terminal A or 1 and the low reference terminal B or 2. Refer to Sensor Resistance Table
for Sensor Resistance Table (See: Heating and Air Conditioning/Specifications/Electrical Specifications) resistance values.
