B0158
DTC B0158 or B0163
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
DTC Descriptors
DTC B0158 03
- Outside Air Temperature Sensor Voltage Below Thershold
DTC B0158 07
- Outside Air Temperature Sensor Voltage Above Thershold
DTC B0163 06
- Passenger Compartment Temp Sensor Circuit Short to Ground or Open
Diagnostic Fault Information
Circuit/System Description
The HVAC control module monitors the air temperature sensors with a low reference circuit and 5-volt signal circuit. The HVAC control module monitors the voltage drop across the sensor, which is proportional to temperature. When the ambient air temperatures are cold, the resistance of the sensor is high and the voltage signals are high. When the ambient air temperatures are hot, the resistance of the sensors is low and the voltage signals are low.
Conditions for Running the DTC
Ignition ON.
Conditions for Setting the DTC
* The HVAC control module detects the sensor signal circuit is less than -35°C (-39°F).
* The HVAC control module detects the sensor signal circuit is greater than 85°C (185°F) .
Action Taken When the DTC Sets
* The HVAC control module uses a default air temperature value for further automatic control calculations. The default values are not displayed on the scan tool.
* SERVICE A/C SYSTEM will be displayed on the DIC.
Conditions for Clearing the DTC
* The DTC will become history if the HVAC control module no longer detects a failure.
* The history DTC will clear after 50 fault-free ignition cycles.
Reference Information
Schematic Reference
HVAC Schematics (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
* Air Temperature Description and Operation (Air Temperature Description and Operation)
* Air Delivery Description and Operation (Air Delivery Description and Operation)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
Ignition ON, observe the appropriate air temperature sensor. The reading should be between -35°C (-39°F) and 85°C (185°F) and change with air temperature changes.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the appropriate air temperature sensor.
2. Ignition OFF, test for less than 10 ohms between the low reference circuit terminal listed below and ground:
* Ambient air temperature sensor terminal B
* Inside air temperature sensor terminal 1
• 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 scan tool appropriate Air Temp Sensor parameter is less than -35°C (-39°F).
• If greater than the specified range, test the signal circuit terminal listed below for a short to ground. If the circuit tests normal, replace the HVAC control module.
* Ambient air temperature sensor terminal A
* Inside air temperature sensor terminal 2
4. Install a 3A fused jumper wire between the signal circuit terminal listed below and the low reference circuit terminal listed below. Verify the scan tool Air Temp Sensor parameter is greater than 85°C (185°F).
* Ambient air temperature sensor signal circuit terminal A and low reference circuit terminal B
* Inside air temperature sensor signal circuit terminal 2 and low reference circuit terminal 1
• If less 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 air temperature sensor.
Component Testing
1. Test the appropriate air temperature sensor by varying the sensor temperature while monitoring the sensor resistance.
2. Compare the readings with the Temperature VS Resistance table Sensor Resistance Table (Electrical Specifications) , and verify that the resistance is within 5 percent of the specification.
• If not within the specified range, replace the sensor.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Ambient Air Temperature Sensor Replacement (Service and Repair)
* Inside Air Temperature Sensor Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for HVAC control module replacement, setup, and programming