Pinpoint Test C: DTC B2826 or B2827
Climate Control System
Pinpoint Tests
Pinpoint Test C: DTC B2826 or B2827
Refer to Wiring Diagram Set 54, Manual Climate Control System for schematic and connector information. Diagrams By Number
Normal Operation
Under normal operation, the evaporator discharge air temperature sensor receives a ground from the HVAC module. The sensor varies its resistance with the temperature. As the temperature rises, the resistance falls. As the temperature falls the resistance rises. The HVAC module measures this resistance to determine the temperature at the sensor.
- DTC B2826 (Front Evaporator Temp Sensor Circuit Failure) - The module senses no voltage drop on the sensor reference voltage circuit, indicating an open circuit.
- DTC B2827 (Front Evaporator Temp Sensor Short to Ground) - The module senses excessive voltage drop on the sensor reference voltage circuit, indicating a short directly to ground.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Evaporator discharge air temperature sensor
- HVAC module
PINPOINT TEST C: DTC B2826 OR B2827
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C1 CHECK THE SENSOR RESISTANCE
- Ignition OFF.
- Disconnect: Evaporator Discharge Air Temperature Sensor C296.
- Allow enough time for the evaporator to stabilize to the outside ambient temperature.
- Measure the resistance between evaporator discharge air temperature sensor C296 terminals and compare to the table below.
- Is the resistance within the specified values for the temperatures?
Yes
GO to C2.
No
INSTALL a new evaporator discharge air temperature sensor. REFER to Climate Control Service and Repair. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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C2 CHECK THE HVAC SENSOR OUTPUT VOLTAGE
- Ignition ON.
- Press the Power button.
- Measure the voltage between evaporator discharge air temperature sensor C296-2, circuit CH206 (YE/VT), harness side and C296-1, circuit RH111 (GY/BU), harness side.
- Is the voltage between 4.7 and 5.1 volts?
Yes
INSTALL a new evaporator discharge air temperature sensor. REFER to Climate Control Service and Repair. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. If code returns, GO to C7.
No
For DTC B2826, GO to C3.
For DTC B2827, GO to C5.
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C3 CHECK CIRCUIT CH206 (YE/VT) FOR AN OPEN
- Ignition OFF.
- Disconnect: HVAC Module C2357A.
- Measure the resistance between HVAC module C2357A-6, circuit CH206 (YE/VT), harness side and evaporator discharge air temperature sensor C296-2, circuit CH206 (YE/VT), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to C4.
No
REPAIR circuit CH206 (YE/VT) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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C4 CHECK CIRCUIT RH111 (GY/BU) FOR AN OPEN
- Measure the resistance between HVAC module C2357A-10, circuit RH111 (GY/BU), harness side and evaporator discharge air temperature sensor C296-1, circuit RH111 (GY/BU), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to C7.
No
REPAIR circuit RH111 (GY/BU) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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C5 CHECK CIRCUITS CH206 (YE/VT) AND RH111 (GY/BU) FOR A SHORT TOGETHER
- Ignition OFF.
- Disconnect: HVAC Module C2357A.
- Measure the resistance between evaporator discharge air temperature sensor C296-2, circuit CH206 (YE/VT), harness side and C296-1, circuit RH111 (GY/BU), harness side.
- Is the resistance greater than 10,000 ohms?
Yes
GO to C6.
No
REPAIR circuits CH206 (YE/VT) and RH111 (GY/BU) for a short together. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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C6 CHECK CIRCUIT CH206 (YE/VT) FOR A SHORT TO GROUND
- Measure the resistance between HVAC module C2357A-6, circuit CH206 (YE/VT), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to C7.
No
REPAIR circuit CH206 (YE/VT) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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C7 CHECK THE HVAC MODULE CONNECTION
- Disconnect and inspect the HVAC module connectors for:
- corrosion.
- pushed-out terminals.
- damaged terminals.
- Connect and correctly seat all the HVAC module connectors.
- Clear the DTCs.
- Operate the system.
- Enter the following diagnostic mode on the scan tool: Self Test - HVAC Module.
- Do the DTCs return?
Yes
INSTALL a new HVAC module. REFER to Climate Control Heating Ventilation Air Conditioning (HVAC) Module. TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.
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