Pinpoint Test G: DTC B1B71:11 Or B1B71:15
Climate Control System
Pinpoint Tests
Pinpoint Test G: DTC B1B71:11 or B1B71:15
Refer to Wiring Diagram Set 54, Manual Climate Control System for schematic and connector information. Diagrams By Number
Refer to Wiring Diagram Set 55, Automatic Climate Control System for schematic and connector information. Diagrams By Number
Normal Operation
Under normal operation, the evaporator 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 B1B71:11 (Evaporator Temperature Sensor: Circuit Short to Ground) - The module senses excessive voltage drop on the sensor reference voltage circuit, indicating a short directly to ground.
- DTC B1B71:15 (Evaporator Temperature Sensor: Circuit Short to Battery or Open) - The module senses no voltage drop on the sensor reference voltage circuit, indicating a short directly to voltage or an open circuit.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Evaporator temperature sensor
- HVAC module
PINPOINT TEST G: DTC B1B71:11 OR B1B71:15
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G1 CHECK THE SENSOR RESISTANCE
- Ignition OFF.
- Disconnect: Evaporator Temperature Sensor C296.
- Measure the resistance between the evaporator temperature sensor C296 terminals and compare to the table below.
- Is the resistance within the specified values for the temperatures?
Yes
GO to G2.
No
INSTALL a new heater core and evaporator core housing. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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G2 CHECK THE SENSOR OUTPUT VOLTAGE
- Ignition ON.
- Press the AUTO button.
- Measure the voltage between evaporator temperature sensor C296-1, circuit VH406 (VT/BN), harness side and C296-2, circuit RH111 (GY/BU), harness side.
- Is the voltage between 4.7 and 5.1 volts?
Yes
GO to G8.
No
For DTC B1B71:15, GO to G3.
For DTC B1B71:11, GO to G6.
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G3 CHECK CIRCUIT VH406 (VT/BN) FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: HVAC Module - Electronic Manual Temperature Control (EMTC) C294A.
- Disconnect: HVAC Module - Dual Automatic Temperature Control (DATC) C228A/C2109A.
- Ignition ON.
For vehicles without navigation
- For vehicles without navigation, measure the voltage between ground and HVAC module - EMTC C294A-19 or HVAC module - DATC C2109A-19, circuit VH406 (VT/BN), harness side and ground.
For vehicles with navigation
- For vehicles with navigation, measure the voltage between ground and HVAC module - DATC C228A-6, circuit VH406 (VT/BN), harness side and ground.
- Is any voltage present?
Yes
REPAIR circuit VH406 (VT/BN) for a short to voltage. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
GO to G4.
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G4 CHECK CIRCUIT VH406 (VT/BN) FOR AN OPEN
- Ignition OFF.
For vehicles without navigation
- For vehicles without navigation, measure the resistance between HVAC module - EMTC C294A-19 or HVAC module - DATC C2109A-19, circuit VH406 (VT/BN), harness side and evaporator temperature sensor C296-1, circuit VH406 (VT/BN), harness side.
For vehicles with navigation
- For vehicles with navigation, measure the resistance between HVAC module - DATC C228A-6, circuit VH406 (VT/BN), harness side and evaporator temperature sensor C296-1, circuit VH406 (VT/BN), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to G5.
No
REPAIR circuit VH406 (VT/BN) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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G5 CHECK CIRCUIT RH111 (GY/BU) FOR AN OPEN
For vehicles without navigation
- For vehicles without navigation, measure the resistance between HVAC module - EMTC C294A-23 or HVAC module - DATC C2109A-23, circuit RH111 (GY/BU), harness side and evaporator temperature sensor C296-2, circuit RH111 (GY/BU), harness side.
For vehicles with navigation
- For vehicles with navigation, measure the resistance between HVAC module - DATC C228A-10, circuit RH111 (GY/BU), harness side and evaporator temperature sensor C296-2, circuit RH111 (GY/BU), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to G8.
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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G6 CHECK CIRCUIT VH406 (VT/BN) FOR A SHORT TO CIRCUIT RH111 (GY/BU)
- Ignition OFF.
- Disconnect: HVAC Module - EMTC C294A.
- Disconnect: HVAC Module - DATC C228A/C2109A.
- Measure the resistance between evaporator temperature sensor C296-1, circuit VH406 (VT/BN), harness side and C296-2, circuit RH111 (GY/BU), harness side.
- Is the resistance greater than 10,000 ohms?
Yes
GO to G7.
No
REPAIR circuit VH406 (VT/BN) for a short to circuit RH111 (GY/BU). CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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G7 CHECK CIRCUIT VH406 (VT/BN) FOR A SHORT TO GROUND
For vehicles without navigation
- For vehicles without navigation, measure the resistance between HVAC module - EMTC C294A-19 or HVAC module - DATC C2109A-19, circuit VH406 (VT/BN), harness side and ground.
For vehicles with navigation
- For vehicles with navigation, measure the resistance between HVAC module - DATC C228A-6, circuit VH406 (VT/BN), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to G8.
No
REPAIR circuit VH406 (VT/BN) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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G8 CHECK THE HVAC MODULE CONNECTION
- 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 and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new 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. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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