Pinpoint Test D: DTC B1A61
Climate Control System
Pinpoint Tests
Pinpoint Test D: DTC B1A61
Refer to Wiring Diagram Set 55, Automatic Climate Control System for schematic and connector information. Diagrams By Number
Normal Operation
Under normal operation, the in-vehicle air temperature sensor receives a ground from the HVAC module through circuit RH107 (GN/BU). A 5-volt reference voltage is supplied to the in-vehicle air temperature sensor from the HVAC module through circuit VH414 (GN/BU).
- DTC B1A61:11 Cabin Temperature Sensor Circuit Open: Circuit Short to Ground - The module senses excessive voltage drop on the sensor reference voltage circuit, indicating a short directly to ground.
- DTC B1A61:15 Cabin Temperature Sensor Circuit Open: 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
- In-vehicle air temperature sensor
- HVAC module
PINPOINT TEST D: DTC B1A61
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D1 CHECK THE SENSOR RESISTANCE
- Ignition OFF.
- Disconnect: In-Vehicle Temperature Sensor C233.
- Measure the resistance between the in-vehicle temperature sensor C233 terminals and compare to the table below.
- Is the resistance within the specified values for the temperatures?
Yes
GO to D2.
No
INSTALL a new in-vehicle temperature sensor. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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D2 CHECK THE SENSOR OUTPUT VOLTAGE
- Ignition ON.
- Measure the voltage between in-vehicle temperature sensor C233-1, circuit VH414 (GN/BU), harness side and C233-2, circuit RH107 (GN/BU), harness side.
- Is the voltage between 4.7 and 5.1 volts?
Yes
INSTALL a new in-vehicle sensor. CLEAR the DTCs. REPEAT the self-test. If code returns, GO to D8.
No
If diagnosing DTC B1A68:15, GO to D3.
If diagnosing DTC B1A68:11, GO to D6.
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D3 CHECK CIRCUIT VH414 (GN/BU) FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: HVAC Module C228a/C2356a.
- Disconnect: HVAC Module C228b/C2356b.
- Ignition ON.
- Measure the voltage between ground and HVAC module C228b/C2356b-21, circuit VH414 (GN/BU), harness side.
- Is any voltage present?
Yes
REPAIR circuit VH414 (GN/BU) for a short to voltage. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
GO to D4.
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D4 CHECK CIRCUIT VH414 (GN/BU) FOR AN OPEN
- Ignition OFF.
- Measure the resistance between HVAC module C228b/C2356b-21, circuit VH414 (GN/BU), harness side and in-vehicle temperature sensor C233-1, circuit VH414 (GN/BU), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to D5.
No
REPAIR circuit VH414 (GN/BU) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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D5 CHECK CIRCUIT RH107 (GN/BU) FOR AN OPEN
- Measure the resistance between HVAC module C228a/C2356a-10, circuit RH107 (GN/BU), harness side and in-vehicle temperature sensor C233-2, circuit RH107 (GN/BU), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to D8.
No
REPAIR circuit RH107 (GN/BU) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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D6 CHECK CIRCUIT VH414 (GN/BU) FOR A SHORT TO CIRCUIT RH107 (GN/BU)
- Ignition OFF.
- Disconnect: HVAC Module C228a/C2356a.
- Disconnect: HVAC Module C228b/C2356b.
- Measure the resistance between in-vehicle temperature sensor C233-1, circuit VH414 (GN/BU), harness side and C233-2, circuit RH107 (GN/BU), harness side.
- Is the resistance greater than 10,000 ohms?
Yes
GO to D7.
No
REPAIR circuit VH414 (GN/BU) for a short to circuit RH107 (GN/BU). CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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D7 CHECK CIRCUIT VH414 (GN/BU) FOR A SHORT TO GROUND
- Measure the resistance between HVAC module C228b/C2356b-21, circuit VH414 (GN/BU), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to D8.
No
REPAIR circuit VH414 (GN/BU) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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D8 CHECK THE MODULE CONNECTION
- Carry out the HVAC Module Cold Boot Process. HVAC Module Cold Boot Process
- Carry out the HVAC Module On-Demand Self Test. Alternate Diagnostic Methods - HVAC Module
- Operate the system.
- Does the concern return?
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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