Pinpoint Test F: DTC B1259 or B1261
Climate Control System
Pinpoint Tests
Pinpoint Test F: DTC B1259 or B1261
Refer to Wiring Diagram Set 55, Automatic Climate Control System for schematic and connector information. Diagrams By Number
Normal Operation
Under normal operation, the solar radiation sensor receives a ground through circuit 676 (PK/OG). A 5-volt reference voltage is supplied to the solar radiation sensor from the HVAC module through circuits 476 (BN/YE) (LH) and 468 (BN) (RH).
- DTC B1261 Solar Radiation Sensor Circuit Short To Ground - The module senses excessive voltage drop on the sensor reference voltage circuit, indicating a short directly to ground.
- DTC B1259 Solar Radiation Sensor Circuit Open - The module senses no voltage drop on the sensor reference voltage circuit, indicating an open circuit.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Solar radiation sensor
- HVAC module
PINPOINT TEST F: DTC B1259 OR B1261
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F1 CHECK THE HVAC MODULE OUTPUT VOLTAGE
- Ignition OFF.
- Disconnect: Solar Radiation Sensor C287.
- Ignition ON.
- Press the AUTOMATIC button.
- Measure the voltage between solar radiation sensor C287-6, circuit 468 (BN), harness side and C287-5, circuit 676 (PK/OG), harness side.
- Measure the voltage between solar radiation sensor C287-5, circuit 676 (PK/OG), harness side and C287-1, circuit 476 (BN/YE), harness side.
- Are the voltages between 4.7 and 5.1 volts?
Yes
INSTALL a new solar radiation sensor. CLEAR the DTCs. REPEAT the self-test. If the DTC returns, GO to F6.
No
If diagnosing DTC B1259, GO to F2.
If diagnosing DTC B1261, GO to F4.
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F2 CHECK CIRCUITS 468 (BN) AND 476 (BN/YE) FOR AN OPEN
- Ignition OFF.
- Disconnect: HVAC Module C228b.
- Measure the resistance between HVAC module C228b-6, circuit 468 (BN), harness side and solar radiation sensor C287-6, circuit 468 (BN), harness side.
- Measure the resistance between HVAC module C228b-18, circuit 476 (BN/YE), harness side and solar radiation sensor C287-6, circuit 476 (BN/YE), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to F3.
No
REPAIR the circuit for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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F3 CHECK CIRCUIT 676 (PK/OG) FOR AN OPEN
- Measure the resistance between solar radiation sensor C287-5, circuit 676 (PK/OG), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to F6.
No
REPAIR circuit 676 (PK/OG) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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F4 CHECK CIRCUITS 468 (BN) AND 476 (BN/YE) FOR A SHORT TO CIRCUIT 676 (PK/OG)
- Ignition OFF.
- Disconnect: HVAC Module C228b.
- Measure the resistance between solar radiation sensor C287-6, circuit 468 (BN), harness side and C287-5, circuit 676 (PK/OG), harness side.
- Measure the resistance between solar radiation sensor C287-1, circuit 476 (BN/YE), harness side and C287-5, circuit 676 (PK/OG), harness side.
- Are the resistances greater than 10,000 ohms?
Yes
GO to F5.
No
REPAIR circuit 468 (BN) or 476 (BN/YE) for a short to circuit 676 (PK/OG). CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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F5 CHECK CIRCUITS 468 (BN) AND 476 (BN/YE) FOR A SHORT TO GROUND
- Measure the resistance between solar radiation sensor C287-6, circuit 468 (BN), harness side and ground.
- Measure the resistance between solar radiation sensor C287-1, circuit 476 (BN/YE), harness side and ground.
- Are the resistances greater than 10,000 ohms?
Yes
GO to F6.
No
REPAIR circuit 468 (BN) or 476 (BN/YE) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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F6 CHECK HVAC MODULE CONNECTION
- Carry out the HVAC Module Cold Boot Process. HVAC Module Cold Boot Process
- Carry out the HVAC Module On-Demand Self Test. HVAC Module Self-Test
- 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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