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 sunload sensor receives a ground from the HVAC module. As the light applied to the sensor changes, the PCM detects the change through the RH and LH feedback circuits.
- DTC B1259 (Solar Radiation Sensor Circuit Open) - The module senses no voltage drop on the sensor reference voltage circuit, indicating an open circuit.
- 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.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Solar radiation sensor
- HVAC module - Dual Automatic Temperature Control (DATC)
PINPOINT TEST F: DTC B1259 OR B1261
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F1 CHECK THE HVAC MODULE OUTPUT VOLTAGE
- Ignition OFF.
- Disconnect: Solar Radiation Sensor C286.
- Ignition ON.
- Press the AUTOMATIC button.
- Measure the voltage between solar radiation sensor C286-1, circuit VH417 (YE/OG), harness side and C286-5, circuit GD145 (BK/BU), harness side.
- Measure the voltage between solar radiation sensor C286-5, circuit GD145 (BK/BU), harness side and C286-6, circuit VH416 (VT/GY), 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 code returns, GO to F6.
No
For DTC B1259, GO to F2.
For DTC B1261, GO to F4.
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F2 CHECK CIRCUITS VH416 (VT/GY) AND VH417 (YE/OG) FOR AN OPEN
- Ignition OFF.
- Disconnect: HVAC Module - DATC C228A.
- Measure the resistance between HVAC module - DATC C228A-18, circuit VH417 (YE/OG), harness side and solar radiation sensor C286-1, circuit VH417 (YE/OG), harness side.
- Measure the resistance between HVAC module - DATC C228A-16, circuit VH416 (VT/GY), harness side and solar radiation sensor C286-6, circuit VH416 (VT/GY), harness side.
- Are the resistances less than 5 ohms?
Yes
GO to F3.
No
REPAIR circuit VH416 (VT/GY) or VH417 (YE/OG) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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F3 CHECK CIRCUIT GD145 (BK/BU) FOR AN OPEN
- Measure the resistance between ground and solar radiation sensor C286-5, circuit GD145 (BK/BU), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to F6.
No
REPAIR circuit GD145 (BK/BU) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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F4 CHECK CIRCUITS VH416 (VT/GY) AND VH417 (YE/OG) FOR A SHORT TO CIRCUIT GD145 (BK/BU)
- Ignition OFF.
- Disconnect: HVAC Module - DATC C228A.
- Measure the resistance between solar radiation sensor C286-1, circuit VH417 (YE/OG), harness side and circuit C286-5, GD145 (BK/BU), harness side.
- Measure the resistance between solar radiation sensor C286-6, circuit VH416 (VT/GY), harness side and circuit C286-5, GD145 (BK/BU), harness side.
- Are the resistances greater than 10,000 ohms?
Yes
GO to F5.
No
REPAIR circuit VH416 (VT/GY) or VH417 (YE/OG) for a short to circuit GD145 (BK/BU). CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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F5 CHECK CIRCUITS VH416 (VT/GY) AND VH417 (YE/OG) FOR A SHORT TO GROUND
- Measure the resistance between ground and solar radiation sensor C286-1, circuit VH417 (YE/OG), harness side.
- Measure the resistance between ground and solar radiation sensor C286-6, circuit VH416 (VT/GY), harness side.
- Are the resistances greater than 10,000 ohms?
Yes
GO to F6.
No
REPAIR circuit VH416 (VT/GY) or VH417 (YE/OG) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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F6 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. 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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