B1259 Code Meaning, Symptoms, Causes, & How to Fix

The B1259 code indicates a potential problem with the solar radiation sensor or the Electronic Automatic Temperature Control (EATC) module in a vehicle. It is important to address this code promptly to avoid further damage or performance issues.

Symptoms of the B1259 code may include erratic temperature readings, inconsistent air conditioning performance, or a malfunctioning climate control system.

Possible causes for the B1259 code include a faulty solar radiation sensor, a malfunctioning EATC module, or wiring issues.

To fix the B1259 code, it is recommended to consult with a professional for an accurate diagnosis and repair procedures. They will be able to determine the specific cause and provide the appropriate solutions. The complexity and cost of the repair may vary depending on the vehicle’s make, model, and engine type.

B1259 Code: Malfunction with the Solar Radiation Sensor

What does it mean

The code B1259 indicates a malfunction with the Solar Radiation Sensor in the vehicle’s Electronic Automatic Temperature Control (EATC) Module. This sensor measures sunlight intensity to adjust temperature control.

Troubleshooting involves inspecting wiring and connectors for damage, checking for broken or corroded pins, and following appropriate repair procedures.

Ignoring the code can lead to improper temperature control and decreased performance. Promptly addressing the issue ensures optimal functionality.

What are the symptoms

The symptoms of code B1259 may include the Engine Light or Service Engine Soon Warning Light turning on. There might also be other symptoms specific to the vehicle.

Here are five potential signs that may indicate the presence of this code:

1. Decreased fuel efficiency: The vehicle may not be as fuel efficient, resulting in more frequent trips to the gas station.
2. Poor engine performance: The engine may not run smoothly or efficiently, leading to a decrease in overall vehicle performance.
3. HVAC system issues: The heating, ventilation, and air conditioning system may not work properly, causing uncomfortable cabin temperatures.
4. Electrical system malfunctions: Various electrical components like power windows, door locks, or dashboard controls may not function correctly.
5. Potential long-term consequences: Ignoring the code and not fixing the underlying issue promptly can cause further damage or performance problems, which may result in expensive repairs or engine failure.

To prevent any potential long-term consequences and restore the vehicle’s performance, it is important to consult a professional for proper diagnosis and repair.

What are the causes

Possible causes of code B1259 include:

• A faulty solar radiation sensor
• A problem with the sensor harness (such as an open or shorted circuit)
• Poor electrical connections in the sensor circuit
• A faulty Electronic Automatic Temperature Control (EATC) Module
• Other potential causes that are not listed

What Tools are Needed to diagnose

To diagnose code B1259 and find the underlying issue, you need specialized diagnostic tools and equipment. These tools help technicians accurately identify the problem and make the necessary repairs.

Here are five commonly used methods and tools for the B1259 code:

1. OBD-II scanner: This tool connects to the vehicle’s onboard computer system and retrieves the specific diagnostic trouble code. It provides valuable information and helps pinpoint the issue.
2. Multimeter: A multimeter measures voltage, resistance, and continuity in electrical circuits. Technicians use it to test the solar radiation sensor and related components for proper functioning.
3. Wiring diagram: A wiring diagram shows the electrical circuit visually. It helps technicians trace the wiring and identify any faults or open circuits that may be causing the B1259 code.
4. Solar radiation sensor inspection tool: This specialized tool is used to inspect the solar radiation sensor for physical damage or obstruction. Regular maintenance and inspection of the sensor are important to ensure accurate readings.
5. EATC Module tester: The Electronic Automatic Temperature Control (EATC) Module tester is used to diagnose and test the functionality of the EATC Module. It helps technicians determine if the module is faulty and causing the B1259 code.

How to fix Step by Step

Step 1: Understand the role of the solar radiation sensor in vehicle performance. The sensor measures sunlight intensity and provides this information to the EATC Module.

Step 2: Visually inspect the wiring harness and connectors for any signs of damage. Look for broken, bent, pushed out, or corroded pins.

Step 3: Ensure that the sensor is receiving a ground through the circuit. Check if a 5-volt reference voltage is supplied to the sensor from the EATC Module.

Step 4: If no visual issues are found, further diagnosis may be necessary. Follow appropriate repair procedures based on the diagnosis.

Step 5: Promptly address the B1259 code to prevent further damage or performance issues.

What are the Common Diagnosis Mistakes

Common diagnosis mistakes for the B1259 code should be carefully considered to ensure accurate troubleshooting and repair. Some common misdiagnoses for code B1259 include:

1. Not visually inspecting the wiring harness and connectors, which may reveal damaged components or broken, bent, pushed out, or corroded connector pins.
2. Failing to follow appropriate repair procedures based on the diagnosis, which can lead to ineffective repairs or overlooked issues.
3. Overlooking other potential causes not listed, such as faulty components or poor electrical connections in the Solar Radiation Sensor circuit.
4. Disregarding the importance of prompt diagnosis and repair, which may result in further damage or performance issues.
5. Relying solely on diagnostic trouble codes without conducting thorough inspections and tests, which can lead to incorrect conclusions.

What is the Repair Cost

The cost of repairing the B1259 code can vary based on location, vehicle make and model, and engine type. Labor costs generally range between $75 and $150 per hour at most auto repair shops.

Additional expenses may be incurred for parts and further repairs. Regular maintenance and inspections are crucial to prevent future issues with the solar radiation sensor.

Can I drive safely with this code?

Driving with the B1259 code should be avoided due to potential risks. Ignoring the code may cause further damage or performance issues.

It indicates a fault in the Solar Radiation Sensor or EATC Module, leading to engine light illumination or other symptoms.

Consult a professional for diagnosis and repairs to ensure safe driving conditions.

Wrapping Up

The B1259 code indicates a potential issue with the solar radiation sensor or the Electronic Automatic Temperature Control module in a vehicle. Ignoring this code may result in further damage or performance issues.

It is recommended to consult a professional for accurate diagnosis and repair procedures, as the cost and complexity of fixing this code may vary depending on the vehicle’s make, model, and engine type.

Promptly addressing this code is crucial for maintaining the vehicle’s functionality and safety.