B1316 - In Car Temperature Sensor Open Circuit

Introduction:

The B1316 diagnostic trouble code (DTC) indicates an issue with the in-car temperature sensor, specifically an open circuit. This sensor plays a crucial role in the automatic climate control system, ensuring the vehicle's interior maintains the desired temperature. When the sensor circuit is open, the climate control system may malfunction, leading to discomfort for the occupants and potential inefficiencies in the HVAC system's operation.

Table: B1316 - In Car Temperature Sensor Open Circuit Details

Detailed Explanations:

Sensor Function:

The in-car temperature sensor, also known as the interior temperature sensor, is a thermistor (a resistor whose resistance changes with temperature). This sensor is responsible for measuring the temperature inside the vehicle's cabin. The sensor sends this temperature data to the HVAC (Heating, Ventilation, and Air Conditioning) control module. This information is crucial for the automatic climate control system to regulate the air conditioning, heating, and ventilation to maintain the desired temperature set by the driver or passengers.

Code Definition:

The B1316 DTC specifically indicates an "Open Circuit" in the electrical circuit of the in-car temperature sensor. An open circuit means that the electrical path between the sensor and the HVAC control module is broken, preventing the sensor's signal from reaching the module. This interruption can be caused by a variety of factors, such as a broken wire, a corroded connector, or a faulty sensor.

Symptoms:

Several symptoms can indicate a B1316 code and a malfunctioning in-car temperature sensor:

• Inaccurate climate control: The most common symptom is the inability of the climate control system to maintain the set temperature. The system may blow hot air when cold air is desired, or vice versa.
• System blowing only hot or cold air regardless of settings: The HVAC system might be stuck in either heating or cooling mode, ignoring the temperature settings.
• HVAC system not responding to temperature adjustments: Changes made to the temperature settings on the climate control panel have no effect on the actual air temperature.
• DTC B1316 is stored: The presence of the B1316 code itself is a direct indicator of the problem.

Possible Causes:

The B1316 code can be triggered by several underlying issues:

• Faulty In-Car Temperature Sensor: The sensor itself might be defective. Over time, the thermistor inside the sensor can fail, leading to an inaccurate or nonexistent signal.
• Open Circuit in Wiring: A break in the wiring between the sensor and the HVAC control module is a common cause. This can occur due to physical damage, corrosion, or stress on the wires.
• Poor Connection: Corroded or loose connectors at the sensor or the control module can disrupt the electrical connection. Corrosion can build up over time, especially in humid environments.
• Damaged Wiring: Wires can be cut, frayed, or shorted to ground. This can happen due to accidents, wear and tear, or rodent activity.
• HVAC Control Module Failure: (Less Likely) Although less common, the HVAC control module itself could be faulty, preventing it from reading the sensor signal. This is usually diagnosed after ruling out other potential causes.
• Rodent Damage: Rodents often chew on vehicle wiring, especially if the vehicle is parked for extended periods.
• Aftermarket Accessories: Poorly installed aftermarket accessories, such as remote starters or alarms, can sometimes interfere with the sensor circuit.

Diagnostic Steps:

A systematic approach is crucial for diagnosing the root cause of the B1316 code:

1. Visual Inspection: Begin by visually inspecting the sensor and its wiring harness for any obvious signs of damage, such as cuts, frays, or corrosion. Pay close attention to the area around the sensor and along the wiring path.
2. Check Connector: Inspect the connector at the sensor and the HVAC control module for corrosion, loose connections, or damaged pins. Use a connector cleaner to remove any corrosion. Ensure the connector is securely attached.
3. Wiring Test: Use a multimeter to perform a continuity test on the wiring between the sensor and the HVAC control module. This test verifies that there is an unbroken electrical path. Refer to the vehicle's wiring diagram to identify the correct wires to test.
4. Sensor Resistance Test: Measure the resistance of the sensor using a multimeter and compare it to the manufacturer's specifications. The resistance value should vary with temperature. If the resistance is significantly different from the specified range or is infinite (indicating an open circuit within the sensor), the sensor is likely faulty.
5. Voltage Test: Check for proper voltage supply to the sensor. Use a multimeter to measure the voltage at the sensor connector. Refer to the vehicle's wiring diagram for the correct voltage specification.
6. HVAC Control Module Test: (If other tests fail) If all other tests have been performed and the problem persists, the HVAC control module might be faulty. This requires specialized diagnostic equipment and expertise. Check the input circuit on the HVAC control module for proper sensor signal.

Tools Required:

• Scan Tool (capable of reading OBDII codes): To retrieve and clear the B1316 code.
• Multimeter: For testing wiring continuity, sensor resistance, and voltage.
• Wiring diagrams for the vehicle's HVAC system: Essential for identifying the correct wires and components.
• Basic hand tools (screwdrivers, pliers, wire strippers): For accessing and working on the sensor and wiring.
• Connector cleaner: To remove corrosion from electrical connectors.

Common Replacement Parts:

• In-Car Temperature Sensor: The most common replacement part if the sensor is found to be faulty.
• Wiring connectors: To replace corroded or damaged connectors.
• Wiring repair kit: For repairing damaged wires.

Related Codes:

• B1315 (In Car Temperature Sensor Short to Ground): Indicates that the sensor circuit is shorted to ground.
• B1317 (In Car Temperature Sensor Short to Battery): Indicates that the sensor circuit is shorted to the vehicle's battery voltage.
• Other HVAC system related DTCs: May indicate other issues with the climate control system.

Severity Level:

The severity level of the B1316 code is considered moderate. While it doesn't directly affect vehicle safety, it significantly impacts passenger comfort. An inaccurate climate control system can make driving uncomfortable, especially in extreme weather conditions. Furthermore, it can lead to inefficient HVAC operation, potentially increasing fuel consumption.

Repair Costs:

Repair costs vary depending on the cause of the problem:

• Sensor replacement: Typically ranges from $50 to $200 (parts and labor).
• Wiring repairs: Can range from $50 to $300 or more, depending on the complexity of the wiring damage.
• HVAC control module replacement: Can be significantly more expensive, potentially costing several hundred dollars or more.

Location of Sensor:

The location of the in-car temperature sensor varies depending on the vehicle make and model. It is typically located near the steering column, in the dashboard, or integrated into the overhead console. Consult the vehicle's service manual for the exact location. Some vehicles have a small vent or grille near the sensor to allow air to circulate around it.

Frequently Asked Questions:

• What does B1316 code mean? The B1316 code means that the vehicle's computer has detected an open circuit in the in-car temperature sensor circuit, indicating a break in the electrical path.

• Can I drive with a B1316 code? Yes, you can drive with a B1316 code, but your climate control system may not function correctly, leading to discomfort.

• How do I fix a B1316 code? Fixing a B1316 code involves diagnosing the cause of the open circuit (faulty sensor, damaged wiring, etc.) and then repairing or replacing the affected component.

• Is B1316 an expensive fix? The cost of fixing a B1316 code depends on the cause, but sensor and wiring repairs are generally moderately priced, while control module replacements can be more expensive.

• Where is the in-car temperature sensor located? The sensor's location varies, but it is commonly found near the steering column, in the dashboard, or integrated into the overhead console.

Conclusion:

The B1316 DTC indicates an open circuit in the in-car temperature sensor, leading to potential climate control system malfunctions. Thorough diagnosis involving visual inspection, wiring tests, and sensor checks is crucial for identifying and resolving the root cause. Repairing the open circuit will restore proper climate control functionality and ensure passenger comfort.