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B1862 OBD-II Trouble Code: Climate Control A/C Lock Sensor Failure

diagnostic check engine light

B1862 code definition

The B1862 trouble code detects a malfunction with the climate control A/C lock sensor.

What the B1862 code means

The B1862 code is a standard OBD-II trouble code that notes a climate control A/C lock sensor failure. The lock sensor (also known as an A/C speed sensor) is responsible for measuring the revolutions per minute (RPM) of the air conditioner compressor. The compressor RPM is then compared to the engine RPM, to make sure that they are both within a similar range. If the climate control module, body control module, or powertrain control module (PCM) fail to receive a signal from the A/C lock sensor, or note that the engine and compressor speed are not similar, then the B1862 code may be stored.

What causes the B1862 code?

Two issues can commonly cause the B1862 trouble code: a defective A/C lock sensor, and damaged electrical components (such as wires, connectors, and fuses) in the climate control system. While very rare, it is also possible that a malfunctioning PCM, body control module, or climate control module is responsible for this code.

What are the symptoms of the B1862 code?

When the B1862 trouble code is stored, the air conditioning system will most likely not work. Sometimes the air conditioner will fail completely, while other times it will run for five seconds, and then shut off. The A/C light on the climate controls may also flash.

How does a mechanic diagnose the B1862 code?

The B1862 code will be diagnosed using a standard OBD-II trouble code scanner. A trustworthy technician can assess the code using the freeze frame data from the scanner, and can also check for additional trouble codes that may be present. If there are numerous codes detected, the mechanic will address them in the order in which they are displayed. The technician will then reset the trouble codes, restart the vehicle, and see if the B1862 code is still detected. If not, then it was likely incorrectly detected, or the result of an intermittent error.

If the code remains, then the mechanic should begin by visually inspecting the electrical components in the system. Any blown fuses, corroded or open connectors, and shorted wires will need to be replaced. The A/C lock sensor will then be inspected. If the sensor is defective, then the entire A/C compressor may need to be replaced, depending on the vehicle.

After any components are replaced, the trouble codes will again be reset, the vehicle restarted, and the B1862 code checked for. This allows the mechanic to be alerted as soon as the issue is fully resolved.

Common mistakes when diagnosing the B1862 code

The most frequently made mistake when diagnosing this code comes from a failure to properly follow the OBD-II trouble code diagnosis protocol. It’s important that technicians always follow the protocol, as it helps avoid erroneous repairs, and ensures accurate and efficient inspections. A/C lock sensors and compressors are often inaccurately replaced when electrical components are overlooked.

How serious is the B1862 code?

The B1862 code will likely keep the air conditioning system from operating. As with all trouble codes, an inspection should be scheduled as soon as the code is detected.

What repairs can fix the B1862 code?

Repairs for the B1862 code include:

Additional comments for consideration regarding the B1862 code

The B1862 code is a manufacturer specific trouble code, which means that the definition varies depending on the automaker. This code signals an A/C lock sensor failure in some vehicles, but detects a different problem in other makes. The mechanic should always note what vehicle is being worked on when diagnosing the B1862 code.

Need help with a B1862 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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