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B1968 OBD-II Trouble Code: AC Water Pump Detection Circuit Failure

diagnostic check engine light

B1968 code definition

The B1968 trouble code detects an AC water pump detection circuit malfunction.

What the B1968 code means

The B1968 code is a generic OBD-II trouble code that notes a circuit error in the AC water pump detection system. The AC water pump is part of the climate control system, and is used to help adjust the air temperature that enters the vehicle’s cabin. The detection system monitors the water pump and relays information to the climate control unit, so that the temperature can be properly adjusted. If the climate control module, body control module, or powertrain control module (PCM) receive an abnormal voltage reading from the AC water pump detection system, then the B1968 trouble code may be stored.

What causes the B1968 code?

The B1968 code is most commonly caused by damaged electrical components in the AC system. Any wires that are shorted or open, connectors that are loose or corroded, or fuses that are blown can trigger the code. It is also fairly common for the code to be caused by a faulty detection sensor or a failed AC water pump. While rare, a malfunctioning climate control module can also cause the code to be stored.

What are the symptoms of the B1968 code?

The B1968 trouble code is usually accompanied by an illuminated check engine soon warning lighton the dashboard, and possibly a flashing AC light on the center console climate controls. It is likely that the climate control system will not function properly, which may result in a lack of hot air, erratic temperature from both the heater and the air conditioner, and a failed defroster.

How does a mechanic diagnose the B1968 code?

The B1968 trouble code will be diagnosed using a standard OBD-II trouble code scanner. A trustworthy technician will use the scanner to look at the freeze frame data and gather information about the code. The mechanic will also use the scanner to see if any additional trouble codes are present, as codes need to be addressed in the order that they appear in. The codes will then be reset, the vehicle restarted, and the B1968 code checked for. If the code is no longer present after this reset, then an erroneous detection, or an intermittent error are the most likely problems.

If the code is still present, then the mechanic will visually inspect all of the electrical components in the climate control system. Any damaged or otherwise compromised wires, fuses, or connectors will need to be replaced. The AC water pump and detection system should then be inspected.

After any components are replaced, the trouble codes will once again need to be reset, the vehicle again restarted, and the B1968 code checked for once more. This will allow the mechanic to know as soon as the problem has been identified and resolved.

Common mistakes when diagnosing the B1968 code

The most common error when diagnosing the B1968 code comes from not following the OBD-II trouble code diagnosis protocol. It is important that mechanics always follow the protocol step by step, to make sure that all diagnoses are thorough and accurate.

Properly working AC water pumps are often erroneously replaced because damaged electrical components are not repaired.

How serious is the B1968 code?

The B1968 trouble code will not keep a car from being drivable, or even result in any drivability concerns. However, the climate control system will likely act erratically, or even not at all, which can be a hassle, especially when driving in harsh weather. As with all trouble codes, the B1968 code should be addressed as soon as possible after being detected.

What repairs can fix the B1968 code?

Possible repairs for the B1968 trouble code include:

Additional comments for consideration regarding the B1968 code

The B1968 code is a manufacturer specific trouble code. Manufacturer specific codes are codes that have varying definitions depending on the automaker. So while this code signals an AC water pump detection circuit failure for some cars, it can detect a very different body problem in other vehicles. Mechanics should always be aware of the make and model that they are inspecting when diagnosing this trouble code.

Need help with a B1968 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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