B1974 code definition
The B1974 trouble code detects a passenger seat recline forward switch circuit malfunction.
What the B1974 code means
The B1974 code is a standard OBD-II trouble code that notes a circuit error in the passenger seat recline forward switch. This switch allows the angle of recline for the front passenger seatback to be adjusted forward. The switch itself is usually located on the outboard side of the seat base. If a circuit malfunction in the passenger seat recline forward switch is noticed by the body control module or the powertrain control module (PCM), then the B1974 trouble code might be triggered.
What causes the B1974 code?
There are two common problems that cause the B1974 code to be stored. The first common issue is damaged electrical components, either in the passenger seat recline forward switch, or in the power seat system. The second common issue is a failed passenger seat recline forward switch. It is also possible, though very rare, for a faulty body control module to be the cause of the B1974 trouble code.
What are the symptoms of the B1974 code?
When the B1974 trouble code is triggered, the front passenger seat will likely have problems adjusting the recline. The seatback will almost surely be incapable of reclining forward, and it will likely not be able to recline backwards, either. It is also common for the check engine soon warning light to illuminate when this code is detected.
How does a mechanic diagnose the B1974 code?
The B1974 code will be diagnosed using a standard OBD-II trouble code scanner. A trained mechanic will use the scanner to look at the freeze frame data and gather information about this code, while also checking to see if any other trouble codes are present. In the event that there are numerous codes detected, they should be assessed in the order that the scanner displays them in. The trouble codes will then be reset, the vehicle restarted, and the B1974 code checked for. If the code is no longer detected, then it is likely that an inaccurate detection, or an intermittent error is the problem.
If the B1974 code remains detected after the reset, then the technician will visually inspect all of the electrical components in the system, and replace any shorted wires, open or corroded connectors, and blown fuses. If the electrical system is in working order, then a failed passenger seat recline forward switch should be presumed.
After any replacements or repairs are made, the diagnosis should be halted so the trouble codes can again be reset, the vehicle restarted, and the B1974 code checked for. By doing this, the technician will know as soon as the problem is no longer present.
Common mistakes when diagnosing the B1974 code
The most common mistake made when diagnosing this code is the failure to follow the OBD-II trouble code diagnosis protocol. It is important that mechanics always follow the protocol step by step, to ensure efficient diagnoses and accurate repairs.
It is fairly common for damage to the electrical components to be overlooked, and fully operational passenger seat recline forward switches to be erroneously replaced as a result.
How serious is the B1974 code?
The B1974 trouble code will not keep a car from being drivable, or cause any drivability problems. However, the front passenger seat will likely not be able to adjust the recline. If the seatback is stuck folded forwards, it likely will not be usable. If the seatback is stuck in a heavily reclined position, it will not be safe for a passenger to occupy. Once the code is detected, an inspection should be scheduled.
What repairs can fix the B1974 code?
Repairs for the B1974 trouble code include:
- Replacement of wires, connectors, and fuses
- Replacement of the passenger seat recline forward switch
- In very rare cases, replacement of the body control module
Additional comments for consideration regarding the B1974 code
This code is a manufacturer specific code, which means that the definition changes by automaker. The B1974 code detects a passenger seat recline forward switch circuit error for some vehicles, but entirely different body issues for other cars. As always, the mechanic should be aware of the vehicle that is being worked on when this code is diagnosed.
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