B1242 code definition
The B1242 trouble code detects an error with the air flow recirculation door driver.
What the B1242 code means
The B1242 code is a generic OBD-II trouble code that notes a circuit error with the air flow recirculation door driver. The air flow recirculation system is a crucial part of the heating, ventilation, and air conditioning (HVAC) system, as it helps recirculate air through the vehicle’s cabin. When the body control module or the powertrain control module (PCM) notes that the air control recirculation door driver is malfunctioning, then the B1242 code will be detected.
What causes the B1242 code?
The B1242 code can be caused by a few different things:
- Defective air inlet door actuator motor
- Damaged wires, connectors, or fuses in the HVAC module
- Short circuit in the control lines
- Faulty ground wire
- Jammed air flow recirculation door
- Defective HVAC module
- In rare cases, defective PCM, body control module, or climate control module
What are the symptoms of the B1242 code?
The B1242 trouble code will likely be accompanied by the check engine soon Warning Light illuminating on the vehicle’s gauge cluster. There will likely also be problems with the climate control system, such as an inability to recirculate, or improper air temperature.
How does a mechanic diagnose the B1242 code?
The B1242 code will be diagnosed using a standard OBD-II trouble code scanner. A certified mechanic will use the scanner to view the freeze frame data and assess the B1242 code. The scanner will also be used to check for the presence of additional trouble codes. If the technician notices that there are multiple codes present, then they will need to be addressed in the order in which they are received. The mechanic will then reset the trouble codes, restart the vehicle, and check to see if the code is still present. If not, then the code was likely the cause of an intermittent error, or perhaps an inaccurate detection.
If the B1242 code remains detected, then the mechanic will begin with a visual inspection of all of the electrical components in the system. Any blown fuses, short wires, or open or corroded connectors will need to be replaced. The air flow recirculation door should then be inspected to make sure it is not jammed, and then the ground wire will be checked. If the issue is unresolved, then the problem is likely a faulty air inlet door actuator motor.
If the air inlet door actuator motor is not the problem, then the circuits and the HVAC system will need to be more thoroughly inspected.
After any component is replaced, the mechanic will need to reset the trouble codes, restart the vehicle, and again look for the presence of the B1242 code. By doing this, the mechanic will know as soon as the problem has been fixed.
Common mistakes when diagnosing the B1242 code
The most frequently made error when diagnosing the B1242 code comes from a failure to properly follow the OBD-II trouble code diagnosis protocol. It is very important that the mechanic abide by the protocol at all times, to help ensure inspections and repairs that are thorough and efficient.
It is fairly common for electrical malfunctions to be overlooked when diagnosing the B1242 code, which can lead to unnecessary repairs.
How serious is the B1242 code?
A vehicle with the B1242 trouble code will still be drivable, though the climate control system will likely be compromised. The vehicle should be inspected and repaired sooner rather than later.
What repairs can fix the B1242 code?
Repairs for the B1242 trouble code are:
- Air inlet door actuator motor replacement
- Replacement of electrical components
- Ground wire replacement
- Replacement of circuits in the control line
- Removing the jam that is restricting the air flow recirculation door
- In rare cases, replacing the HVAC module, PCM, climate control module, or body control module
Additional comments for consideration regarding the B1242 code
While the B1242 signals an air flow recirculation door driver circuit failure in many vehicles, the code can stand for a different issue in some makes and models.
Need help with a B1242 code?
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This article originally appeared on YourMechanic.com as B1242 OBD-II Trouble Code: Air Flow Recirculation Door Driver Circuit Failure and was authored by Brady Klopfer.