It looks as if recalls are plaguing Honda yet again. The last time Honda had a recall this voluminous was back in 2014 when nearly 900,000 Odyssey minivans were recalled due to a faulty fuel-pump part. The Honda Odyssey made headlines again in August 2020 because of a safety feature malfunction with over 200,000 recalled. According to an article by Car Complaints published December 18, 2020, Honda has recalled an additional 770,000 models of 2018 through 2020 Accords, Accord Hybrids, and Insights.

Programming mistakes in the body control module software

As vehicles become more reliant on software, we’re likely to see more recalls related to faulty code than mechanical issues. These latest recalls by Honda exemplify this as mistakes in the programming of Body Control Module (BCM) software may cause all sorts of systems to malfunction. Such coding mistakes can interrupt communications between the modules and other components. Some of these problems include issues with the rearview camera display, defroster, windshield wipers, turn signals, and power windows.

Honda stated in a press release,

“Due to a programming flaw, a certain combination of driver actions and vehicle conditions may disrupt communication between the BCM and other components, causing illumination of several warning lights and malfunction of one or more electronic components including the rearview camera display, turn signals and windshield wipers, some potentially increasing the risk of a crash. This condition may also result in noncompliance with certain federal motor vehicle safety standards. Honda has received no reports of crashes or injuries related to this issue.”

Honda sent the faulty modules to the Kentucky-based supplier, Sumitomo Electric Wiring Systems, but didn’t find any problems. However, Honda investigators had confirmed the Controller Area Network (CAN bus) communications between particular vehicle systems were being disrupted. Investigators also looked into similar reports from Japan but eventually determined that the origin of the issues was different.

What are a BCM and CAN bus?

A BCM is also known as a body computer. It’s a general name for an electronic control unit (ECU) responsible for managing and running numerous electronic devices in a vehicle. In most vehicles, the BCM is responsible for controlling the power mirrors, power windows, rear window defrost, central locking system, immobilizer system, power mirrors, air conditioning, among other things. While its primary application is to control load drivers, it uses the CAN bus to communicate with other onboard computers in a vehicle as well.

A Controller Area Network (CAN bus) is a robust vehicle bus; a vehicle bus is a specialized internal communications network that interconnects vehicle modules and other components. Particular vehicle control requirements mandate the use of less common networking protocols. A CAN bus allows certain devices and microcontrollers to interface with each other’s software without the need for a host computer.

While data is transmitted sequentially for each device, higher priority devices are allowed to transmit their data ahead of others. Data is transmitted in frames which are received by all devices in the vehicle, including transmitting devices.

It goes without saying that interrupting communications between these components can lead to dangerous conditions. If you own any of the Honda models listed in this recall, it’s advisable to take your car to the nearest Honda service provider when the recall program starts. While some of these system issues may not be dangerous, others could potentially put you or your passengers at risk.

What you can do if your Honda vehicle is affected by this recall

There haven’t been any reports of accidents or injuries associated with the BCM issues. Nevertheless, software defects like this can result in violating several federal safety standards. Honda stated that the recall program will begin on January 18, 2021. At that time, Honda dealers will start updating the BCM software in the affected models.