The owners of 40,428 Chevrolet Silverado 4500HD, 5500HD, and 6500HD trucks equipped with the 6.6-liter Duramax diesel engine are being advised to park their trucks outside until a recall can fix an issue within their vehicle’s braking system.
General Motors first opened an investigation into the issue in August 2022, after reports of a vehicle fire reached it. It attempted to recreate the issue, conducted X-ray scans, and performed laboratory chemical analysis of the components to determine the root cause of the issue.
It determined that the brake fluid was seeping past the diaphragm seal in the brake pressure sensor assembly, and into the brake pressure switch through the wire harness. That eventually led to the brake pump’s fuse circuit, which can generate excessive heat and result in a fire, according to documents filed with the National Highway Traffic Safety Administration (NHTSA).
Read: Over Half A Million Kia And Hyundai Owners Told To Park Outside Over Fire Risk
Naturally, that’s an issue for safety, because fires are dangerous. However, what’s more alarming is that Chevrolet says that an underhood fire could occur even when the vehicle is off and unattended.
Fortunately, it isn’t aware of any crashes or injuries being caused by the issue. Despite that, Chevrolet is aware of 21 potentially related complaints, including legal claims. A total of 11 of those allege that fire, smoke, or flames resulted from the fault.
In its investigation, GM found that the root cause of the leak is a zinc nickel plating and sealant that were used to protect the pressure sensor assembly from corrosion. These may cause delamination of the sealant, which would result in small fragment of it finding their way under the diaphragm, ultimately allowing brake fluid through, too.
The automaker has, therefore, launched a recall campaign, and will start getting in touch with owners on May 29. GM plans to replace the master cylinder pressure sensor of affected vehicles, and will also inspect the associated wiring harness to see if it needs replacing, too.
