General Motors has recalled over 62,000 medium-duty Chevrolet Silverado truck models. The brake pressure sensor assembly may leak hydraulic fluid into the brake pressure switch and cause an electrical short or fire, according to the National Highway Traffic Safety Administration.
The recalled vehicles include certain 2019-2024 Chevrolet Silverado 4500HD, 5500HD, and 6500HD trucks produced at various production windows between May 2018 and September 2024. Manufacturing records were used to identify the vehicles built within these timeframes.
Dealers will replace the brake pressure switch wire harness free of charge. Notification letters alerting customers of the elevated safety risk are expected to be mailed on July 28. GM will send a second letter once a remedy becomes available.
Why the Silverado's were recalled
According to the recall report, the condition is due to the rubber diaphragm seal for the pressure sensor. The automaker claims that the supplier used an unauthorized chemical during the manufacturing of the rubber diaphragm for the sensor, which can cause it to degrade over time and leak fluid. An estimated 1% of the recalled trucks are believed to have the defect.
As a result of the defect, the diaphragm may allow brake fluid to leak into the brake pressure switch and potentially seep into the electrical components of the assembly. The condition may cause a short in the brake pressure switch and the associated fuse. GM sourced the brake pressure sensors from Illinois-based Tier 1 supplier Kodiak Controls Inc.
Due to the elevated risk of fire, GM is advising Silverado customers to park outside and away from structures until the recall repairs are complete.
The current recall is also related to brake pressure sensor recall in April 2023
GM’s investigation of brake fluid leaks on Silverado trucks began nearly three years ago and its the second recall for 2019-2023 models involving the brake pressure sensor. Navistar had previously supplied a different pressure sensor that also developed fluid leaks.
In August 2022, GM opened a product investigation after a claim of a vehicle fire on a 2019 Chevrolet Silverado medium-duty vehicle. As part of this initial investigation, GM worked with Navistar to “review field data and warranty-returned brake pressure sensors,” according to the recall report.
A warranty returned sensor and harness showed signs of heat damage, leading GM to perform X-ray scans that showed brake fluid leaking past the diaphragm seal and into the brake pressure switch, as well as through the assembly’s wire harness into its fuse circuit. The condition could activate the brake assist pump when the brakes are not applied, and generate excessive heat that could result in an underhood fire in rare cases.
In February 2023, GM conducted additional analysis that found “delamination of corrosion inhibiting sealant,” which led to the brake fluid seeping past the diaphragm seal. It prompted the automaker’s Safety Field Action Decision Authority to issue a recall for over 40,000 Silverado trucks on April 6, 2023. At the time, the automaker identified 21 potentially related complaints, some of which alleged the presence of fire, smoke, or flame.
These vehicles will now require a second repair as part of the current recall.
How a whistleblower report led to the second Silverado recall
On Oct. 11, 2024, GM discovered a second incident of unintended brake pump activation on a 2023 Silverado medium-duty truck after a brand quality manager submitted a report via the automaker’s Speak Up For Safety program (the program allows employees to report any safety concerns). This truck was not included in the first recall; it used an improved brake pressure sensor designed to prevent sealant delamination. GM subsequently opened an investigation in November 2024 and found brake fluid in the vehicle’s sensor wiring harness.
On Dec. 18, 2024, GM received a third potentially related field report involving a 2021 Silverado medium-duty truck that had already been repaired under the April 2023 recall. The automaker investigation also found evidence of brake fluid in the vehicle’s brake pressure sensor wiring harness.
On March 3 of this year, GM and International Motors contracted with the Akron Rubber Development Laboratory to test the material properties of the pressure sensor diaphragm seal. The lab confirmed that the diaphragm was degrading due to the use of unauthorized chemicals by Kodiak Controls in the rubber, which reacted with the brake fluid.
Following the investigation and lab findings, GM’s investigator retrieved updated field data in April and identified one alleged fire out of 160 potentially related reports from Nov. 14, 2024, through April 30, 2025.
GM also inspected the vehicle involved in the fire and concluded it was likely related to brake fluid leaks, and on June 5, the automaker’s Safety Field Action Decision Authority authorized a safety recall. However, GM is not aware of any accidents or injuries associated with the fault.
Medium-duty Silverado trucks built before the 2019 model year use a different design and are not part of the recall. Silverado trucks equipped with a brake switch wire harness using silicone sealant to prevent brake fluid leaks are also not included in the recall.
