General Motors LLC is recalling 2015-2017 Cadillac Escalade, 2014-2018 Chevrolet Silverado, GMC Sierra, 2015-2018 Chevrolet Suburban, Tahoe, GMC Yukon vehicles. The amount of vacuum created by the vacuum pump may decrease over time. As the vacuum level drops, the brake assist decreases, increasing braking effort, extending the distance required to stop the vehicle – increasing the risk crashes on these large and heavy vehicles. GM did not disclose the source of the U.S.-made pump.
The vehicles’ vacuum assist pump is lubricated with engine oil, which flows into the pump through a filter screen. Over a period of time, oil sludge can accumulate on the filter screen, potentially restricting the flow of oil into the pump and gradually reducing the amount of vacuum pressure generated. Failure to follow recommended oil change intervals could contribute to this safety defect. These vehicles are equipped with a secondary, hydraulic power brake assist system that activates to provide power brake assist if the vacuum drops, however, as calibrated the hydraulic brake boost assist is limited at lower speeds.
The driver may feel vibration in the brake pedal or a change in the amount of pressure required to depress the brake pedal. The operator and persons inside the vehicle may hear a ticking noise coming from the engine compartment or activation of the secondary hydraulic brake assist system. In addition, a “Service Brake Assist” message will appear in the Driver Information Center within two to five minutes of vacuum level less than 10 kPA.
The chronology of the recall of bad computer programing is lengthy:
- On November 20, 2018, the National Highway Traffic Safety Administration (NHTSA) opened a preliminary evaluation (PE18-012) to investigate the subject condition. GM also conducted its own internal investigation.
- On December 13, 2018, after concluding its investigation and having reviewed the results with NHTSA, GM’s Safety & Field Action Decision Authority (SFADA) decided to extend warranty coverage for vacuum pump replacements for the subject vehicles.
- On February 7, 2019, NHTSA issued an Information Request relating to the condition. GM responded and provided the requested information on March 27, 2019.
- On July 18, 2019, NHTSA provided GM with additional field data reports. GM opened a new investigation into the issue on July 22, 2019. GM’s investigator reviewed the new data provided by NHTSA and refreshed the field data from other sources.
- On August 29, 2019, GM’s Safety & Field Action Decision Authority decided to conduct a safety recall to update affected vehicles with the new software calibration.
GM will notify owners, and dealers will reprogram the Electronic Brake Control Module, free of charge as is required by U.S. law. GM has not provided a notification schedule. Owners may contact Chevrolet customer service at 1-800-630-2438, Cadillac customer service at 1-800-458-8006 or GMC customer service at 1-800-462-8782. GM’s number for this recall is N192268490. Owners may also contact the National Highway Traffic Safety Administration Vehicle Safety Hotline at 1-888-327-4236 (TTY 1-800-424-9153) or go to www.safercar.gov.