General Motors has issued a technical service bulletin for certain examples of the 2021 model-year Chevy Tahoe and Suburban and GMC Yukon and Yukon XL full-size SUVs over an issue related to the auxiliary heater coolant pump hose.
The problem: affected vehicles were built with a faulty horizontal hose for the auxiliary heater coolant pump. The clamp may not be properly aligned and positioned on the hose, or the hose is rolled over on the pump port. This GM service bulletin includes vehicles in dealer inventory and customer vehicles that return to the dealership for any reason. The bulletin will expire at the end of the involved vehicle warranty period. Involved GM SUVs come with a three-year/36,000-mile (whichever comes first) basic warranty coverage.
The hazards: vehicles with this issue can develop a significant fluid leak early in the vehicle’s life. As the coolant level drops, a Low Coolant Warning or potential for engine overheat with DIC message will be relayed to the driver via the instrument panel.
The fix: dealers are to inspect both the vertical and horizontal hoses for the auxiliary coolant pump and repair them as needed.
Affected components: horizontal hose for auxiliary heater coolant pump.
- General Motors TSB number: A202321230
- Chevy customer service number: 1-800-222-1020
- GMC customer service number: 1-800-462-8782
GM also issued a TSB for certain examples of the 2021 Tahoe, Suburban, Yukon and Yukon XL last month over an issue related to the electrical connection to the seat-mounted inboard airbag system.