Brake Pedal Moves Or Self Applies At Full Turns (PIT3665M)
Publication date: 2023-08-18Reference number: PIT3665M
Supersedes refnos: PIT3665, PIT3665A, PIT3665B, PIT3665C, PIT3665D, PIT3665E, PIT3665F, PIT3665G, PIT3665H, PIT3665I, PIT3665J, PIT3665K, PIT3665L
BRAKE PEDAL MOVES OR SELF APPLIES AT FULL TURNS
TECHNICAL SERVICE BULLETIN
Reference Number(s): 23-NA-144, Date of Issue:
Aug 18, 2023
| Supercedes: | This bulletin replaces PIT3665M. Please discard PIT3665M. |
SERVICE INFORMATION
| Brand: | Model: | Model Year: | VIN: | Engine: | Transmission: | ||
|---|---|---|---|---|---|---|---|
| from | to | from | to | ||||
| Cadillac | Escalade Models | 2001 | 2004 | - | - | All | All |
| Chevrolet | Avalanche | 2002 | |||||
| Tahoe | 2001 | ||||||
| Suburban | |||||||
| Suburban 3500HD | 2016 | 2019 | |||||
| Express | 1998 | 2024 | |||||
| Silverado 2500/3500HD | |||||||
| Astro Van | 2005 | ||||||
| GMC | Savana | 2024 | |||||
| Sierra 2500/3500HD | |||||||
| Yukon | 2001 | 2004 | |||||
| Safari | 1998 | 2005 | |||||
| Hummer | H2 | 2003 | 2007 | ||||
| Involved Region or Country | Middle East, Israel, and North America |
| Additional Options (RPOs) | Equipped With Hydro-Boost Brake System |
| Condition | On vehicles with a Hydro-Boost System, customers may notice during full lock turns or near full lock turns that the brake pedal will move down or self apply. |
| Cause | The cause of the condition may be the internal dump valve of the hydro-boost not seating properly due to contamination in the steering system. Contamination can come from steering pump damage when the steering wheel is being held at the stops for an extended period, causing it to overheat or introduced by adding contaminated power steering fluid. |
SERVICE PROCEDURE
IMPORTANT:
Service agents must comply with all International, Federal, State, Provincial, and/or Local laws applicable to the activities it performs under this bulletin, including but not limited to handling, deploying, preparing, classifying, packaging, marking, labeling, and shipping dangerous goods. In the event of a conflict between the procedures set forth in this bulletin and the laws that apply to your dealership, you must follow those applicable laws.
The Hydro-Boost System is not serviceable and must be replaced. Refer to the proper Power Brake Booster Replacement procedure within SI.
IMPORTANT:
- Before replacement of the Hydro-Boost System, the entire steering system (including power steering pump, lines, cooler, and gear box) must be flushed to avoid a reoccurrence.
- If the vehicle has been in with the same concern within 20k miles (32,000 km) of previous repair then it is recommended that the entire steering system (including power steering pump, lines, cooler, and gear box) be replaced.
- For vehicles no longer under warranty, inform the customer that replacing the Hydro-Boost unit only, could possibly result in a shorter lifespan of the unit itself and that the customer may choose to replace all other steering system components if desired, at their own expense.
PARTS INFORMATION
Use the VIN and refer to the GM Electronic Parts Catalog (EPC) to determine the proper part number to order.
WARRANTY INFORMATION
For vehicles repaired under warranty, use:
| Labor Operation | Description | Labor Time |
|---|---|---|
| 2441730 | Power Brake Booster Replacement | Use Published Labor Operation Time |
SERVICE INFORMATION
| Version | 1 |
| Modified | Released August 17, 2023 |