GM bulletin PIT5509K
What it saysThis Preliminary Information communication provides information to the technician on how to diagnose and repair vehicle that may have a "Check Trailer Wiring" or "Service Trailer Brake System? message on the Driver… NHTSA’s full summary ↓
GM filed this with NHTSA as a service bulletin dated May 22, 2023, received Jun 13, 2023, about the electrical system. It names 67 model years across Chevrolet, GMC and Cadillac (2016–2024). A service bulletin is not a safety recall: it is the manufacturer telling its dealers how to diagnose or repair a condition, and whether the work is paid for depends on the warranty in force. Quoting the number at a service desk can save a diagnosis.
One page for every brand it was filed under. Each brand’s bulletins: Chevrolet · GMC · Cadillac.
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What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationThis Preliminary Information communication provides information to the technician on how to diagnose and repair vehicle that may have a "Check Trailer Wiring" or "Service Trailer Brake System? message on the Driver Information Center when a trailer is connected to the vehicle. Diagnostic Trouble Code C1114 set in the Chassis Control Module. Chassis Control Module has to determine the type of trailer brake system that is being used. The Chassis Control Module can be sensitive to a variety of trailer wiring issues. The technician will need to make a trailer tester using Electric Trailer Brake Magnets and 7-way trailer connector to determine if it is a vehicle or trailer issue. If the concern is not duplicated with the tester installed, the vehicle is operating correctly and the focus should be on the trailer wiring or 7 way connector.
Trouble codes it names: C1114
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| PIT5509K | Service bulletin | May 22, 2023 | 10237677 | not found |
The summary is NHTSA’s abstract of the document, as filed under 49 CFR 579.5. One communication is usually filed as several documents — the bulletin, a dealer notice, an owner letter — and the number on any of them finds this page. A PDF link is shown only once NHTSA’s own server has been seen to serve that document; the rest are checked over the following nights. Quote the number at a service desk; it is what the dealer’s system is keyed on.
Model years it names
Source: as the manufacturer filed themChevrolet 36 model years
GMC 27 model years
and 19 more on this site: 2016 GMC Canyon, 2023 GMC Sierra, 2022 GMC Sierra, 2021 GMC Sierra, 2019 GMC Sierra, 2018 GMC Sierra, 2017 GMC Sierra, 2020 GMC Sierra 2500HD, 2016 GMC Sierra 2500HD, 2024 GMC Sierra 3500HD, 2024 GMC Yukon, 2023 GMC Yukon, 2022 GMC Yukon, 2021 GMC Yukon, 2020 GMC Yukon, 2019 GMC Yukon, 2018 GMC Yukon, 2017 GMC Yukon, 2016 GMC Yukon.
Cadillac 4 model years
A vehicle page’s bulletin list shows the newest few communications filed against that model year; the count there is every one.
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What owners reported
Source: NHTSA complaint databaseOwners of the 67 model years this bulletin names have filed 16,086 complaints with NHTSA since 2015. 2,461 of them name Electrical System, Air Bags — the same broad component group this bulletin is filed under. NHTSA groups complaints coarsely, so that means the same area of the vehicle, not necessarily the same fault.
On the 2019 Chevrolet Silverado, the 72 owners who gave an odometer reading for Electrical System reported it at a median of 11,750 miles. That figure is one model year’s, not the whole range this bulletin covers — medians from different model years are not averaged.
There are crackling sounds coming from the wheel when going over humps. no power while driving or changing lanes it's worst when the ac is on, was burning gas like crazy, and shakes at 65 mph., the gas while escalating makes a clicking noise like 2 iron knocking together, and the dashboard including the radio, and telephone screens goes…
2021 Chevrolet Colorado · Electrical System · filed with NHTSA Jul 25, 2023
My doors lock with the car with the keys in the car, my kids were in my car and I got locked out with my keys in it, there was a battery replacement done when I took my car in for a recall notice a month ago (maybe 2 months), also the lock button works but when I push the middle button it will not auto start , when I push the button on…
2018 Chevrolet Suburban · Electrical System · filed with NHTSA May 11, 2021
The contact owns a 2024 GMC Sierra 3500. The contact stated while driving at approximately 60 MPH and towing a Forest River Riverstone Legacy 5th Wheel trailer, the brake pedal was depressed to slow for oncoming stopped traffic; however, the vehicle failed to respond as needed with the “Service Trailer Brake” warning light illuminated.
2024 GMC Sierra 3500HD · Electrical System · filed with NHTSA Jul 9, 2025
A complaint is one owner’s account, not a defect finding, and a bulletin is not a recall. Nothing here says this bulletin was issued because of these complaints, or that the repair it describes fixed them. Complaint files on this site begin in 2015.
More bulletins about the electrical system
Source: same model, same component group343 other manufacturer communications filed against these GM models under the same component group (electrical system), newest first. The eight newest are listed; the rest are on the Chevrolet list.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| N252529080 | Service campaign | Apr 1, 2026 | Service Update. Certain vehicles listed above may be missing a high voltage header plug on the RESS battery pack drive motor connector. Dea… |
| N252515590 | Service campaign | Jan 27, 2026 | Certain vehicles listed above, may have a condition in which the body-to-chassis ground strap may be corroded. Dealers will replace the grou… |
| 24-NA-166 | Service bulletin | Nov 7, 2025 | This technical bulletin provides repair information to correct a customer concern of DTC C1171 C1172 C1173 C1174 Tire Pressure Monitor Senso… |
| 18-NA-180 | Service bulletin | Sep 4, 2025 | This Warranty Administration service bulletin provides Lithium-Ion battery Exchange Process and Transaction Submission information. |
| 25-NA-021 | Service bulletin | Jun 7, 2025 | This technical bulletin provides repair information to correct a customer concern of Radio Software Update W23E-178.1.2-M174-SQBR6-93.3. |
| 22-NA-083 | Service bulletin | May 17, 2025 | This service bulletin provides Requirements for Replacement of the Dual Mode Cord Set Under Warranty. |
| 23-NA-151 | Service bulletin | May 16, 2025 | This service bulletin and criteria within are to determine the internal state of the High Voltage Battery and core return shipping method. |
| PIE0753I | Service bulletin | May 15, 2025 | This engineering information (EI) will assist GM to recover a small number of electric vehicle battery packs from customer-owned vehicles in… |
Quote the number at the service desk. It is what the dealer’s system is keyed on.
Every manufacturer communication NHTSA holds for Chevrolet, GMC and Cadillac, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is GM PIT5509K a recall?
No. A service bulletin is a manufacturer communication filed with NHTSA under 49 CFR 579.5; a safety recall carries an NHTSA campaign number (two digits, a letter, six digits) and a federal duty to repair for free. Check the vehicle’s recalls by VIN at nhtsa.gov/recalls, or on its page here.
Is the PIT5509K repair free?
Not automatically. A service bulletin describes how to diagnose or repair a condition; who pays depends on the warranty in force, any extension, and the dealer. Quoting the number can save a diagnosis either way.
Which vehicles does PIT5509K cover?
The manufacturer filed it against 67 model years across 3 brands (Chevrolet, GMC and Cadillac): 2024 Cadillac Escalade, 2023 Cadillac Escalade, 2022 Cadillac Escalade, 2021 Cadillac Escalade, 2024 Chevrolet Colorado, 2023 Chevrolet Colorado and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.