GM bulletin PIT5509L
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 Sep 11, 2024, about the service brakes. It names 66 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 |
|---|---|---|---|---|
| PIT5509L | Service bulletin | Sep 11, 2024 | 11007691 | PDF, 57 KB |
What the document itself lists
Part the bulletin names
| Part number | Description | Qty | Find it |
|---|---|---|---|
| 23404450 | — | — |
Read by machine from the document NHTSA serves (9 pages), read Sep 30, 2026. A part number is shown only where it matches GM’s own catalogue shape, an operation only with its code and time, and a description only where the reader got it whole; anything it could not settle is left out, and the PDF is the record. Times are the manufacturer’s warranty allowances, not a quote. Listings and prices on eBay Motors are the seller’s.
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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 35 model years
GMC 27 model years
and 19 more on this site: 2016 GMC Canyon, 2024 GMC Sierra, 2023 GMC Sierra, 2022 GMC Sierra, 2021 GMC Sierra, 2020 GMC Sierra, 2019 GMC Sierra, 2018 GMC Sierra, 2017 GMC Sierra, 2016 GMC Sierra, 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 66 model years this bulletin names have filed 18,828 complaints with NHTSA since 2015. 2,230 of them name Service Brakes — 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 2016 Chevrolet Silverado, the 180 owners who gave an odometer reading for Service Brakes reported it at a median of 50,000 miles. That figure is one model year’s, not the whole range this bulletin covers — medians from different model years are not averaged.
Bought new and there was a brake pad sensor message immediately that we took it to the dealer several times for and nothing was done other than clearing the code and giving it back. Was in accident 1/24 and it was found that there was a frayed/damaged wire in the break module and break pad sensor that I feel could have led to the accident
2023 Chevrolet Tahoe · Service Brakes · filed with NHTSA Apr 2, 2024
After the latest update from the Dealer, the integrated trailer brake module no longer shows an output of how much power it's applying to the trailer brake system. It just stays blank. I can tell that the brakes actually are being applied, however not having indication of them being applied and how much pressure is applied is concerning
2024 GMC Sierra · Service Brakes · filed with NHTSA Jun 2, 2026
Some time when I brake, the car do not stop immediately is slighting before stopping by short brake, and backward driving the car do not want to stop and after, driving again regularly is fine I had the car in service they say the car is fine...........i tough maybe I have to renew the brake but no brake are fine this problem began on…
2016 Chevrolet Suburban · Service Brakes · filed with NHTSA Feb 18, 2018
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 service brakes
Source: same model, same component group38 other manufacturer communications filed against these GM models under the same component group (service brakes), newest first. The eight newest are listed; the rest are on the Chevrolet list.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| N252521980-01 | Service campaign | Oct 31, 2025 | Certain vehicles listed above, may have a condition in which the Brake System Control Module does not have the latest software. Dealers are… |
| N252521980 | Service campaign | Oct 22, 2025 | Certain vehicles, may have a condition in which the Brake System Control Module does not have the latest software. Dealers are to reprogram… |
| 23-NA-201 | Service bulletin | Sep 6, 2025 | This service bulletin advises the technician of a possible loose ground that may be causing customer concerns of Loss of Steering Assist and… |
| 25-NA-264 | Service bulletin | Sep 3, 2025 | This informational bulletin provides information on Automated Brake Bleed and/or Brake Hydraulic Test procedure fails when attempting to per… |
| 25-NA-064 | Service bulletin | Mar 20, 2025 | This informational bulletin provides information on the brake system warning lamp illuminated on driver information center (DIC), brake peda… |
| PIT6347A | Service bulletin | Mar 11, 2025 | This Preliminary information communicates an issue with ABS SES MIL / Service Brake System / Service StabiliTrak / BSCM DTC P0606 P0562 and… |
| PIT6347 | Service bulletin | Feb 25, 2025 | This Preliminary information communicates an issue with ABS SES MIL / Service Brake System / Service StabiliTrak / BSCM DTC P0606 P0562 and… |
| 24-NA-048 | Service bulletin | Feb 6, 2025 | This engineering informational bulletin is requesting information from technicians to perform the check list provided and contact the engine… |
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 PIT5509L 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 PIT5509L 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 PIT5509L cover?
The manufacturer filed it against 66 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.