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Service bulletins for the 2020 Peterbilt 389

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

57 on file from NHTSA, as of 2026-10-19.

Warranty extensions
CE0372026-05-06. FUEL/PROPULSION SYSTEM. KW & PB DEF Quality Sensor part number Q21-6127-001 for Cummins X15 engines has been added to this warranty policy.
7-7002024-11-05. POWER TRAIN; ENGINE. 7/700 Service Agreement - Letter Only.

A warranty extension may pay for a repair after the basic warranty has ended. Read the document for which vehicles and which repair it covers.

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Bulletins, newest first
42-0702026-10-17. Service bulletin. UNKNOWN OR OTHER. Due to supplier constraints, an authorized aftermarket surge tank has been made available.
P0012026-09-29. Service bulletin. ENGINE. "Kenworth: Dealers should check the chassis list and SIR weekly for VIN changes. 2 chassis added to the chassis list. Peterbilt: Dealers should check the chassis list and SIR weekly for VIN changes. 10 chassis added to the chassis list."
E3432026-09-23. Service bulletin. ENGINE. An exhaust manifold slip joint seal kit is now available for EPA 2017-2024 PACCAR MX-13 engines.
43-0882026-08-20. Service bulletin. ENGINE. The procedure has been updated to include additional steps for verifying the software level on the vehicle electronic control unit (VECU2) and digital display (DD). Steps have also been added to the PACCAR Common Rail Injection 2 (PCI2) software verification.
E3112026-07-30. Service bulletin. ENGINE. 105 chassis have been removed from the chassis list and unflagged in PRWS due to expiration of applicable warranty coverage. Total chassis population is 732.
43-0882026-07-23. Service bulletin. ENGINE. This optional software update is now available for chassis equipped with EMY 2021B-2023 PACCAR MX-11 and MX-13 engines. This update provides customers with additional time to service their trucks before a DEF-related derate occurs. The software is being offered to customers in alignment with recently updated regulatory agency guidance.
E3112026-07-21. Service bulletin. ENGINE. The Condition, Chassis Affected, Service Action, Warranty, and Procedure sections have been updated to include the latest prognostics bulletin verbiage.
43-0882026-07-21. Service bulletin. ENGINE. "The software is not yet available. The bulletin will be updated when more information is available."
43-0882026-07-02. Service bulletin. ENGINE. "An optional software update will be available on 07/06/2026 for chassis equipped with EMY 2021B-2023PACCAR MX-11 and MX-13 engines. This update provides customers with additional time to service theirtrucks before a DEF-related derate occurs. The software is being offered to customers in alignment withrecently updated regulatory agency guidance."
45-0702026-05-06. Service bulletin. ENGINE. The attached procedures document has been updated with more detail and explanations. This is not a stand-alone procedure. Cummins Quickserve troubleshooting will specify the use of these procedures while troubleshooting specific fault codes.
CE0372026-05-06. Warranty extension. FUEL/PROPULSION SYSTEM. KW & PB DEF Quality Sensor part number Q21-6127-001 for Cummins X15 engines has been added to this warranty policy.
E3262026-05-06. Emissions. ENGINE; ELECTRICAL SYSTEM. EPA17-24 MX Fuel Injector Connector - This bulletin has been revised to include all EPA17-24 and CARB24 PACCAR MX engines.
45-0702026-02-05. Service bulletin. ENGINE. Procedure pictures updated for clarity. When troubleshooting Cummins X15 fault codes 555 or 556, follow this additional testing, inspection, and documentation procedure to help identify the root cause of dusted engines. This is not a stand-alone process but must be used alongside Cummins troubleshooting steps. Cummins Quickserve will reference this bulletin for fault codes 555 or 556.
E3112025-09-03. Other. ENGINE; POWER TRAIN. Condition, Chassis Affected, and Warranty sections updated with the following verbiage “E311 must be flagged and open in Service Information Record (SIR) at the time of RO open date to qualify.” Also, “Through Standard Warranty or any applicable active Extended Warranty” verbiage was removed from Warranty section.
T016 / 26-0402025-06-05. Service bulletin. POWER TRAIN. T016: Warranty section updated to include 0.5 hours for test drive. Recommended Repair T016C has been updated from 6.4 hours to 6.9 hours. SRT codes updated in PRWS Claim Coding Table: B25-17A for 6.9 hours created to replace all other codes. 26-040: Warranty section updated to include 0.5 hours for test drive. Recommended Repair 26040C has been updated from 6.4 hours to 6.9 hours. SRT codes updated in PRWS Claim Coding Table: B25-17A for 6.9 hours created to replace all other codes.
32-0252024-12-03. Service bulletin. ENGINE. Info Only Unnecessary starter replacements can result from customer complaints regarding engine starting issues. A new Starter Troubleshooting Guide has been created to provide a comprehensive list of starting system checks, which should reduce unnecessary starter replacements and associated warranty claims. Engine starting system warranty claims now require a completed Starter Checklist, a Battery Pack Midtronics Report, and a Cable Drop Midtronics Report. Claims filed without these documents may be denied.
02-1942024-12-02. Service bulletin. POWER TRAIN. Fix-As-Fail The window switch fails prematurely due to excessive amperage flowing through the window switch circuit. A new door harness design has been developed to prevent failures. Fix-As-Fail start date is 11/11/2024.
7-7002024-11-05. Warranty extension. POWER TRAIN; ENGINE. 7/700 Service Agreement - Letter Only.
16-0442024-08-02. Service bulletin. SUSPENSION. Fix As Fail The height control valve (HCV) rod on vehicles with low air leaf suspensions is prone to toggling over center during rough road conditions. With full suspension articulation, HCV bracket flexes and toggles over center the HCV linkage, which results in either deflated airbags or makes them unable to inflate. Fix-as-fail start date is 07/30/2024.
E2732023-12-02. Service bulletin. ENGINE AND ENGINE COOLING. Fix As Fail Updated: Two part numbers added: 1818119 DPF Delta Pressure Sensors for MX-13-2 EMY18 2200138 DPF Delta Pressure Sensors for MX-13 -2, EMY19 Per Environment and Climate Change Canada (ECCC) regulations and guidance (Canadian Environmental Protection Act, 1999 (CEPA)), a letter has been provided to owners of Canadian registered chassis that provides a list of emissions components that have been reported (to ECCC) as having a defect.
32-0192023-03-01. Service bulletin. STRUCTURE; ELECTRICAL SYSTEM. Fix As Fail – Chassis that were manufactured with certain battery cable routing brackets may experience rubbing or chafing of the battery cables.
01-0822022-12-07. Service bulletin. VISIBILITY; VISIBILITY:DEFROSTER/DEFOGGER/HVAC SYSTEM:CONDENSOR/EVAPORATOR. Certain model 389 chassis are experiencing freezing of the A/C evaporator or frosting of the compressor and suction line. A field resolution is available to solve this issue.
34-0932022-12-05. Service bulletin. ELECTRICAL SYSTEM. 34-093 Model 389 78-inch Sleeper 12V Power Port Supplier Change
23-0052022-11-04. Service bulletin. POWER TRAIN; VEHICLE SPEED CONTROL. Clutch pedal linkage lubrication service interval information is missing from the Service manual for Model 365, 367, and 389 chassis.
45-0642022-11-02. Service bulletin. ENGINE AND ENGINE COOLING. Info Only - PACCAR is introducing Over-the-Air (OTA) software updates for engine MY17 and newer chassis equipped with Cummins X15, X12, ISX12, ISX12N, L9N, PX-7, and PX-9 engines The technology will leverage the existing Remote Diagnostic cs hardware to deliver secure software updates remotely. This will reduce downtime and save on maintenance costs for eligible vehicles.

The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.