What Is L5P CAN BUS Plugs?
This guide covers the 2017-2023 GM/Chevy 6.6L Duramax L5P and the small terminator plugs that keep its electronics calm after a delete. We explain what L5P CAN bus plugs are, how the L5P's emissions network is wired, the 2026 legal picture, why owners fit them after a DPF delete, what a complete kit includes, how and where to install them, and the tradeoffs to weigh. Whether you search for L5P CAN bus plugs for a 2020 truck or an earlier build, the goal is the same: keep the ECM happy and the truck out of limp mode.
An L5P CAN bus plug is a small terminator that caps the factory harness connectors left behind when you remove the NOx sensors and DEF module during a delete. The L5P's CAN bus polls those modules many times per second; unplug them and the ECM sees missing nodes, logs U-codes, and can derate the engine. The plugs close the circuit with a stable, controlled-impedance loop so the network stays electrically intact.
L5P Duramax Emission System Architecture: What You're Working With
The L5P's emissions control is governed by the E41 ECM and a segmented Controller Area Network (CAN) bus. Three main aftertreatment modules talk to the ECM over the aftertreatment bus: up to three NOx sensors (depending on year), the DEF tank module (level and quality sensors), and the exhaust temperature and DPF pressure sensors. Remove a DPF, DEF, or SCR component and you also disconnect those sensors — pulling live nodes straight off the bus.
Here is the trap: on the L5P the aftertreatment and fuel-system buses are intertwined on 2020+ trucks. A missing NOx module can take down the whole segment, and because the fuel tank talks on that same segment, the ECM can lose fuel data entirely. That is why a plain "unplug and tune" on a deleted L5P often ends with a dead fuel gauge and a derate — not just a check engine light. The L5P CAN bus plugs kit exists to keep each segment terminated so the modules that remain keep communicating.
Is L5P CAN BUS Plugs Kit Legal In 2026?
The L5P CAN bus plugs kit is an emissions-defeat accessory, and like any device that defeats NOx, DEF, or DPF monitoring, it is not legal for vehicles operated on public roads under the federal Clean Air Act.
For 2026, treat the l5p CAN bus plugs kit as off-road and competition use only. The guidance here is for owners maintaining dedicated off-road or race vehicles where these modifications are permitted.
Why L5P Duramax Owners Need L5P CAN BUS Plugs For DPF Delete?
Unplugging sensors is never just a check engine light problem.
1. Limp mode and codes that won't clear
"2018 l5p. Deleted and tuned. Went into limp mode. Throwing emissions codes. Can't clear them. Unfortunately the person doing it removed hardware before tuning."— L5P owner
Skip the plugs and the ECM still sees missing nodes — ghost U-codes that no scan tool fully clears after a delete.
2. 2020+ fuel gauge dies and the ECM derates
"Unplugging NOx sensors after an L5P DPF delete turned on the check engine light."— 2020 L5P owner
On 2020+ trucks the aftertreatment and fuel buses share a segment, so a missing NOx module can blank the fuel gauge and trigger a derate.
3. One missing plug cascades into a fuel-system derate
"On my 2021 L5P I pulled the NOx sensors but skipped the plugs. It set U010F, then P0087, and the truck dropped into a low-fuel-pressure derate."— 2021 L5P owner
On 2020+ trucks the aftertreatment and fuel buses share a segment, so one unterminated NOx connector can snowball from a U-code into a fuel-pressure fault and a real derate. The plug closes that node so the cascade never starts.
What A Complete L5P CAN BUS Plugs Kit Should Include
A proper L5P CAN BUS plugs kit terminates every connector the delete leaves open, year-correct for your truck. Below are the kits we sell, each with the exact parts, fitment, and a buyer note. Use code DPF12 for 12% off.
CAN BUS Plug Kit For 2020-2023 L5P 6.6 Duramax Chevy GMC
- Fits 2020-2023 L5P (E41); terminates NOx and DEF harness connectors so the ECM sees valid nodes.
- Silicone-sealed ABS housings resist heat, moisture, and under-hood vibration for long-term integrity.
"Works as it should." — Tim M.
View & Buy with Code: DPF12 to Get 12% OffBlack CAN BUS Plug Kit For 2017-2019 L5P 6.6 Duramax Chevy GMC
- Year-correct for 2017-2019 L5P (E41); covers the three NOx connectors these trucks use.
- Keyed, color-coded plugs seat one way and click locked.
"Fast shipping. Works good." — Jeff L.
View & Buy with Code: DPF12 to Get 12% OffWhite CAN BUS Plug Kit For 2017-2023 L5P 6.6 Duramax Chevy GMC
- Same proven terminator circuit as the black kit, in a white housing for easy ID at the harness.
- Maintains full CAN bus continuity so the ECM never logs a lost-communication fault.
Need the DPF delete pipe, EGR delete kit, and downpipe exhaust together with your CAN bus plugs? Check 2017-2025 L5P 6.6L Duramax Applicable Product.
2017-2025 L5P 6.6L Duramax Applicable Product
- Includes the 4" DPF race pipe, 3.5" downpipe exhaust, and EGR delete kit, and of course, with CAN bus plug kit.
"This kit is worth every single penny. My Duramax feels like an entirely different truck now. The throttle lag is completely gone, and the power delivery is incredibly smooth. The components are heavy-duty and the fitment was spot on. Highly recommend!" —
View & Buy with Code: DPF15 to Get 15% OffInstallation Overview For L5P CAN BUS Plugs
The CAN bus plugs are the final step of an L5P delete, fitted after the NOx sensors and DEF module are physically removed. Always disconnect the negative battery terminal first to avoid CAN network errors, then work through the connector locations shown in the included L5P CAN test-plug installation diagram.
Install plugs in the following locations:
Risks, Tradeoffs, And Responsible Use Of L5P CAN BUS Plugs
What You Gain
L5P CAN bus plugs are cheap insurance against ghost codes and limp mode after a delete. They keep the ECM from derating, support a clean tune, and make the truck drivable the moment the emissions hardware comes off. For a 2017-2019 truck you need three NOx plugs; for 2020+ you need two NOx plugs plus the larger DEF connector.
What to Watch
The plugs are a defeat device — off-road and competition use only, never on a street-registered truck. They do not disable diagnostics by themselves; a proper off-road tune is still required or codes remain. Note that 2024-2025 L5P (E42) trucks generally do not use these plugs. Seat every connector fully, confirm the fuel gauge on 2020+ builds, and verify your local emissions laws before modifying.
Not sure which CAN bus plugs kit fits your L5P, or want help pairing it with a delete tune? Email us at service@dpfexhaust.com — we'll help you choose the right path for your Duramax.
We hope this guide helps you out.
Have a great day! 🙂
