L5p Egr Delete Instructions

What the L5P EGR Delete Actually Involves

The L5P is a 6.6L Duramax diesel that General Motors and Duramax Diesel put under the hood of the 2017-through-2022 heavy-duty trucks, and the EGR system on these engines is a serious design. It runs cooler exhaust gas back into the intake to knock down combustion temperatures, which keeps NOx emissions in check for the EPA but also means carbon builds up inside the intake manifold, EGR cooler, and valve over time. A delete removes that loop entirely, usually with a tune and some hardware swap, and it is one of the most common mods people do on these trucks. Here is the straightforward version of what you are actually doing. You start with a tune that disables the EGR function in the PCM. Then you physically block or remove the EGR passage so air can flow cleanly through the intake without that recycled gas. Most people go with an EGR delete plate or a clogged-off pipe rather than a full tube replacement because the factory hardware is bolted together in a tight space and the plates do the job without requiring every sensor to be unplugged. You need a tuner that supports L5P EGR disable functions. The popular options are the HP Tuners VCM Editor custom tune, the S&B EGR delete kit with its associated software support, the DIABLX INK-1000 tuner, or the FICM Power/Eliot custom tunes from various vendors. Whatever tool you use, it has to be capable of turning off the EGR duty cycle, disabling the EGR temperature and position sensor monitoring, and deleting the related DTC codes. If your tuner does not have EGR delete capability built in or cannot handle the code deletion, you will get lights on the dash no matter what hardware you install.

What You Need Before You Start

Basic hand tools, a ratchet set, Torx bits for the EGR valve bolts, a socket set for the intake piping, and a jack with stands if you are going underneath to access the lower EGR piping. A scan tool that can read and clear codes on a GM truck is useful but not strictly necessary if your tuner handles the software side. Some people prefer to pull the negative battery terminal before touching anything near the EGR valve, and that is a reasonable precaution because you are working near sensors that could short out if a wrench bridges two pins. Expect to spend between forty-five minutes and two hours on the hardware portion if you have never done it. The first time I did this on a 2019 Silverado 2500 HD, it took me about an hour and a half because the lower EGR pipe on the L5P is routed behind the oil cooler line and requires you to unclip a couple of brackets just to get the pipe loose. I had to wiggle the pipe at an angle and use a flex-head ratchet for one of the lower bolts. If you have a lift and good lighting, it goes faster. On a jack stand with a flashlight in your teeth, it takes longer.

Step-by-Step Hardware Procedure

Start by removing the air intake assembly if your delete kit calls for it. Some kits require you to take off the entire mass air flow sensor housing so you can bolt the delete plate into place where the EGR tube meets the intake manifold. Other kits are designed to stay inline with the existing piping, which means you leave the MAF intact and just block the EGR flow path. Disconnect the electrical connector from the EGR valve. There is a single plug on top of the valve. Push the tab and pull straight out. Do not twist the connector because the pins can bend if you torque them sideways. Remove the two or three bolts holding the EGR valve to the intake manifold. On the L5P, these are typically M8 or M10 bolts, sometimes with a Torx head. Keep track of which bolt goes where because the threads can have different lengths depending on the mounting location.

Once the valve is loose, you can either pull it away and slide in a metal delete plate that covers the EGR passage, or you can remove the valve entirely and replace it with a blanking plate. The plate should seal properly against the gasket surface. If the old gasket is torn or stuck to the manifold, scrape it off gently. Do not dig into the aluminum surface with a metal tool because you will score the gasket mating face and then you will have an exhaust leak at the EGR port. For the piping side, there are two common approaches. Some mechanics leave the upper EGR tube in place and just block off the valve side. Others remove the entire EGR cooler and tube assembly and replace it with a straight pipe or a delete tube. The delete tube approach is cleaner for airflow because it eliminates the dead volume of the cooler, but it requires more disassembly. You will need to disconnect the coolant lines from the EGR cooler if you go that route, and that means you will lose some coolant and need to refill and burp the system afterward. reinstall any intake components you removed in step one. Torque everything to spec. The EGR valve bolts on the L5P are typically around 20 foot-pounds, but check your specific kit instructions because some aftermarket plates use different hardware.

The Tuner Side

This is where people mess up. Installing the hardware is the easy part. Getting the PCM to stop trying to control the EGR is where the headache happens. You need to load a tune that disables EGR duty cycle, deletes the P2002, P2008, P2016, and any other EGR-related codes, and ideally adjusts the fuel maps and timing to compensate for the hotter combustion environment that results when you remove the EGR loop. If you skip the tuning step and just install the hardware, the truck will throw codes immediately, run in limp mode, and the PCM will still be trying to actuate a valve that is now sealed shut. You will get a check engine light and possibly a reduced power message within minutes of starting the engine. Do not skip the tune. When you load the new tune, make sure the truck battery is in good condition. A weak battery during a flash can brick the PCM. I learned this the hard way on a project truck at a friend's shop when the battery voltage dropped below ten volts mid-flash and the tuner threw an error. We had to pull the PCM and reflash it with a bench tool, which added two hours and about a hundred dollars to the job. Charge the battery or hook up a maintainer before you start the tune.

Real World Results

After the delete is installed and the tune is loaded, the truck will run noticeably differently. The intake stays cleaner because there is no recirculated exhaust gas coating everything in soot. Oil life may improve slightly because the EGR gas does not blow past the rings and contaminate the crankcase as quickly. Fuel economy often goes up by one to two miles per gallon in real-world driving, though you will not see the massive gains that some forums claim. The engine runs a bit hotter in the combustion chamber since you removed the dilution effect of the EGR gas, which is why proper tuning is critical. A well-tuned delete can actually run more conservative timing and boost targets than stock in some drive modes to keep cylinder head temperatures reasonable. There is a problem that comes up specifically with the L5P delete that is not well documented. The MAF sensor on the L5P can throw a code if the tune does not adjust the MAF calibration table to match the new airflow characteristics. After the EGR is deleted, the air flows a little differently through the intake because the cooler and tube are gone, and the MAF readings can drift slightly. I encountered this on a 2020 Sierra after a customer installed a delete kit and had a persistent P0101 code that would come and go. The fix was not another hardware change. It was adjusting the MAF airflow calibration curve in the tune file. I had to pull the live data, compare the MAF grams per second at idle and wide-open throttle against the stock values, and then tweak the calibration table until the error band fell within acceptable range. Without that step, the check engine light would reset every time you cleared it.

Important Limitations and Warnings

Smog inspection is the big one. In states that require smog checks, a deleted EGR system will fail every time. California, New York, and several other states have emissions testing that will detect the missing component or the altered tune. Even in states without smog checks, the federal Clean Air Act makes it illegal to remove emissions equipment on a road-going vehicle, and the EPA has been increasingly aggressive with fines. This is not theoretical. There have been documented cases of shops and individuals getting fines in the tens of thousands of dollars for selling or installing EGR delete kits. There is also the warranty consideration. If your truck is still under powertrain warranty, a deleted EGR system gives the dealer a clear reason to deny coverage on engine-related repairs. They can and will trace engine failures back to the delete if they feel like it. Even if the failure is unrelated, the paperwork trail can be problematic. Sales tax and registration may also be affected in some jurisdictions. A few states require you to disclose modifications at renewal, and a tampered emissions system can flag the vehicle for inspection.

A Few Things People Miss

The first thing is that a delete does not automatically solve every EGR-related problem. If your truck is already burning oil or has a cracked EGR cooler, deleting the system does not fix the underlying engine wear that caused those issues in the first place. You might get better mileage, but the truck will still have whatever mechanical problems it already had. The second thing is that not all tuners treat the L5P the same. Some custom tunes assume you are running a complete intake delete including the EGR cooler removal, while others are designed for an EGR valve plugging only. Running the wrong tune for your hardware setup can cause rough idling, excessive black smoke, or in extreme cases, detonation from overly advanced timing with no EGR dilution. Always confirm the tune matches your exact hardware configuration before you flash it. Finally, the L5P has a more complex EGR system than the earlier LMM and LML engines. The cooler is positioned differently, the piping is tighter, and the PCM strategies are more aggressive about monitoring EGR flow. This means the delete process is not a simple bolt-on in every case. Some vehicles require a custom fabrication piece to route the intake piping around the oil cooler line, and that extra work is why the install time varies so much from truck to truck.