The "Locked PCM" Problem: How to Actually Tune Your 2019+ RAM 1500
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You just installed a massive leveling kit and heavy 35-inch mud terrains on your 2019–2024 RAM 1500.
Now, your speedometer is off, the transmission shift points feel incredibly sluggish, and you desperately need a little more power to turn that extra rubber. You go online to buy a standard handheld tuner, just like you did for your old early-2000s truck.
Stop. You are about to run face-first into the Locked PCM wall.
Starting heavily in 2015 (and locked down even tighter on the 5th Gen models in 2018+), RAM heavily encrypted the Powertrain Control Module and installed a physical Security Gateway Module (SGW) behind the dashboard. If you try to plug a standard, generic tuner into your OBDII port, it will immediately flash "Error" or "Locked."
To tune these modern trucks, you have to bypass the security wall.
Fortunately, industry leaders like SCT Performance and Bully Dog have engineered exact solutions. Using specific Security Bypass Cables—and in some cases, an Unlocked PCM Swap—you can safely communicate with your truck's brain.
In this guide, we explain exactly how these encrypted modules work, what hardware you need to bypass them, and how you can finally fix your speedometer, add serious horsepower, and permanently disable MDS on your 5.7L Hemi.
Compare Performance Upgrades
More Airflow or Custom Calibration?
|
Upgrade Type |
Top Brands |
Installation |
Best For |
|
Handheld Tuner |
SCT Performance |
Medium. (Requires Bypass Cable/Unlock). |
Maximum Power. Adds proven horsepower, completely disables the annoying MDS 4-cylinder mode, and fixes the "dead pedal." |
|
Performance Monitor |
Bully Dog (GT) |
Medium. (OBDII + Bypass). |
Towing. Mounts on the dash to tune the truck while actively monitoring critical transmission and coolant temperatures. |
|
Cold Air Intake |
aFe (Momentum GT) |
Easy. (Bolt-on). |
Sound & Efficiency. Replaces the restrictive factory airbox to provide a massive induction roar and sharper throttle snap. |
|
High-Flow Filters |
K&N Engineering |
Instant. (Drop-in). |
Budget Performance. A washable, reusable cotton-gauze filter that slightly improves airflow without replacing the whole intake tube. |
Frequently Asked Questions (Performance)
How do I disable the MDS (4-Cylinder Mode) on my 5.7L Hemi?
You need a premium tuner.
The 5.7L Hemi artificially shuts down 4 cylinders on the highway to save a fraction of gas, which often causes a terrible, helicopter-like droning sound (especially if you have an aftermarket exhaust). A handheld tuner from SCT Performance or Bully Dog allows you to completely turn off the MDS system within the truck's computer, keeping you in smooth V8 power 100% of the time.
Will installing a Cold Air Intake void my RAM's factory warranty?
No, you are protected by federal law.
In the US, the Magnuson-Moss Warranty Act protects consumers. A dealership cannot automatically void your entire bumper-to-bumper warranty simply because you installed an aFe or K&N intake, unless they can explicitly prove the aftermarket part caused the specific failure (e.g., you installed the filter incorrectly and sucked dirt directly into the engine).
How do I fix the "Dead Pedal" throttle lag?
By recalibrating the drive-by-wire maps.
The 2019+ RAM uses an electronic "drive-by-wire" gas pedal that is intentionally programmed from the factory to open the throttle body slowly, making the truck feel sluggish off the line. Flashing the truck with an SCT Performance tune physically rewrites this map, drastically sharpening the throttle response so the truck reacts instantly the second you touch the pedal.
Unlock the beast.
Fix the terrible throttle lag and add the horsepower RAM left on the assembly room table. Shop our verified collection of premium 2019–2026 RAM 1500 Engine & Power Upgrades.