Installation Instructions for Chevy/GMC Duramax LM2/LZO 3.0L Stealth Module (2019-2024)

Included With Purchase

(1x) Stealth Module
(1x) Wire Harness with Fuel Rail Sensor and MAP Connections
(1x) Selector Switch


Video Installation


Step by Step Instructions

Let your truck sit with the hood popped, doors shut and the key fob away from the vehicle for at least 20 minutes. It is important to keep the key fob away and the doors shut during the entire installation process. DO NOT bring the key fob near the vehicle or open any doors until AFTER the module is fully installed and connections are verified. This allows the computer to 'sleep' and for your engine compartment to cool down. Failure to do so will result in a check engine light on startup.

 Step 1:

First step is to remove the engine cover for better access. Remove one 10mm bolt and the oil cap to lift cover off. REPLACE OIL CAP so nothing drops in the open oil fill hole.

Sensor Connections

Sensor Connections

 Step 2:

The fuel pressure sensor is located directly under the intake plenum towards the front of the engine. Slide the white locking tab away from the sensor. Pinch the tab on the connector and pull the connectors apart.

Sensor Connections

Step 3:

Plug one end of the Stealth Harness into the connection you just removed and the corresponding pigtail into the sensor connection.

 Step 4:

Remove the rubber intake hose from the air filter housing. You can also remove the top of the air filter housing and even the coolant reservoir for better access if necessary.

Sensor Connections

Sensor Connections

Step 5:

Unlock the map sensor connector by pulling the white (LM2) or red (LZO) locking tab away from the sensor. Squeeze the tab on the connector as you pull the connector away from the sensor. Plug the Stealth harness into the sensor and the corresponding pigtail into the connector you removed.

 Step 6:

Route the wires towards the air filter housing and plug in the grey main connector into the Stealth Module. Ensure that the grey main connector is securely fastened with both clips engaged into the Module. There is space next to the air filter housing that the Module can be tucked in securely. Plug in the selector switch.


Turn Dial Clockwise

Stock - Low - Medium - High

Low - Towing at or near the vehicles maximum legal tow rating and low traction situations.
*consult your owners manual for vehicle tow rates

Medium - Moderate towing, around the middle of your vehicles tow rating, and ideal for everyday driving situations.

High - Maximum performance. Ideal for empty highway cruising.

The switch must remain plugged into the Stealth Module to remain in the desired setting. Do not switch power levels with the engine running.

You will see the best results when the selector switch is left in one setting for as long as possible.

Check Engine Light or Hard start on Install?

The most common reason for a check engine light on install is due to the truck not being asleep. If the Stealth Module has already been removed, please start the installation process over while giving special attention to the instructions above step 1. If the Stealth Module is still installed, verify connections and disconnect the negative terminals on your battery for a hard reset. Events that will wake the truck up: Not letting it sit for 15 minutes, opening/closing the vehicle door, having the key near the truck during install.

The most common reason for a hard start on install is due to improver connection. Please verify that all connections are straight and pushed in all the way. Be sure the harness is pushed in tight to the Stealth Module as well.

If you are still having trouble, please give our 24/7 tech support a call at (888) 613-4304

Remove the Stealth Module Before Service

Before going in for service, please remove the Stealth Module so that the truck is back to stock. This allows the technician to have a fresh base line when performing any work.