HP Tuners CORE ECU Installation Guide
Last reviewed: November 9, 2026
This guide walks you through installing the HP Tuners CORE ECU on a GM LS engine, from pulling the old computer to the first start. It is written by The Tuner Store, an authorized HP Tuners reseller, from HP Tuners' published installation information. Always follow the documentation that comes with your ECU and harness. If anything here differs from it, the HP Tuners documentation wins.
Before you start
- Who it's for: the CORE ECU is intended for exempt vehicles, such as pre-emissions vehicles and documented competition vehicles used only on the track.
- Register first: you must register the ECU and identify the vehicle application before installation and use. Skipping this voids the warranty.
- Warranty: HP Tuners covers the ECU for 2 years, starting when the unlock code is entered, and harnesses for 3 months.
- Engines covered: Gen III LS (drive-by-cable) and Gen IV LS (drive-by-wire).
What you'll need
- CORE ECU and a CORE harness (Gen III DBC, Gen IV DBW or the 15' flying lead)
- Two Bosch LSU 4.9 wideband oxygen sensors (Bosch part number 17025)
- A Windows laptop with VCM Live installed (free download from HP Tuners)
- An Ethernet cable and a USB-to-Ethernet adapter
- An internet connection for activation
- Basic hand tools and zip ties
- Optional, for custom wiring: crimper, wire loom, heat shrink, heat gun and wire cutters
Laptop requirements for VCM Live
- Windows 10
- Quad-core Intel Core i3 class processor or better
- 8 GB of RAM
Safety
- Disconnect the battery before you touch the wiring, and reconnect it last.
- Double-check battery polarity. Reversed polarity can damage the ECU.
- Unplug the ECU before doing any welding on the vehicle.
- Make sure no wire has damaged insulation and nothing can short to ground.
- Check for fuel leaks before the first start.
- Keep the ECU and harness away from exhaust and other heat sources.
Step 1: Remove the old ECU
- Disconnect the battery. Remove it if it is in the way.
- Unplug and remove the factory ECU.
- Remove the old engine harness and brackets if you are replacing them.
Step 2: Mount the CORE ECU
- Pick a clean, flat spot away from moving parts, heat and heavy vibration. The original ECU location is usually the best choice.
- Mark and drill four 5 mm mounting holes.
- Fasten the ECU with the four supplied lock washers and nuts.
- Tighten to 1.4 N-m (about 12 in-lb). Do not overtighten.
Step 3: Route and connect the harness
- Pass the harness through the firewall.
- Keep the harness at least 6 inches from major heat sources. Where you can't, add heat shielding.
- Connect every sensor and actuator connector on the engine.
- Plug in ECU connectors A, B, C and D. Connector A has 34 pins, B has 26, C has 34 and D has 26.
- Bolt the black ring-terminal ground wires to the chassis, engine block or cylinder head. Both can share one ground point.
- Reconnect the battery last.
Cam sensor note: the Gen III DBC harness places the cam sensor connector at the rear of the engine. Some early LS2 engines with a 24x crank wheel have the cam sensor at the front and need an extension.
Connector life: the ECU connectors are rated for 25 plug and unplug cycles. Don't unplug them more than you need to.
Step 4: Connect VCM Live for the first time
- Install VCM Live on your laptop.
- Go to Tune, then Open Tune, and choose a base tune from the VCM Live Tunes folder.
- Connect the laptop to the female Ethernet pigtail on the harness using the USB-to-Ethernet adapter.
- Turn the key on with the engine off, then click Connect.
- Complete the Activation Acknowledgment.
- Enter your unlock code. The ECU warranty period starts here.
- Create or open a layout.
Step 5: Run the Pre-Start Setup Wizard
- With the key on and engine off, check for trouble codes and fix them first.
- Fix any mechanical problems before going further.
- Go to Tune, then Setup Wizard.
- Select the part number for each sensor on your engine.
- Confirm every parameter shows a believable, working value.
- Confirm the fuel pump primes.
- Click OK. The settings are sent live, or with your next write.
Good to know: the wizard does not remember your selections between sessions. Save your tune once it is set up.
Wiring reference
Main power pins
Each of these pins is limited to 10 amps.
| Pin | Function |
|---|---|
| D7 | ECU main power |
| C1 | Ignition switch |
| A1 | Throttle body power |
Ignition outputs
Outputs follow the LS firing order: 1-8-7-2-6-5-4-3.
| Output | Cylinder | Pin |
|---|---|---|
| 1 | 1 | A19 |
| 2 | 8 | A12 |
| 3 | 7 | A20 |
| 4 | 2 | A13 |
| 5 | 6 | A21 |
| 6 | 5 | A14 |
| 7 | 4 | A22 |
| 8 | 3 | A15 |
Injector outputs
| Output | Cylinder | Pin |
|---|---|---|
| 1 | 1 | A3 |
| 2 | 8 | A4 |
| 3 | 7 | A5 |
| 4 | 2 | A6 |
| 5 | 6 | A7 |
| 6 | 5 | A32 |
| 7 | 4 | A31 |
| 8 | 3 | A30 |
The firing order can be changed in VCM Live under Cylinder Firing Order, but the wiring must still follow the tables above.
Dual injection: the ECU runs 8 primary and 8 secondary injectors in fixed pairs on the same cylinder (outputs 1 and 9, 2 and 10, and so on through 8 and 16). The pairs cannot be reassigned.
Sensor part numbers
Part numbers are as listed by HP Tuners. Confirm against your engine before you order.
| Sensor | Gen III LS | Gen IV LS |
|---|---|---|
| Crankshaft position | GM 12560228 / ACDelco 213-354 | GM 12585546 |
| Camshaft position | GM 12561211 / ACDelco 213-363 | ACDelco 213-3826 |
| Throttle position (TPS) | GM 17123852 / ACDelco 213-912 | Not used (drive-by-wire) |
| Accelerator pedal position | Not used (cable throttle) | Varies by vehicle |
| Manifold pressure (MAP) | GM 19418810 or 12614970 | GM 12591290 or 12644228 / ACDelco 213-4434 |
| Coolant temperature | GM 15326388 / ACDelco 213-953 | GM 15326388 / ACDelco 213-953 |
| Intake air temperature | GM 12160244 / ACDelco 213-243 (not used with the 5-wire MAF) | GM 12160244 / ACDelco 213-243 |
| Oil pressure | GM 12677836 | GM 12673134 |
| Wideband oxygen (two required) | Bosch LSU 4.9, 17025 | Bosch LSU 4.9, 17025 |
| Knock | ACDelco 213-3521 | ACDelco 213-1576 |
| Mass air flow (MAF) | 3-wire: GM 25179711 / ACDelco 213-364 (separate IAT sensor required). 5-wire: GM 25168491 / ACDelco 213-4657 (LS1, LS2, LS6) | GM 15865791 / ACDelco 213-4222 |
| Barometric pressure | 30-2130-15 | 30-2130-15 |
| Throttle body | TPS GM 17123852, idle air control GM 17113598 | GM 12570790 |
| Idle air control | GM 17113391 / ACDelco 217-1806 | Not used (drive-by-wire) |
| CAN connector | DT AT04-4P, wedge TPA-AW4P, terminal AT60-202-16141 | DT AT04-4P, wedge TPA-AW4P, terminal AT60-202-16141 |
Harness options
- Gen III DBC harness: early LS engines with a cable throttle.
- Gen IV DBW harness: later LS engines with drive-by-wire.
- 15' flying lead harness: for a fully custom build. Comes with connector diagrams and is meant for experienced wirers.
- Transmission sub-harness: plug-and-play control of GM 4L60E and 4L80E transmissions.
- I/O sub-harness: a 5-foot flying lead for extra inputs and outputs such as added sensors, fans and pumps.
All of these are available on our CORE ECU product page.
Troubleshooting: laptop won't connect
- Make sure the key is on and the Ethernet cable is fully seated at both ends. The optional harness includes a 2-meter Ethernet branch that reaches into the cabin.
- In Windows, open View network connections and check the adapter's IPv4 settings.
- Reset the adapter: open Device Manager, right-click the USB-to-Ethernet adapter and choose Uninstall device. Leave the "delete driver" box unchecked, then restart the laptop.
About this guide
We review this page regularly against HP Tuners' current CORE ECU documentation. The date at the top shows the last review. Full connector pinouts, the mounting dimension drawing and electrical schematics are in the documentation supplied with your ECU and harness.