2014+ Gen V LT1 (Direct Injection) Automatic/Manual Transmission Standalone Harness

Overview

APPLICATION: ALL Gen 5 LT direct-injected engines, 5.3L, 6.2L, 6.6L, from 2014-2026.

This is a harness-only kit — the ECM is sold separately. PSI's Gen V ECM line (PCM-2001, PCM-2003, PCM-2004, PCM-2006) covers the various Gen V LT applications; contact us to source the correct ECM part number for your specific engine and model year, or see our complete KIT-LT1 Engine Controller Kit which bundles a programmed ECM (and TCM for 8/10-speed) with the harness.

DBW Only — Important for OBS Installs

Like all Gen V direct-injection LT applications, this harness is drive-by-wire (DBW) only — there is no cable-throttle option. If you select "Add Corvette Pedal (ACC-1007)" you will still need our separate 1973-1998 Chevy Truck Drive By Wire Throttle Pedal Bracket (BRK-7398, $65) to mount that pedal correctly in an OBS cab.

Parts Included

• Complete engine and transmission wiring harness
• Instruction manual

Fuel Rail Pressure Sensor Type

Not offered as a variant (too granular to select by year alone) — please specify your engine's exact model year in the order notes at checkout so we ship the correct harness connector for your Fuel Rail Pressure sensor:

• 2014-2016: 4-wire
• 2017 Corvette: 4-wire
• 2017 Camaro/Truck/CTS-V: 3-wire
• 2018+: 3-wire

Connections For

• Fuse/Relay Box
• Fuel Pump Control (relay included)
• Fan Controls
• Check Engine Light, OBD2 Port
• Accelerator Pedal
• Throttle Body
• MAF Sensor
• MAP Sensor
• Engine Coolant Temp Sensor
• Alternator Control
• (2) Upstream Oxygen Sensors
• Crankshaft Position
• Camshaft Position
• Fuel Injectors
• Coil Packs
• Automatic or Manual Transmission Control
• Knock Sensors

Transmission Compatibility

All 8 + 10 speed TCM tuning REQUIRES your TUN (Transmission Unique Number). Without the TUN#, we cannot guarantee a compatible transmission, and warranties cannot be honored without this information.

• 6L80/90E: Must be 2013+ model year transmissions to work with a Gen 5 LT system.
• 8L80/90E: 2014-2018 Gen 1 model years currently compatible. Gen 2 8-speeds (2019+) are NOT compatible.
• 10L80/90E: All 2017-2018 Gen 1 10-speed transmissions are compatible. 2019-21 2WD Truck/SUV and all 2019+ GM Performance and Camaro are compatible. 2022+ Gen 2 10-speed transmissions with electronic transmission range select (ETRS) are NOT compatible — these ETRS transmissions will only have a "park" and "out of park" position on the external shift lever on the driver side of the transmission.

Fuel System

This setup uses a fuel pump relay to send 12V power directly to a standard constant-supply fuel pump, paired with a return-style regulator (regulated to 78 psi) rather than the factory PWM fuel pump control module (FPCM). See our OBS Fuel System Swap collection (KIT-1020 / KIT-1021) for compatible return-style fuel system pairings. If a PWM fuel pump / factory FPCM setup is required for your fuel tank, PSI also offers an add-on kit (KIT-1006) to accomplish this — contact us for details.

Tuning Disclaimer

The installed tune is a base/startup tune, mirroring a factory OEM tune based on the options selected in your order. The tune will remove VATS (Vehicle Anti-Theft System), bypass VVT (if applicable), disable DOD (if applicable), and remove restrictions preventing operation of the engine when installed in a different vehicle.

Any engine or transmission modifications will REQUIRE a custom tune to ensure proper operation and prevent serious damage. PSI Conversion cannot be held responsible for issues related to operation or performance when the engine/transmission has been modified, or varies from the options selected when the tune was installed.

Notes

These harnesses are designed for retrofitting '14+ LT1/L83/L86 GEN V engines from Camaro, Corvette, Suburban, Tahoe, Yukon, Escalade, Silverado, and Sierra into older muscle cars and street rods. All harnesses require PCM VATS removal, available through PSI — contact us for more information. Harnesses are professionally constructed from Brand New GM Factory/OEM Connectors and TXL High Temperature Wire to GM Specifications, and are 100% quality inspected prior to shipping. Harness length is 4-5 feet from the rear of the cylinder head to the PCM mounting position, with a sliding grommet seal for a professional, leak-proof installation.

Real-world proof: this exact harness has already been used in a GMC OBS truck LT swap by one of our verified customers (reviewer "91 C1500"), who confirmed it as a great fit with great pricing for a GMC OBS LT swap.