Fix turbo control issues and “Reduced Engine Power” on your 2020–2023 Chevy Silverado or GMC Sierra 6.6L L5P Duramax with this remanufactured Synapse L5P2 turbo actuator. Pre‑programmed, direct‑fit OEM replacement with 1‑year warranty and fast shipping from NorCal Diesel Performance.
This 2020–2023 Chevrolet/GMC 6.6L Duramax L5P2 turbo actuator remanufactured by Synapse is a bolt‑on, plug‑in replacement for the factory electronic VGT actuator on updated L5P turbochargers. Supplied pre‑programmed for the 2020–2023 control strategy, it is designed to eliminate common turbo position and boost control codes, “Reduced Engine Power” warnings, and sluggish spool‑up, restoring stock‑like turbo response, towing power, and exhaust brake performance.
The L5P2 actuator is engineered for the later‑model 2020+ factory turbo and electronics package.
Intended fitment:
2020 Chevrolet Silverado 2500HD/3500HD 6.6L Duramax L5P
2021 Chevrolet Silverado 2500HD/3500HD 6.6L Duramax L5P
2022 Chevrolet Silverado 2500HD/3500HD 6.6L Duramax L5P
2023 Chevrolet Silverado 2500HD/3500HD 6.6L Duramax L5P
2020 GMC Sierra 2500HD/3500HD 6.6L Duramax L5P
2021 GMC Sierra 2500HD/3500HD 6.6L Duramax L5P
2022 GMC Sierra 2500HD/3500HD 6.6L Duramax L5P
2023 GMC Sierra 2500HD/3500HD 6.6L Duramax L5P
The L5P2 unit is a dedicated application part designed to work with the stock variable geometry turbocharger and OE engine management; it is not a universal actuator.
Uses OE‑style mounting locations, output shaft engagement, and factory electrical connector, so it installs in place of the original 2020–2023 L5P turbo actuator with no fabrication or wiring changes.
Pre‑programmed specifically for the later‑model L5P turbo geometry, vane sweep, and ECM strategy.
The L5P2 actuator: complete disassembly, inspection, and replacement of worn mechanical, electronic, and sealing components as needed.
Circuit boards are repaired or upgraded where necessary, addressing known turbo actuator weak points such as heat‑related solder failures and moisture‑related corrosion.
Final testing and calibration are performed on an actual 2020+ L5P turbocharger to confirm correct vane sweep, position feedback, and response before shipping.
Intended to resolve common late‑model L5P turbo actuator complaints such as:
Turbo position learning faults and boost control range/performance codes analogous to P003A/P0046 behavior seen on L5P trucks.
“Reduced Engine Power” messages and limp‑mode events under load or while towing.
Weak low‑end torque, slow turbo spool‑up, or inconsistent exhaust brake operation when the actuator can no longer accurately control vane position.
By restoring precise control of the variable vanes on 2020–2023 trucks, the L5P2 actuator helps return factory‑like throttle response, hill‑climb performance, and braking support on grades.
Many late‑model L5P turbo complaints originate in the actuator electronics rather than the turbo’s mechanical core; replacing only the actuator is often sufficient if the turbocharger itself is still sound.
An L5P2 actuator swap is significantly less expensive and less invasive than a complete turbocharger replacement, especially for trucks that are out of warranty or in fleet service.
The remanufactured Synapse unit aims to deliver OE‑level performance at a fraction of the cost of a new turbo assembly.
The L5P2 unit is processed through a specialized electronic remanufacturing facility with established methods for inspection, repair, calibration, and testing.
Synapse remanufactured actuators emphasize quality, root‑cause repair and robust testing over simple code clearing.
Warranty is honored through Synapse directly.
Term: 1‑year warranty from the original date of purchase.
Coverage: If the L5P2 actuator fails due to defects in materials or workmanship during the warranty period, it will be repaired or replaced at no additional charge, or the original repair cost may be refunded at the remanufacturer’s discretion.
Non‑transferable: Warranty applies to the original purchaser and original vehicle installation only; coverage does not transfer if the truck or part is sold.
Scope limits: Warranty covers only the actuator; it does not include labor, towing expenses, rentals, lost time, or any consequential or incidental damage.
Exclusions: Failures caused by incorrect installation, wiring damage, contaminated or failing turbochargers, tuning abuse, or any external system faults are not covered and may void warranty consideration.
As with the earlier L5P unit, proper post‑install calibration and diagnostic documentation are often required to evaluate a warranty claim on the L5P2 actuator.
On 2020–2023 trucks, L5P2 actuator issues present very similarly to earlier L5P actuator failures and should be distinguished from mechanical turbo problems.
Typical driver complaints include:
“Reduced Engine Power” messages, limp‑mode events, and a check engine light that may clear temporarily with a key cycle.
Noticeable power loss or lazy turbo response, particularly when towing or accelerating onto the highway.
Inconsistent or weak exhaust brake performance, especially on long downhill grades, due to improper vane control.
From a diagnostic standpoint, technicians often see:
Turbo position learning or boost‑control range/performance DTCs analogous to P003A/P0046 behavior on earlier L5P trucks, indicating the actuator cannot properly report or reach commanded vane positions.
Underboost‑type codes when the vanes fail to close adequately, even with no obvious mechanical turbo damage or excessive shaft play.
Scan‑tool data showing vane actual position that fails to track commanded position smoothly, suggesting actuator or unison ring concerns.
If mechanical inspection confirms the turbocharger itself is healthy and wiring integrity checks out, replacing the L5P2 actuator is often the recommended fix.
The installation experience for the 2020–2023 L5P2 actuator:
Physical installation:
Located on the side of the turbocharger, secured with multiple fasteners and keyed to the vane control linkage.
Access is tight but manageable with basic hand tools; many owners choose professional installation due to the confined work area and need for calibration.
Electrical connection:
Reconnects to the factory harness via an OE‑style connector; verify clean pins, secure engagement, and proper routing away from heat and chafe points.
Calibration required:
After installation, the L5P2 actuator must be calibrated on the truck using OEM‑compatible service tools so the ECM can learn the exact vane sweep and position limits.
Skipping or mis‑performing this step may result in recurring turbo position or boost control codes, even with a good actuator.
A final road test under varied load, including highway acceleration and hill climbs, should be performed to confirm proper turbo response and check that no turbo‑related DTCs return.
Yes. While both actuators serve the same purpose and share a similar reman process and warranty, the L5P2 unit is calibrated and configured specifically for the 2020–2023 L5P turbocharger and control strategy and should not be interchanged with the earlier S79‑L5P1 actuator.
If diagnostics confirm that the 2020–2023 turbo actuator and its circuit are at fault—and that the turbocharger, wiring, and boost plumbing are otherwise healthy—replacing the actuator with this remanufactured L5P2 unit is intended to resolve common turbo position and boost‑control complaints on later‑model trucks.
The L5P2 unit is pre‑programmed for its application but must be calibrated on the vehicle so the ECM can learn the vane travel range and position feedback. This is typically done with dealer‑level or equivalent diagnostic tools after installation.
This is a professionally remanufactured Synapse actuator for the 2020–2023 L5P platform, disassembled, repaired, and tested to meet or exceed OE performance. It is sold as a remanufactured part with a 1‑year warranty, not a used take‑off.
Yes, a core value applies to this part and will be charged up front at checkout. This L5P2 actuator is sold on an exchange basis that requires return of a suitable 2020–2023 L5P actuator core within 15 days for full core credit. Core condition requirements include completeness, absence of fire or flood damage, and correct application.
The actuator is an OEM‑equivalent replacement for the factory electronic turbo controller and does not alter emissions system components or calibration by itself; it is treated as a repair part for the existing turbo system. Owners remain responsible for retaining all factory emissions equipment and following applicable regulations.
