This Synapse Transmission Control Module (TCM) with PPEI custom tuning is a fully remanufactured Allison controller for 2011–2015 GM 6.6L LML Duramax trucks, combining a fresh A50/T14 module with professionally calibrated PPEI transmission tuning for improved performance, drivability, and reliability under load. It arrives VIN‑programmed and tune‑loaded for plug‑and‑play installation, using the same physical hardware as the stock replacement but with enhanced shift strategy tailored to your truck’s use and power level.
IF YOU HAVE A CUSTOM TUNE INSTALLED IN YOUR TCM ALREADY, PLEASE CALL US PRIOR TO ORDERING TO ENSURE WE CAN TRANSFER YOUR TUNE
The Synapse S72‑1G01115GD‑PPEI “2011‑2015 Duramax – Allison TCM Exchange with PPEI Tuning” is a direct‑fit remanufactured Allison transmission control module pre‑loaded with PPEI custom transmission tuning for 2011–2015 Chevrolet and GMC 6.6L LML Duramax trucks. This exchange TCM replaces the factory A50/T14 module, correcting common electronics failures while upgrading shift points, torque‑converter strategy, and overall shift feel to better match tuned engines, towing, and larger tires.
Application: 2011–2015 Chevrolet and GMC 6.6L LML Duramax with Allison automatic transmission.
Typical trucks covered:
2011–2015 GMC Sierra 2500HD / 3500HD 6.6L Duramax.
2011–2015 Chevrolet Silverado 2500HD / 3500HD 6.6L Duramax.
TCM family: A50 / T14‑style Allison TCM used on 2009–2015 Duramax applications (this listing is specifically calibrated for 2011–2015 LML).
Service type: Exchange remanufactured TCM including PPEI custom transmission tune; your original TCM core is returned after installation.
Emissions note: Transmission‑only tuning does not alter engine fuel or timing maps, but local laws vary; customers are responsible for ensuring compliance with regional regulations.
Brand: Synapse
SKU / Item #: S72‑1G01115GD‑PPEI
Condition: New, fully remanufactured module with new programming
OEM cross‑reference examples: A5100S92, A5100NC6, 19431596, 24256861, 24259874, 24257038, 24266710 (representative A50/T14 part numbers)
UPC: 645716739792
Weight / dimensions: Approx. 3 lb; packaging roughly 5 x 10 x 10 in
Electrical: Designed for OEM 12‑volt GM light‑duty truck systems within factory voltage range
Enhanced shift points to better match powerband, turbo response, and load, helping the truck shift at more optimal RPMs under acceleration and while towing.
Reduced unnecessary torque‑converter slip to get more power to the ground and reduce heat, improving throttle response and acceleration while helping protect the torque converter.
Refined shift timing and firmness to reduce flare, hunting, or “lazy” factory shifts, delivering a more confident, performance‑oriented yet daily‑drivable feel.
Each module is fully remanufactured, then programmed for your truck’s specific VIN and configured with PPEI’s custom transmission calibration prior to shipping.
Plug‑and‑play install: In normal situations no additional dealer‑level flashing is required; once installed, the TCM communicates with the ECM and other modules like a factory unit.
Addresses typical A50/T14 electronics issues such as internal board failures, communication dropouts, and corrupted logic that cause limp‑mode, harsh shifts, or inoperative manual mode.
Helps prevent further transmission damage by restoring reliable control of line pressure, shift scheduling, and converter lockup on trucks already running higher power engine tuning.
The core module is torn down, inspected, and rebuilt, with known‑failure components on the board replaced or upgraded to more robust equivalents wherever possible.
Each TCM is bench‑tested to verify CAN communication, input processing, and solenoid driver outputs before programming and shipment.
This item is a exchange TCM for 2011-2015 Chevy and GMC Pickups with LML/LMM Duramax diesel, adapted to include PPEI calibration.
Order & vehicle info
Add the “2011‑2015 Duramax – Allison TCM Exchange with PPEI Tuning” to your cart and complete checkout on norcaldieselperformance.com.
Provide accurate vehicle details and your VIN so the TCM and tune can be built specifically for your truck.
Programming & PPEI tune loading
Your remanufactured TCM is programmed to your VIN and loaded with the appropriate PPEI custom transmission tune.
The unit is then sealed, final‑tested, and prepped to ship as a ready‑to‑install module.
Shipping
The exchange TCM typically ships via ground service, with expedited options often available at checkout for time‑sensitive repairs.
You receive installation and core‑return instructions via your NorCal order confirmation and package insert.
Installation on your truck
Disconnect both batteries, remove the original A50/T14 TCM, install the Synapse/PPEI module, reconnect batteries, and verify operation with a road test.
Core return
Once your truck is up and running, package your original TCM with several inches of padding on all sides and ship it back according to the instructions from NorCal Diesel Performance.
Your original TCM must generally meet the following conditions to qualify as a valid core:
No fire damage.
No severe flood or corrosion damage.
Must be an A50 or T14 Allison TCM; housing and connectors must match.
Circuit board and case intact with all components present (previous repair attempts are acceptable if not burned beyond repair).
The hardware side of this TCM is functionally identical to the non‑tuned exchange unit; it targets the same failure patterns while adding improved shift strategy through PPEI tuning.
Limp‑mode with limited gear range (often stuck in 3rd or 5th) even though the transmission is mechanically sound.
Erratic, harsh, or delayed shifts; flare between gears; or refusal to downshift under load or while towing.
Loss of manual/tap‑shift function in M range while PRNDL still displays normally.
“Service Transmission” or similar messages coinciding with gear‑selection or shift problems.
Intermittent no‑crank or no‑start conditions due to TCM‑ECM communication failures on the CAN bus.
While codes will vary by truck and failure mode, many TCM issues on LMM and LML Duramax trucks involve:
U0101 – Lost Communication with TCM.
P0700 – Transmission Control System Malfunction (ECM flag).
P0711 / P0713 – Transmission Fluid Temperature Sensor Performance / High Input.
P0729–P0736 – Gear ratio error codes when shift control or feedback fails.
This exchange unit cannot repair internal clutch damage, failed torque converters, or wiring/fuse/ground issues; proper diagnosis is recommended before assuming the TCM is at fault.
Term: 2‑year, no hassle warranty on the remanufactured TCM starting from the purchase date
Coverage:
Failures due to defects in materials or workmanship on the remanufactured electronics and loaded tuning file.
If a covered failure occurs within the term, the manufacturer may repair the module, replace it, or refund the repair cost at its discretion.
No coverage for damage caused by improper installation, shorted harnesses, incorrect wiring repairs, or failed external components.
No coverage for damage from fire, severe water intrusion, collision, or other physical abuse.
Labor, towing, rental cars, downtime, and other consequential damages are excluded.
Warranty applies only to the original purchaser and is not transferable.
Always review NorCal Diesel Performance’s online policies and your specific order confirmation for the warranty on this tuned TCM.
This PPEI version uses the same hardware and reman process as the stock Synapse exchange TCM but adds PPEI custom transmission tuning on top of the VIN‑matched programming. The non‑PPEI unit retains factory shift logic, while this SKU optimizes shift timing, converter behavior, and line pressure for improved performance, towing, and response.
No, the module will operate on an otherwise stock truck and improve shift strategy and converter control on its own. However, it is especially beneficial on trucks that already have engine tuning or bolt‑on modifications, since the transmission logic is better aligned with the added torque.
Yes. The exchange TCM is VIN‑programmed and tune‑loaded before shipment, so you install it, reconnect the batteries, and perform a test drive; no dealer‑level reflash is typically required. Trucks with unusual custom setups or prior non‑PPEI tunes may need additional coordination with your tuner.
If you are switching from another tuner, this exchange TCM will overwrite that logic with PPEI’s calibration while retaining VIN‑correct data. In most cases, you do not need your old tuning files, but any engine tunes should be compatible with the increased line pressures and altered shift strategy PPEI provides.
Reference programs require receipt of your original TCM core within roughly 30 calendar days of the exchange unit’s ship date. Sending your core back promptly ensures full core credit and keeps turnaround times low for other customers.
Moderate electronic failures and even many attempted repairs are may be acceptable, but TCMs with fire damage, heavy corrosion, or missing board sections may be rejected as non‑rebuildable cores. If your original module is badly burned or waterlogged, contact NorCal Diesel Performance prior to ordering to discuss core eligibility and any extra charges.
For LML Duramax owners who want both a reliable fix for a failing A50/T14 controller and a meaningful improvement in how their Allison behaves under power and load, this Synapse 2011–2015 Duramax Allison TCM Exchange with PPEI Tuning delivers a tuned, VIN‑matched, ready‑to‑install solution backed by a proven reman program.
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