Mail in the controller. Get back a calibration built for the vehicle.

Send us your (supported) GM ECM or PCM and we will modify the calibration for the vehicle, engine, and current combination. This mail-order tuning service is intended for stock, daily-driven, or mild street-performance vehicles with common modifications such as intake and cat-back exhaust upgrades, and gear or tire changes. The vehicle should be mechanically sound and running properly before tuning. If it has existing drivability problems or an active DTCs (a check-engine light) this tune will not correct those problems.

If you have an advanced build like a stage 3 cam, high stall torque converter, upgraded injectors, boost, 4L80 segment swap, or an engine swap then we recommend you get a remote tune package from us so we can support you with troubleshooting and multiple reflashes/tune updates as we get everything dialed in.

In general, this mail in service applies to all 1994 and newer GM V8 powered vehicles. The mid-1990s LT1 and Vortec Black Box applications are also supported. We also support the more performance oriented GM controllers as well, anything that was factory turbo charged or supercharged. Reach out to us to confirm if you have any doubts.

The Cadillac Northstar is not supported.

What this service includes

Custom ECM/PCM calibration for the vehicle according to your modifications (you tell us what you need in the service request form)
Fueling, ignition, throttle response, power enrichment, and torque-management changes where supported
Transmission shift adjustments when the supported transmission strategy is present (Typically Vortec Black Box and Gen 3 LS)
Support for intake, cat-back exhaust, gear, tire-size, speed governor off, DOD off, electric fan conversion, and other similar “bolt-on” style mods.
VATS and diagnostic-code setup for eligible factory or swap applications when requested

Not Included.

Injector upgrades, big cams, boost, and any combination that needs data logging, extensive drivability work, or repetitive tune updates. This is a better fit for remote or dyno tuning.

Common requests

VATS removal for an eligible factory vehicle or engine swap
DOD, AFM, or DFM disable where supported
Electric-fan enable or temperature adjustment
Speed-governor adjustment
Unused-component DTC changes for an engine swap
Differential gear-ratio and tire-size correction where the controller supports it
Base startup calibration for supported Stage 1 or Stage 2 camshaft combinations

How mail-order service works

Purchase this service.
Complete the service request form using your order number.
Remove and securely package your PCM.
We STRONGLY recommend that you use the white 9″ x 3″ x 12″ pen+gear brand boxes available at Walmart. They are strong, made in USA, and cost about $1. Most GM ECM and PCM fit in these perfectly. Just add a bit of paper on the ends to prevent it from sliding in the box during transit.
Ship it to

PCM Tuners

367 N Clarendon Ave, Unit 7

[YOUR ORDER NUMBER] – Please don’t forget this, it really helps speed up order processing.

Scottdale, GA 30079

We complete the service and return the controller with tracking.

Compatibility and exclusions

This product is not a blanket promise for every GM vehicle. Support depends on the exact year, model, engine, controller, and any HP Tuners licensing requirement.

The standard service does not include applications that require a separate controller upgrade or unlock, more than two HP Tuners credits, or another advanced access procedure. Examples that require a different or confirmed path include:

Many 2019 and newer Silverado and Sierra applications
C8 Corvette
Cadillac Blackwing platforms
Other late-model encrypted or Global B controllers
Early Northstar-powered Cadillac applications

If the vehicle falls into one of those groups—or you are unsure—submit the service request before ordering. We will confirm the correct unlock, remote-tuning, mail-in, or controller-service route.

2001–2007 Classic Sierra HD

2007.5–2014 Sierra HD

2015–2019 Sierra HD

Compatible products

Custom HP Tuners Calibration — File Only

Remote Tuning Package — MPVI4 + Custom Tune

GM Remote Tuning Package — RTD4 + Custom Tune

All GM Mail-In ECM/PCM Tuning