Speedometer & VSS Recalibration — Mail-In Bench ECM Programming (Tire Size / Axle Ratio)
Changed tire size or re-geared your axle and now the speedometer reads off? Mail in your supported GM ECM/PCM and we rewrite the tire-size and axle-ratio calibration on the bench so speed, odometer, and shift points read true.
Supported unlocked GM ECMs/PCMs — E38 (primary), E67, E92 — verified first. Silverado / Sierra, Tahoe / Yukon / Suburban, and other GM V8 trucks and SUVs. Newer, locked, or cluster-based systems must be recalibrated at the car over OBD — verify by VIN.
How It Works
Three simple steps. Hundreds of mail-in jobs completed for shops, locksmiths, and DIY pros.
Pay & Get Address
Click "Order Now", pay securely via Stripe. We email shipping address + instructions within minutes.
Ship Your Module
Pack per the instructions and ship to Arlington. USPS goes to our PO Box; UPS and FedEx must use the street address. Customer pays shipping to us.
Receive in 1-2 Days
Work completed within 24 hours of receipt. Ships back next business day at the return speed you chose at checkout — standard to overnight. Tracking emailed.
What You Get
- Tire-size and axle-ratio parameters rewritten to match your actual setup, where supported
- Speedometer, odometer, and VSS scaling corrected so speed reads true
- Speed-based shift points corrected so the transmission stops hunting after a re-gear
- Bench read + verify of your calibration before any changes
- Calibration written back on the bench with a stable, regulated power supply
- Bench communication tested before the module ships back
- Module returned with tracking — return-shipping speed your choice at checkout
Compatibility
Confirm your part matches one of the variants below before ordering. Not sure? Text us a photo and we'll verify.
Supported controllers (verified first)
Recalibrated parameters
Common GM applications
Best for
Must be done at the car (not bench)
Will This Fix My Problem?
Honest answer: here's exactly what this service fixes — and what it doesn't.
Fixes:
- ✓Speedometer reads fast or slow after a tire-size change
- ✓Odometer drift or wrong trip mileage after larger or smaller tires
- ✓Shift points feel off or the transmission hunts after a re-gear
- ✓You changed axle ratio (gears) and speed is now inaccurate
- ✓You want the ECM to reflect your true rolling diameter and axle ratio
- ✓Cruise control and speed-based features are off after a tire or gear change
Won't fix:
- ✗Does not repair a failed or intermittent mechanical vehicle speed sensor
- ✗Does not repair cluster hardware failure (dead gauges, stepper-motor faults)
- ✗Does not recalibrate locked or unsupported controllers that require OBD/at-the-car work
- ✗Does not correct speed error caused by a wrong or worn output-shaft sensor
- ✗Does not fix ABS or wheel-speed-sensor faults
- ✗Does not roll back or alter recorded mileage — this is not an odometer service
- ✗Does not repair mechanical transmission wear or torque-converter faults
- ✗Does not repair harness, ground, or connector faults causing erratic speed signals
Legitimate recalibration only — please read before ordering
This service rewrites the tire-size and axle-ratio calibration so the speedometer and odometer reflect the vehicle's ACTUAL, current tire size and axle ratio after a legitimate tire or gear change — for repair, restoration, diagnostic, off-road, or racing use where legally permitted. It is NOT an odometer-rollback or mileage-alteration service and will never be used to misrepresent recorded mileage. Customer is responsible for ensuring this service complies with local, state, and federal law. Software programming does not repair mechanical damage — a failed speed sensor, worn output-shaft sensor, or cluster hardware fault must be repaired separately. This is not an emissions modification. A technician verifies fitment (VIN + module label) and confirms your controller is bench-readable before you ship.
Shipping Instructions
These details are also emailed to you the moment your payment clears.
Verify first: text or email us your VIN and module service / part number and we confirm your controller is bench-readable before you ship anything — many newer, locked, or cluster-based vehicles must be recalibrated at the car over OBD and cannot be done by mail. Once verified, remove the module and ship it to PO Box 120241, Arlington TX 76012 if you ship USPS — or 1168 W Pioneer Parkway, Arlington TX 76013 if you ship UPS or FedEx (UPS and FedEx cannot deliver to a PO Box). We recalibrate it on the bench, test communication, and ship it back via the return option you pick at checkout (Standard $14.95, UPS 2-Day $29.95, or UPS overnight $74.95).
What to include in your box
- Year, make, model, and engine size (e.g. 2012 Chevrolet Silverado 1500 5.3L)
- VIN of the vehicle
- ECM/PCM service number / part number off the case label
- Your NEW tire size (e.g. 33x12.50R20 or 275/65R18) and the size it replaced
- Your axle ratio (e.g. 3.42, 3.73, 4.10) if you re-geared, and the original ratio
- What is wrong now: speedo reads fast, reads slow, odometer off, or shifts hunting
- Whether any other tuning has already been applied to this ECM
- A clear photo of the module service-number label, plus your name, return address, and phone
Ship to
Auto Module Lab
If shipping USPS
PO Box 120241
Arlington, TX 76012
If shipping UPS or FedEx
1168 W Pioneer Parkway
Arlington, TX 76013
UPS and FedEx cannot deliver to a PO Box — use the street address for those carriers.
Frequently Asked
Still have a question? Text us — replies in minutes.
Can the speedometer be recalibrated on the bench by mail?
My vehicle isn't a GM — can you still do it?
What information do you need to set it correctly?
Will this fix my transmission hunting after a re-gear?
Is this an odometer rollback service?
Will it fix a broken speed sensor?
Do I need to remove the module and ship it?
How is this priced and how fast is it?
Is this an emissions modification?
Related Services
Other bench services for the same brand or use case.
GM Cluster Upgrade + Mileage Program
GM Silverado / Tahoe / Yukon / Sierra cluster upgrade or swap — including base-to-Denali — married to your VIN with mileage synced.
GM BCM Standalone Clone (2003-2015)
Clone a working GM BCM to a replacement BCM — preserves VIN, mileage, theft system, all coding.
GM Global A Virginize (Used ECM)
Reset a used GM Global A ECM/module back to a virgin, unmarried state so GM SPS / TIS2Web will program it to your VIN.
Where we serve Speedometer / Tire & Gear Recalibration
Mail-in means nationwide. See your state, metro, or specific vehicle:
Ready to ship?
Pay now, get the shipping address by email, drop it in the mail. Your module is back on your bench within a week.