Find Your Vehicle’s “Test Group” / “Engine Family” Number (VECI Label) for J1667 Smoke Opacity Testing
Scheduling a mobile Motorhome or Diesel Smoke Opacity (SAE J1667) test? Find the Engine family name if possible.
We need your Test Group or Engine Family number before we drive to you. If this identifier isn’t visible at the appointment, the test can’t be completed and may be recorded as a failure by default. Sharing it in advance keeps your visit fast and successful.
Questions or ready to book?
📞 916-890-4427 | ✉️ support@norcalcarbmobile.com
Why this number matters for J1667 opacity testing
Every U.S. vehicle has a drivetrain identifier called the Test Group or Engine Family number. It tells us the precise emissions configuration your vehicle was built to meet and ensures we bring the right gear and follow the correct procedure for your California diesel smoke opacity (SAE J1667) inspection—especially important for motorhomes (RVs), heavy-duty pickups, and commercial diesels.
Where to find the label (VECI)
Look for the Vehicle Emission Control Information (VECI) label in the engine area. Common locations:
Underside of the hood (most common)
Radiator support/core support
Engine cover or air intake shroud (rear-engine motorhomes often place it there)
Example text you may see:
VEHICLE EMISSION CONTROL INFORMATION
TEST GROUP: 3CXYX05.4VKR
ENGINE FAMILY: XYZ123ABC456
DISPLACEMENT: 5.9L
EVAP FAMILY: 3CXYX0145KVT
We need the value labeled TEST GROUP or ENGINE FAMILY.
Tip: Snap a clear phone photo of the entire label and email it to support@norcalcarbmobile.com with your appointment time.
Can’t find it?
Motorhomes and some heavy-duty engines can be tricky. If the label is missing, painted over, or inaccessible:
Check your owner’s manual for a label diagram.
Send us engine bay photos—we can often spot it remotely.
Share your VIN and engine brand—we can request the engine family name from the manufacturer (e.g., Cummins).
Pre-appointment checklist (avoid delays & automatic fails)
✅ Locate and photograph the VECI label (Test Group / Engine Family).
✅ Make sure the area is clean and readable (wipe dust/oil).
✅ Provide VIN and engine make/model if the label isn’t visible.
✅ Have the vehicle parked safely, warmed up, and accessible for SAE J1667 testing.
If the label isn’t visible at time of service, we may not be able to complete the test on-site.
Mobile J1667 smoke opacity testing in Stockton, San Jose, San Francisco and Sacramento regions.
NorCal CARB Mobile provides on-site SAE J1667 opacity tests for motorhomes, fleets, diesel pickups, and commercial vehicles across the Sacramento area, including Roseville, Rocklin, Folsom, Elk Grove, Citrus Heights, Davis, and West Sacramento. We specialize in fast mobile service, compliance guidance, and same-day results when prerequisites are met.
Book or ask a quick question:
📞 916-890-4427 | ✉️ support@norcalcarbmobile.com
FAQs: Engine Family / Test Group & J1667
What if my label says only “Test Group” or only “Engine Family”?
They’re equivalent for our purposes. Send whichever you see.
My RV has a rear engine—where’s the label?
Check the engine cover, air intake, or a panel near the rear service bay. If you still can’t find it, send photos.
Can you test without the Engine Family/Test Group?
We need it in advance. If it isn’t visible, we’ll try to source it using your VIN and engine details, but that may require rescheduling.
Do you test on-site at my home or business?
Yes—mobile SAE J1667 testing across Greater Sacramento. Call to confirm availability for your location and vehicle type.
Call now: 916-890-4427
Email: support@norcalcarbmobile.com
Subject line to use: “J1667 Test – Engine Family Included”
Include in your email: VIN, engine make (e.g., Cummins), and a photo of your VECI label.
