Use case
Buying a used car: the pre-purchase report from its ECUs
The pre-purchase report gathers what a used car's ECUs return through the OBD socket (identification, the mileage each one stores, faults, recent clears, consumption and battery) and flags anything that doesn't add up.
Reviewed by Daniel Morales, founder of Reprorace SL, on
Key facts at a glance
| Protocol | Standard | J1962 pins | Speed or link | ECO-LITE | ECO-LITE TOOL | ECOPRO Gen4 |
|---|---|---|---|---|---|---|
| CAN | ISO 15765-4 · ISO 11898 | 6 and 14 (2nd channel on 3 and 11; classic CAN on 1 and 9) | 125, 250 and 500 kbit/s | Yes: 2 channels and pins 1/9 | Reproduces the vehicle's | Multichannel |
| DoIP | ISO 13400 | 3, 11, 12 and 13; activation on 8 | 100BASE-TX (100 Mbit/s) | Yes | Reproduces the vehicle's; Ethernet in PassThru (J2534-2) | Yes |
| K-Line | ISO 9141-2 · ISO 14230 (KWP2000) | 7 | 5-baud or fast initialization | Yes | Reproduces the vehicle's | Yes |
Data from the device catalog and the standards cited. The devices are in pre-production: figures may be adjusted after the first units have been validated.
When you need it
- You're buying a second-hand car and want a technical second opinion
- You value vehicles for resale or accept them as part-exchange
- You suspect the mileage on the instrument cluster isn't the real one
Which Diaglana device covers it, and its limits
- ECO-LITE
- Plugs into the OBD socket of the car you want to buy; the reading is done from the platform and the report flags any inconsistencies.
- What it compares
- The mileage on the instrument cluster against the mileage stored by other ECUs, and engine usage against the mileage.
- Limits
- It only collects what the ECUs store and return. It isn't a mechanical inspection and doesn't replace the roadworthiness test or a professional check.
Questions from professionals about this
How does a repair shop issue a pre-purchase report on a used car?
Who issues the pre-purchase report on a used car, what it contains, how its QR code is verified and what it does not replace: a guide for dealers, appraisers and shops.
What should you check when returning or receiving a leased vehicle?
Before returning a leased vehicle or when receiving one: code scan, monitors, mileage stored in each control unit, battery and damage. Arrive with data and no surprises.
How do you charge for remote diagnostics?
An estimate before you start, online payment or a payment link, and a signed report at the end: how a repair shop organizes billing for remote diagnostics.
For repair shops and professionals: frequently asked questions
Questions drivers ask about this
What should you check before buying a used car with an OBD scanner?
Trouble codes, readiness monitors, freeze frame, battery and live data: what to look at with an OBD scanner before buying a used car, and what it will not tell you.
Can you hide faults by clearing the codes before selling a car?
Clearing codes turns the light off but leaves traces: incomplete readiness monitors, counters since the clear and permanent codes. What a buyer can see.
How can you tell if the odometer has been tampered with?
Signs of odometer tampering: mileage that does not match between control units, invoices and inspections, and wear. What diagnostics can and cannot tell you.
What should you check before selling your car?
Before you sell, read the codes, fix or explain what you find, let the monitors complete, gather invoices and inspections and offer a report: you will sell with more trust.
What should you do if a warning light comes on soon after buying a used car?
You bought a used car and a few days later a warning light comes on: how to read it, what freeze frame and monitors show, what to keep and who to turn to.
Frequently asked questions
Does it detect tampered mileage?
It flags when the mileage doesn't match between ECUs or doesn't fit the engine's usage. It's a sign that needs checking, not proof.
Does the car need to be running?
It doesn't have to be. With the engine running, the reading still works and the report says so.
Does it read every make?
It reads whatever the ECUs return over the device's protocols. Which data each one stores depends on the make and model.
Want to try it in your workshop?
Check the device page for the full specifications, or buy in the shop at the final price.
Keep reading
- Remote OBD diagnostics: what it is, how it works and what it can't do
- K-Line and L-Line (ISO 9141-2 / ISO 14230)
- Fleet remote diagnostics: decide before you take a vehicle off the road
- OBD fault codes: what each one means
- To sign up: the solution: Before buying a used car, ask its control units