OBD1 to OBD2: diagnostics on older vehicles
The standardised 16-pin OBD2 socket is standard today – in the EU it became mandatory for new vehicles with petrol engines from 2001 and with diesel engines from 2004. Older vehicles, on the other hand, often have manufacturer-specific diagnostic connectors: round, square, with 2, 10, 20 or 38 contacts. A modern diagnostic tool does not fit them mechanically. The solution is an OBD1-to-OBD2 adapter cable – with it, you can keep using your existing diagnostic tool on youngtimers and older vehicles.
When do you need an OBD1 adapter?
- The vehicle has no trapezoidal 16-pin socket in the footwell or under the dashboard.
- Instead, there is a round or rectangular manufacturer connector in the engine compartment, in the fuse box or under the centre console.
- Your diagnostic tool supports the vehicle in principle but cannot be connected because there is no suitable socket.
Tip: Before ordering, count the contacts on the vehicle connector and note its shape. The pin count is the most reliable feature for choosing the right cable.
Important: An adapter cable is not a diagnostic tool. It only provides the mechanical and electrical connection between the vehicle and the diagnostic tool. Which control units and functions you can reach always depends on the diagnostic tool used, its software and the manufacturer, model and model year of the vehicle.
Depending on the connector, the vehicle port does not always supply power. In that case, the diagnostic tool must be powered separately – check this in your device's manual.
Overview: which OBD1 adapter fits which brand?
| Brand | Diagnostic connector on the vehicle | Suitable adapter cable |
|---|---|---|
| BMW | 20-pin, round | BMW 20-pin to OBD2 |
| Chrysler | 6-pin | Chrysler 6-pin to OBD2 |
| Chrysler | 12+8-pin | Chrysler 12+8-pin to OBD2 |
| Fiat | 3-pin | Fiat 3-pin to OBD2 |
| Ford | 7-pin | Ford 7-pin to OBD2 |
| GM | 12-pin | GM 12-pin to OBD2 |
| Honda | 3-pin | Honda 3-pin to OBD2 |
| Hyundai | 12-pin | Hyundai 12-pin to OBD2 |
| Kia | 20-pin | Kia 20-pin to OBD2 |
| Mazda | 17-pin | Mazda 17-pin to OBD2 |
| Mercedes-Benz | 38-pin, round | Mercedes 38-pin to OBD2 |
| Mercedes Sprinter | 14-pin | Sprinter 14-pin to OBD2 |
| Nissan | 14-pin | Nissan 14-pin to OBD2 |
| Opel | 10-pin | Opel 10-pin to OBD2 |
| Porsche | 19-pin, round | Porsche 19-pin to OBD2 |
| Renault | 12-pin | Renault 12-pin to OBD2 |
| Subaru | 9-pin | Subaru 9-pin to OBD2 |
| Toyota | 17-pin | Toyota 17-pin to OBD2 |
| Toyota | 22-pin | Toyota 22-pin to OBD2 |
Everything in one case: the Autel OBD1 adapter set
If you regularly service older vehicles of different brands, a complete set is your best choice. The original Autel adapter case contains the common connectors for VAG 2x2-pin, Mercedes-Benz 38-pin, Mercedes Sprinter/VW LT 14-pin, BMW 20-pin, Fiat 3-pin, Peugeot/Citroën 2-pin, Opel/GM/Daewoo 12-pin, Honda 3-pin, Nissan 14-pin, Mitsubishi/Hyundai 12/16-pin and Kia 20-pin. According to the manufacturer, the set fits many Autel diagnostic systems, from the MaxiDAS DS808 series through the MaxiSys MS906, MS908, MS909 and MS919 to the MaxiSys Ultra.
The most important individual cables
Opel 10-pin to OBD2
For older Opel models with the typical 10-pin diagnostic connector.
BMW 20-pin to OBD2
For BMW models with the round 20-pin connector in the engine compartment. Note: this is the version with an OBD2 socket – for Bosch KTS we stock a separate variant with banana plugs.
Mercedes 38-pin to OBD2
For Mercedes-Benz vehicles with the round 38-pin diagnostic connector.
Mercedes Sprinter 14-pin to OBD2
For the first-generation Sprinter with a 14-pin connector.
Fiat 3-pin to OBD2
Ford 7-pin to OBD2
Toyota 17-pin to OBD2
Honda 3-pin to OBD2
Renault 12-pin to OBD2
Porsche 19-pin to OBD2
GM 12-pin to OBD2
Conclusion
With the right OBD1 adapter, your diagnostic tool is ready for use on older vehicles too – without a special solution. For individual brands, the matching single cable is enough; multi-brand workshops are fully equipped with the Autel adapter case. You can buy on invoice via Klarna or PayPal.
You will find all cables in the OBD adapter cables category. Read more about the standardised socket in our article OBD connector: all questions and answers. Questions? 0711-3654 4645.