The adapter connects the connection cable of the lambda sensor to that of the engine electronics. A plug connection in original design, therefore, is important for transmitting the signal of the lambda sensor to the engine control unit without interference.
The electrical signal of the sensor element is a small voltage between 0 and 1 V with an infinitesimally small measurement current of a few microamperes. The voltage supply of the heating element, however, takes place mainly with battery voltage (12 V); powerful currents of several amperes flow, especially during engine start-up with cold lambda sensor.
The contact elements of the adapter must factor in these different requirements. For reliability reasons, they are often gold plated on the contact side and tinned on the cable connection side. The contact elements must be corrosion-resistant and reliably conduct different currents.
The connection of adapter and cable
An additional important factor is the correct connection of the contact element of the adapter with the cable of the lambda sensor.
This takes place through "crimping", whereby a special tool presses the contact element and cable for a permanent connection. The "crimp height" in this case is of crucial importance for the firm seating of the cable as well as for good electrical conductivity.
The adapter housing guarantees a good seal against water and serves as a safeguard against the loosening of the plug contacts and the opening up of the plug connection. In the process a thermoplastic (plastic) with fibreglass is used in order to provide increased rigidity. Good mechanical and electrical characteristics, resistance to chemicals, resistance to ageing and resistance to high temperatures are the necessary characteristics for this application.
Why an original adapter?
This important mix of different characteristics is only possible with a plug from the original adapter manufacturer who has adapted its products to the requirements of the lambda sensor and its installation position.
As opposed to the use of provisory cable connection of the use of "old adapters", the use of original adapters has the following advantages when replacing the lambda sensor:
- Exact cable length and simple connection to the engine control unit
- No additional tools are required
- No mixing-up of the cables (max. 4)
- Reliability like in a new vehicle
- No additional activities in the car workshop
- NGK/NTK only uses adapters in original design for all lambda sensors.