Products suited to this guided test*
  • PicoBNC+ resistance test lead

  • *At Pico we are always looking to improve our products. The tool used in this guided test may have been superseded and the product above is our latest version used to diagnose the fault documented in this case study.

Charger-vehicle proximity line resistance (type 2)



The information on this page is illustrative. It is not to be used for training purposes or as guidance or instruction. It is also incomplete. A full version of this content can be found in our PicoScope 7 Automotive software, which is downloadable from here.



The purpose of the test is to check the operation and integrity of the Proximity Pilot (PP) line on an Electric Vehicle (EV) having a Type 2 coupling (IEC 62196-2) with the Electric Vehicle Supply Equipment (EVSE).

Charger-vehicle circuit diagram with a Type 2 connector.

Charger-vehicle circuit diagram with a Type 2 connector.

Charger-vehicle circuit with the Type 2 charging lead connected.

Charger-vehicle circuit with the Type 2 charging lead connected.

Further information

The PP line comprises a circuit designed to indicate to the OBC the type of EVSE and charging cable connected to the vehicle.

A connection is made between the vehicle and EVSE by pushing a Type 2 charging cable connector into the vehicle's charging port.

The two are disconnected by removing the charging cable connector from the vehicle's charging port.

The PP line functionality can be checked by disconnecting the PP line between the OBC and the vehicle charging port and measuring the resistance between the PP line (on the vehicle charging port side of the connector) and the vehicle chassis earth.

To complete this test you may need to disconnect connections at the OBC end of the circuit or locate a more accessible connector using the manufacturer's technical information.

In all circumstances, do not carry out a resistance measurement with the Proximity Pilot line intact as there is the potential for harm to the vehicle or your test equipment.

With a Type 2 charging cable connector, the measured resistance will depend on its current capability, as per the following specifications:

Current capability Resistance
13 A 1.5 kilohms
20 A 680 ohms
32 A 200 ohms
63 A (3 phase) / 70 A (single phase) 100 ohms


The resistance values refer to the maximum current rating of the charging connector, meaning the connected EVSE could be capable of a higher charging rate, yet the connector is not. Therefore, the vehicle will only charge at a rate determined by the connector, to prevent overheating.


Symptoms and faults

The resistor circuit is designed to fail to an open state: this will form an open circuit on the PP line, which the OBC will interpret as the removal of the charging connector from the charging port. Hence the OBC will stop charging in this failure mode.

If a Type 2 vehicle does not charge when the charging connector is connected to the vehicle's charging port, it may be necessary to check the connector by directly measuring the resistance across the EVSE charging cable connector's pins, as follows:

  1. If connected, remove the charging cable connector from the vehicle charging port.
  2. Ensure either the charging cable has been removed from the EVSE or mains power to the EVSE has been removed and ensure neither can be reinstated.
  3. When you are totally satisfied that there is no possible way that a voltage can be supplied to the charging cable connector by the EVSE or the vehicle, continue with the next step. If you have any doubts, do not continue.
  4. Locate the PP and PE pins on the Type 2 charging cable connector and connect the resistance lead (using an appropriate method) and the black lead across them. The measured resistance should match that seen at the OBC. If not there may be issues with the wiring between the OBC and the charging port on the vehicle.


This help topic is subject to changes without notification. The information within is carefully checked and considered to be correct. This information is an example of our investigations and findings and is not a definitive procedure. Pico Technology accepts no responsibility for inaccuracies. Each vehicle may be different and require unique test settings.

Help us improve our tests

We know that our PicoScope users are clever and creative and we’d love to receive your ideas for improvement on this test. Click the Add comment button to leave your feedback.

Add comment

Your email address will not be published. Required fields are marked *

Guided test: Charger-vehicle proximity line resistance (type 2)