Repair assistance

CHANGES IN DIAGNOSIS ON THE MEGANE II

• A help function for detecting a faulty control unit or segment:

In the event of a total failure of the multiplex network, this command isolates network segments, which rules out the segments that respond correctly to the tool. This makes it easier to locate the source of the fault.

The fault location assistance algorithm is designed to handle electrical faults on the CAN only. Connectors and control units that are not connected to the bus must not be taken into account.

• A check using physical measurements for multiplex network faults:

When a segment of the multiplex network is short-circuited, the control units can no longer communicate with each other or with the diagnostic tool. In this case, the network test is unavailable.

The CLIP tool can determine some types of fault through electrical measurements on the CAN H and CAN L multiplex network. It can detect: a CAN L / CAN H short circuit, a CAN L / +12 V short circuit, a CAN H / +12 V short circuit, a CAN H / ground short circuit.

Then, by following the connector and control unit disconnection sequence described in the section “fault segment / control unit detection aid”, the segment responsible for the multiplex network fault can be identified or suspected.

• Disconnecting connectors and control units:

⇒ “Network fault location aid” screen

Following the diagnostic tool algorithm and depending on the results obtained during the procedure, the disconnection sequence for connectors and control units recommended by the diagnostic tool is as follows: Injection, ABS, UPC (Protection and Switching Unit), Automatic gearbox (BVA), LPG, Steering column lock, Electric power steering, Instrument panel, UCH (Passenger Compartment Central Unit), Air conditioning, Control and switching unit, R369 connector, Driving school box, Airbag, R2 connector, Automatic parking brake, Roof control unit.

NOTE: The tool sometimes asks you to disconnect control units that are not fitted to the vehicle being serviced. In this case, the user must check that the control unit in question is absent, validate as if the disconnection and reconnection had been carried out on that component, and continue the test.

“Network physical measurements” screen

Using the second screen, the operator can check the state of the multiplex network after each disconnection and reconnection of the connector or control unit of their choice. This allows the operator to check the state of the multiplex network after each component is disconnected.