Preliminaries
1. APPLICABILITY OF THIS DOCUMENT
This document presents the diagnosis applicable to all Electronic Control Units with the following characteristics:
| Vehicle(s): Mégane II System concerned: Electric Power Steering |
ECU name: Electric Power Steering Program no.: from 83 41 VDIAG no.: 0C |
2. ESSENTIAL ITEMS FOR DIAGNOSIS
Documentation type:
Diagnostic methods (this document):
- Assisted diagnosis (integrated in the diagnostic tool), paper (Repair Manual or Technical Notes), Dialogys.
Wiring diagrams:
- Visu-Schéma (CD-ROM), paper.
Diagnostic tool type:
- CLIP
Essential tool type:
ESSENTIAL SPECIALIST TOOLS |
Multimeter |
CLIP |
3. REMINDERS
Procedure
To diagnose the vehicle control units, switch the ignition to diagnostic mode (+ after forced ignition).
Proceed as follows:
- Place the vehicle key on the key holder (vehicles without key scenario 1, entry level, without hands-free and scenario 2, high end, with hands-free),
- press and hold (more than 5 seconds) the "start" button when starting conditions are not met,
- connect the diagnostic tool and carry out the required operations.
Diagnosis is therefore only possible after switching the ignition to diagnostic mode (+ after forced ignition) and switching on the dipped headlights.
To cut the + after ignition supply, proceed as follows:
- disconnect the diagnostic tool,
- briefly press the "start" button twice (less than 3 seconds each time),
- check that the + after ignition supply is cut by the ECU warning lights going out on the instrument panel.
Faults
Declared faults are either present or stored (occurred under certain conditions and have since disappeared, or are always present but not diagnosed under the current conditions).
The present or stored state of faults must be considered when the diagnostic tool is connected after switching on the + after ignition (without operating any components of the system).
For a present fault, apply the fault procedure described in the Fault Interpretation section.
For a stored fault, note the displayed faults and apply the instructions section.
If the fault is confirmed by applying the instruction, the fault is present. Repair the fault.
If the fault is not confirmed, check:
- the electrical circuits corresponding to the fault,
- the connectors of these lines (corrosion, bent pins, etc.),
- the resistance of the component detected as faulty,
- the condition of the wiring (melted or cut insulation, chafing).
Conformity check
The conformity check aims to verify states and parameters that do not show a fault on the diagnostic tool when they are inconsistent. This step therefore allows:
- diagnose faults with no fault display that may correspond to a customer complaint,
- verify correct operation of the system and make sure a fault will not reappear after repair.
This chapter therefore contains a diagnosis of states and parameters, under the conditions required for their check.
If a state does not operate normally or a parameter is out of tolerance, refer to the corresponding diagnostic page.
Customer complaints - Fault locating tree
If the diagnostic tool check is correct but the customer complaint is still present, deal with the problem using "customer effects".
A summary of the overall procedure is shown as a flowchart on the next page.4. DIAGNOSTIC PROCEDURE

5. DIAGNOSTIC SHEET
WARNING: All faults on a complex system must be subject to a full diagnosis using the appropriate tools. The DIAGNOSTIC SHEET, to be completed during diagnosis, provides and keeps a record of the diagnosis performed. It is an essential element of the dialogue with the manufacturer. A DIAGNOSTIC SHEET MUST BE COMPLETED EVERY TIME A DIAGNOSIS IS CARRIED OUT.This sheet will always be requested:
- when requesting technical assistance from the Techline,
- for approval requests, when replacing parts that require mandatory approval,
- to attach it to the “under monitoring” parts requested for return. It is then required for warranty reimbursement and helps with a better analysis of the removed parts.
6. SAFETY INSTRUCTIONS
Any work on a component requires compliance with safety rules to avoid any material or personal injury:
- Check that the battery is correctly charged to avoid damage to the ECUs in case of low charge.
- No smoking.
- Use the appropriate tools.
Test yourself
A quick Renault Megane quiz: every answer comes with an explanation and a link to the manual page.