Preliminaries

1. APPLICABILITY OF THIS DOCUMENT

This document describes the diagnosis applicable to all Electronic Control Units with the following characteristics:

Vehicle(s): MEGANE II and SCENIC II System concerned: ABS

ECU name: ABS BOSCH 8.0 Program no.: 2.3 VDIAG no.: 0C

2. ESSENTIAL ITEMS FOR DIAGNOSIS

Documentation type:

Diagnostic methods (this document):

• Assisted diagnosis (built into the diagnostic tool), paper (Repair Manual or Technical Note), Dialogys.

Wiring Diagrams:

• Visu-Schéma (CD-ROM), paper.

Diagnostic tool type:

• CLIP

Essential tool type:

ESSENTIAL SPECIALIST TOOLS

Multimeter

3. REMINDERS

Faults

There are declared present faults and declared stored faults (which appeared under certain conditions and have since cleared, or are still present but were not diagnosed under the current conditions).

The "present" or "stored" status of faults must be checked when the diagnostic tool is connected after ignition on (+APC), without operating any system components.

For a present fault, deal with the fault following the procedure given in the chapter "Fault interpretation".

For a stored fault, record the displayed faults and follow the instructions in the "Instructions" section.

If the fault is confirmed when the instruction is applied, the fault is present. In this case, repair the fault.

If the fault is not confirmed, carry out the basic checks. To do so, 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 the states and parameters that show no fault on the diagnostic tool when they are inconsistent. This step therefore allows you to:

• diagnosing faults with no fault code displayed 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, treat the problem as a "customer symptom".

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 diagnosed fully with the appropriate tools. The DIAGNOSTIC SHEET, to be completed during diagnosis, provides and keeps a record of the diagnosis performed. It forms part of the communication with the manufacturer. A DIAGNOSTIC SHEET MUST BE COMPLETED EVERY TIME A DIAGNOSIS IS PERFORMED.

This sheet will always be requested:

• When requesting technical assistance from Techline.
• For approval requests, when replacing parts that require mandatory approval.
• To be attached to the "monitored" parts returned. 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 damage or personal injury:

• Check that the battery is correctly charged to avoid damage to the ECUs in case of low charge.
• It is strictly forbidden to carry out a road test with the diagnostic tool in dialogue mode, because the ABS (Anti-lock Braking System) and EBD (Electronic Brake-force Distribution) functions are deactivated. Brake pressure is then identical on both axles of the vehicle (risk of spinning out under hard braking).

7. ABBREVIATIONS GLOSSARY

ABS: Anti-lock Braking System.
+APC: + After contact (ignition on).
+AVC: + Before contact (ignition off).
BVA: Automatic gearbox
COSLAD: Xenon headlamp levelling correction
DAE: Electric power steering
DTC: Diagnostic Trouble Code
REF: Electronic Brake-force Distribution (EBD).
UCH: Passenger compartment unit.
UPC: Protection and switching unit.
VIN: Vehicle Identification Number