POWER ASSISTED STEERING
Fault finding - Introduction
36B
36B - 2V6 MR-366-X84-36B000$066_eng.mif
PAS
Vdiag No.: 04, 06, 08, 0C
and 12136BPOWER ASSISTED STEERING
Fault finding - Introduction
1. SCOPE OF THIS DOCUMENT
This document presents the fault finding procedure applicable to all computers with the following specifications:
2. PREREQUISITES FOR FAULT FINDING
Documentation type:
Fault finding procedures (this manual):
–Assisted fault finding (integrated into the diagnostic tool), Dialogys.
Wiring Diagrams:
–Visu-Schéma (CD-ROM), paper.
Type of diagnostic tools:
–CLIP + multiplex line sensor
Special tooling required:
3. RECAP
Procedure
To run fault finding on the vehicle's computers, switch on the ignition in fault finding mode (forced + after ignition
feed).
Proceed as follows:
–vehicle card in reader,
–press and hold the Start button (longer than 5 seconds) with the starting conditions not fulfilled,
–connect the diagnostic tool and perform the required operations. Vehicle(s): Mégane II, Scénic IIComputer name: PAS Computer
Program No.: from 8341
Vdiag No.: 04, 06, 08, 0C and 12
Special tooling required
Multimeter
Elé. 1681 Universal bornier
Note (for Mégane II only):
The left-hand and right-hand xenon bulb computers are powered when the dipped headlights are lit. Fault finding
can only be run on them after the ignition has been switched on in fault finding mode (forced + after ignition feed)
and the dipped headlights are on.
DAETRW_V04_PRELI/DAETRW_V08_PRELI/DAETRW_V06_PRELI/DAETRW_V0C_PRELI/
DAETRW_V12_PRELI
MR-366-X84-36B000$066_eng.mif
POWER ASSISTED STEERING
Fault finding - Introduction
36B
36B - 3V6 MR-366-X84-36B000$066_eng.mif
PAS
Vdiag No.: 04, 06, 08, 0C
and 12
To cut off the + after ignition feed, proceed as follows:
–disconnect the diagnostic tool,
–press the start button briefly 2 times (less than 3 seconds),
–confirm that the forced + after ignition feed has been cut off by checking that the computer indicator lights on the
instrument panel have gone out.
Faults
Faults are declared as either present or stored (depending on whether they appeared in a certain context and have
disappeared since, or whether they remain present but have not been diagnosed within the current context).
The present or stored status of faults should be taken into consideration when the diagnostic tool is used following
the + after ignition supply being switched on (without acting on the system components).
For a present fault, apply the procedure described in the Interpretation of faults section.
For a stored fault, note the faults displayed and apply the notes section.
If the fault is confirmed when the instructions in the Notes section are applied, the fault is present. Deal with the fault
If the fault is not confirmed, check:
–the electrical lines which correspond to the fault,
–the connectors on these lines (corrosion, bent pins, etc.),
–the resistance of the component detected as faulty,
–the condition of the wires (melted or cut insulation, wear).
Conformity check
The aim of the conformity check is to check data that does not produce a fault on the diagnostic tool when
inconsistent. Therefore, this stage is used to:
–carry out fault finding on faults that do not have a fault display, and which may correspond to a customer
complaint.
–check that the system is operating correctly and that there is no risk of a fault recurring after repairs.
This section gives the fault finding procedures for statuses and parameters and the conditions for checking them.
If a status is not behaving normally or a parameter is outside the permitted tolerance values, consult the
corresponding fault finding page.
Customer complaints - Fault finding chart
If the test with the diagnostic tool is OK but the customer complaint is still present, the fault should be processed by
customer complaint.
A summary of the overall procedure to follow is provided on the following page in the form of a flow chart.
POWER ASSISTED STEERING
Fault finding - System operation
36B
36B - 7V6 MR-366-X84-36B000$132_eng.mif
PAS
Vdiag No.: 04, 06, 08, 0C
and 12POWER ASSISTED STEERING
Fault finding - System operation
INPUTS OUTPUTS
Vehicle speed signal (sent by the
Anti-lock Braking System computer)
ELECTRIC POWER
ASSISTED
STEERING
COMPUTER
Angle sensor signal (Electronic
stability program signal)
Engine status signal
(running, stopped, actuated
by the starter or stalled)
CAN bus status signal Instrument panel signals
Diagnostic socket
Power supply (permanent +)
Supply (+ after ignition feed) Diagnostic socket
Earth
CAN connection
Wire connection
MR-366-X84-36B000$132_eng.mif
POWER ASSISTED STEERING
Fault finding - System operation
36B
36B - 8V6 MR-366-X84-36B000$132_eng.mif
PAS
Vdiag No.: 04, 06, 08, 0C
and 12
SYSTEM OPERATION
On this vehicle, the steering system is power-assisted by an electric motor (mounted on the steering column). The
driver's actions are translated by a torque sensor, which measures the force applied to the steering wheel by the
driver, and by an angle measuring sensor. The steering wheel angle signal is used by the electronic stability program
computer for the trajectory control programming.
Assistance is provided by means of an electric motor which applies an appropriate torque to the steering column, in
one direction or the other.
A computer controls this assistance according to several vehicle environment parameters, including the vehicle
speed.
NOTE
Depending on the operating conditions and the operations performed on the vehicle before switching on the ignition,
the assistance system may take a certain time to be activated after engine starting; this also applies after battery cut-
off or switching off the ignition.
Fault finding warning lights illumination programming:
Slow flashing of the Service warning light at 2 Hz: the electric power steering system is in fault finding mode.
Rapid flashing of the Service warning light at 8 Hz accompanied by the Check steering message: the steering
wheel angle sensor is not calibrated and not indexed.
Service warning light continuously lit with Check steering displayed on instrument panel: signal received by the
EPAS computer.
–assistance equal to that provided at a speed of 24 mph (40 km/h) if vehicle speed signal is absent or incorrect,
–angle sensor signal invalid: steering wheel angle sensor not calibrated (no active recall).
STOP warning light continuously lit with steering defective displayed on the instrument panel: fault in the EPAS
system.
If the fault is still present after repair, contact the Techline.
Angle sensor programming (initialisation)
The steering wheel angle sensor is initialised after the ignition is switched on. The sensor is not initialised until the
steering wheel has gone through a quarter turn left or right. If this turn is not carried out, the steering wheel angle
value reading will be 1.2 degrees higher or lower than the actual value.
Check consistency of ET020 Steering wheel angle sensor programming. Note:
If the computer detects a fault, the level of assistance can be modified depending on how serious the fault is.
An incorrect or absent vehicle speed signal results in fixed, unsatisfactory assistance.
POWER ASSISTED STEERING
Fault finding - Allocation of computer tracks36B
36B - 9V6 MR-366-X84-36B000$198_eng.mif
PAS
Vdiag No.: 04, 06, 08, 0C
and 12POWER ASSISTED STEERING
Fault finding - Allocation of computer tracks
ALLOCATION OF TRACKS
The computer is inseparable from the steering column assembly
EPAS computer (8-track black connector):
track 1Not used
track 2Not used
track 3Not used
track 4Multiplex line L1 signal
track 5Multiplex line L2 signal
track 6Multiplex line H1 signal
track 7Multiplex line H2 signal
track 8+ after ignition feed
EPAS computer (2-track black connector):
track 1permanent +
track 2earth
MR-366-X84-36B000$198_eng.mif
POWER ASSISTED STEERING
Fault finding - Configurations and programming36B
36B - 11V6 MR-366-X84-36B000$330_eng.mif
PAS
Vdiag No.: 04, 06, 08, 0C
and 12POWER ASSISTED STEERING
Fault finding - Configurations and programming
VP004: STEERING WHEEL ANGLE SENSOR PROGRAMMING
NOTESThis programming procedure is performed after replacing the EPAS computer.
WARNING
Programming the steering wheel angle sensor means programming the 0 angle (wheels straight ahead position).
It must be done for any blank computer, and every time it is requested in this note.
The absence of or incorrect programming of this sensor will illuminate the Service warning light and create an
Electronic Stability Program fault.
OPERATIONS TO PERFORM BEFORE PROGRAMMING
–With the ignition on or engine running (to obtain maximum steering assistance), turn the steering wheel to full
left lock and then to full right lock,
–position the vehicle with the wheels straight ahead and the steering at the centre point (driving in a straight line),
–run the command by pressing the CONFIRM button,
–while the COMMAND IN PROGRESS message is displayed, turn the steering wheel a quarter of a turn from left
to right.
–Once the COMMAND COMPLETE message is displayed, exit fault finding mode (close dialogue with the
computer without switching off the tool) and then switch off the vehicle's ignition for 15 seconds minimum for
the programming to be registered.
Note:
To obtain a precise position with the wheels set straight ahead (driving in a straight line), this operation must be
performed on a front axle adjustment bench (especially for vehicles fitted with ESP).
OPERATIONS TO PERFORM AFTER PROGRAMMING
–Switch on the ignition and establish dialogue with the EPAS computer,
–turn the steering wheel to full left lock and then to full right lock,
–check that the programming has been properly registered: ET020 Steering wheel angle sensor programming
should be STATUS 4,
–check the conformity of the angle value by consulting parameter PR121 Steering wheel angle,
–check that there are no faults,
–carry out the necessary repairs, consulting the fault finding manual.
IMPORTANT
If the vehicle is fitted with ESP, establish dialogue with the ABS/ESP computer after the operation; if the function
is available (depending on computer version) clear the ESP sensor programming using command RZ003.
Make sure there are no ESP faults: make the necessary repairs, consulting the fault finding manual.
MR-366-X84-36B000$330_eng.mif
POWER ASSISTED STEERING
Fault finding - Configurations and programming36B
36B - 12V6 MR-366-X84-36B000$330_eng.mif
PAS
Vdiag No.: 04, 06, 08, 0C
and 12
SC001: COMPUTER CALIBRATION
NOTESThis configuration is performed after replacing the EPAS computer.
WARNING
The computer is supplied with the default calibration 0.
An incorrect configuration may damage the function.
Command SC001 is used to define the vehicle specifications.
The configuration is determined by the following specifications:
–Vehicle type:
–The diameter of the vehicle wheel rims:
–The vehicle engine type and gearbox type:
CALIBRATION PROCEDURE:
–Connect the diagnostic tool and select EPAS,
–select command SC001 Computer calibration,
–configure the computer in line with the vehicle definition,
–exit fault finding mode without switching off the tool (close the application only),
–switch off the ignition,
–wait 15 seconds for the end of power-Iatch then restart,
–make sure that the configuration reading corresponds to the desired calibration:
LC005 or ET026 Computer calibration.
POWER ASSISTED STEERING
Fault finding - Interpretation of faults
36B
36B - 15V6 MR-366-X84-36B000$462_eng.mif
PAS
Vdiag No.: 04, 06, 08, 0C
and 12POWER ASSISTED STEERING
Fault finding - Interpretation of faults
DF002
PRESENT
OR
STOREDCOMPUTER
DEF : Computer fault
WARNING
Consult the fault contexts.
If PR143 Internal fault codes = 46 and the battery voltage when the fault occurs (PR108) is above 9 V, do not
clear the fault; contact the Techline.
If PR143 Internal fault code = 46 and the battery voltage when the fault occurs (PR108) is less than or equal to
9 V, run fault finding on the battery and charge circuit and clear the fault.
For other values of PR143, do not clear the fault, contact the Techline.
NOTESConditions for applying the fault finding procedure to stored faults:
The fault is declared present after starting or a steering wheel movement from full lock
to full lock.
–Check the condition and connection of the battery terminals.
–Check that the EPAS black 2-track connector is correctly locked.
–Check that the EPAS black 8-track connector is correctly locked.
–Check the condition and conformity of the EPAS fuses: on the power fuse board (70A) and on the UPC (5A).
–Check the conformity of PR108 Computer feed voltage: 12 V < PR108 < 16 V.
Check that:
–there is a + 12 V before ignition feed on track 1 of the electric power steering black 2-track connector,
–there is an earth on track 2 of the electric power steering black 2-track connector,
–there is a + 12 V after ignition feed on track 8 of the steering column assembly black 8-track connector.
If there is a repair procedure (see Technical Note 6015A, Repairing electrical wiring, Wiring: Precautions for
repair), repair the wiring, otherwise change the wiring.
If the fault is still present, contact the Techline.
AFTER REPAIRCarry out a road test followed by a complete test with the diagnostic tool.
DAETRW_V04_DF002/DAETRW_V08_DF002/DAETRW_V06_DF002/DAETRW_V0C_DF002/
DAETRW_V12_DF002
MR-366-X84-36B000$462_eng.mif