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Shock Damping Control (ARC) Operation/Testing
"How-To"

System Operation


The shock damping control feature, provides the selection
of either a firm (sport) suspension tuning or an automatic ride control.
Also included is the electronic variable orifice (EVO) steering control
electronics.

This article contains general hardware diagnostics for
the power steering control valve actuator and shock absorber electronic
system control.

The system is activated using the ride select switch mounted
on the center console to the right of the driver's seat.

With the ride select switch in the FIRM position, the
shock absorber electronic system control adjusts shock absorber damping
to provide a firm (sport) suspension tuning.


With the ride select switch in the AUTO position, the
shock absorber electronic system control adjusts shock absorber damping
to provide a soft ride during normal driving conditions. The shock absorber
electronic system control changes suspension tuning to firm during hard
braking, hard acceleration, cornering or high speed to provide improved
handling.

A FIRM RIDE indicator is provided in the indicator lamp
module. The indicator is illuminated whenever the position is firm. This
includes any time the switch is in the FIRM position or any time the system
switches to the firm tuning in the AUTO switch position.

In the event of a system malfunction, the FIRM RIDE indicator
will flash on and off. Moving the ride select switch between positions
will usually clear any false or intermittent malfunction indications. If
the indicator continues to flash, the system should be checked for possible
malfunction.




In the AUTO mode, the shock damping control system monitors
the following conditions to determine when additional shock damping is
required for improved handling:

  • Brake hydraulic pressure
  • Throttle position Supercharger "boost"
  • Steering wheel angle
  • Vehicle speed

Any one of the following approximate conditions will cause
the shock damping to switch to FIRM:

  • Hard braking: brake hydraulic pressure above 2758 kPa
    (400 psi).
  • More than 90 percent of full throttle.
  • Hard acceleration causing Supercharger "boost".
  • Hard cornering: above 0.35G lateral acceleration.
  • Vehicle speeds above 145 km / h (90 mph).

The shock damping will return to the softer ride a few seconds
after these conditions are no longer present, providing vehicle speed has
dropped below 134 km/ h (83 mph).

Shock Absorber Electronic Steering Sensor Input

An optical shock absorber electronic steering sensor (photo-cell)
has the following characteristics:

  • It is mounted on the steering column tube.
  • It is used to establish the straight-ahead position of
    the steering wheel.
  • Once the shock absorber electronic steering sensor has
    determined this position, it can measure the steering wheel turning angles
    and then calculate the lateral acceleration that results.
  • If the calculated acceleration is greater than predetermined
    values, the shock damping is switched to the firm level of control. This
    input is not used until the vehicle speed is above 19 km / h (12 mph).
  • Once activated, the shocks will remain firm an additional
    seven seconds after the vehicle's speed and/or steering wheel position
    drops below the parameter levels.



Vehicle Speed Sensor Input

The shock absorber electronic system control:

  • Monitors the vehicle speed sensor output to determine
    when the vehicle reaches 145 km/h (90mph).
  • Commands the shock absorber electronic actuator to switch
    from soft ride to firm ride when the vehicle speed reaches 145 km / h (90
    mph) This improves vehicle handling at higher speeds.

Ride Select Switch Input

The shock absorber, electronic system control responds
to the ride select switch to operate in either auto mode or firm ride.
While in firm ride, the shock absorber electronic system control illuminates
the FIRM RIDE indicator.

Headlamp Input

The shock absorber electronic system control responds
to the "Headlamps On" input from the headlamp switch by dimming
the firm ride indicator.

Brake Input

The shock absorber electronic system control:

  • Responds to the brake pressure control valve input.
  • Switches the shock absorber electronic actuators to firm
    when the brake pressure c valve closes to indicate an internal pressure
    2758 kPa (400 psi). This increases control during braking

Acceleration Input

The shock absorber electronic system control responds
to the powertrain control module acceleration signal. This causes the shock
absorber electronic system control to switch the shock absorber electronic
actuators to firm. This improves vehicle handling under hard acceleration
and supercharger boost periods.



Item

Description

1

Shock Absorber Electronic Actuator

2

Data Link Connector (ARC)

3

Powertrain Control Module

4

Brake Pressure Control Valve

5

Ride Select Switch

6

FIRM RIDE Indicator

7

Shock Absorber Electronic System Control

8

Control Relays

9

Rear Shock Absorber

10

Shock Absorber Electronic Steering Sensor

11

Vehicle Speed Sensor

12

Power Steering Control Valve Actuator

13

Front Shock Absorber



Quick Test of ARC system



Pin

Number

Circuit

Circuit Function

1

Not Used

2

873 (Y/BK)

Reference Voltage

3

Not Used

4

209 (W/P)

STI

5

844 (GY/R)

STO

6

Not Used
  1. Gain access to data link (ARC) connector at back of drivers
    side front shock actuator cover. Using a jumper wire connect to a known
    good ground, ground circuit 209 (W/P) Pin 3 at data link connector.
  2. Start engine, run for five seconds Disconnect jumper
    for one second, reconnect ground to Circuit 209 (W/ P). Record DTCs flashed
    on instrument cluster FIRM RIDE indicator. I
  3. Refer to Diagnostic Trouble Code (DTC) Directory
    for proper service procedure per DTCs flashed on instrument cluster
    FIRM RIDE indicator.

NOTE: The following two steps may be repeated as
many times as desired to ensure proper test results. However, once the
engine is turned off or ride select switch is moved, you must start test
over.


NOTE: The lamp will usually turn on before the wheel
has completed the lock turn. This is normal.


  1. With the vehicle at rest and engine running, test the
    steering sensor by turning the steering wheel from lock in one direction
    to lock in the other direction, or until FIRM RIDE lamp turns on. FIRM
    RIDE lamp should turn on for five seconds, then turnoff.
  2. Wait until lamp has turned off from previous-step. Drive
    the vehicle at any desired speed, above 19 km / h (12mph). FIRM RIDE lamp
    should come on and stay on until vehicle speed drops below 19 km / h (12
    mph).
  3. Stop vehicle and turn engine off. Turn the ride select
    switch to the AUTO position. Turn ignition switch to the RUN position.
    Wait until the FIRM RIDE indicator turns off (approximately four seconds).
    FIRM RIDE lamp turns on for four seconds, then flashes a code, refer to
    Diagnostic Trouble Code Directory for proper service procedure.

NOTE: The following two steps may be repeated as
many times as desired to ensure proper test results. However, once the
engine is turned off or ride select switch is moved, you must start test
over.


  1. Ensure ride select switch is in the AUTO position. After
    the FIRM RIDE lamp has turned off , wait five seconds then move ride select
    switch to the FIRM position. After the lamp turns on, wait five seconds
    then turn the ride select switch back to the AUTO position. Repeat this
    test 12 times. FIRM RIDE lamp flashes a code, refer to Diagnostic Trouble
    Code Directory for proper service procedure.
  2. Move the ride select switch to the AUTO position. After
    the FIRM RIDE lamp has turned off press the brake pedal until the FIRM
    RIDE lamp turns on. After the FIRM RIDE lamp turns on, release the brake
    pedal. FIRM RIDE lamp flashes a code refer to Diagnostic Trouble Code Directory
    for proper service procedure.
  3. Ensure ride select switch is in the AUTO position. After
    the FIRM RIDE lamp has turned off, press the accelerator pedal to the floor.
    The FIRM lamp should turn on. After the FIRM RIDE lamp turns on, release
    the accelerator pedal. FIRM RIDE lamp flashes a code, refer to Diagnostic
    Trouble Code Directory for proper service procedure.
  4. Move the ride select switch to the FIRM position. Cycle
    headlamps on and off while observing FIRM RIDE indicator. FIRM RIDE lamp
    should be bright with the headlamps off, and dimmer with the headlamps
    on.

    If test has been completed, then the vehicle has passed
    diagnostics.

    (DTC) DIAGNOSTIC TROUBLE CODE DIRECTORY
(FIRM RIDE Indicator Blinks the Following DTCs Two Times)


Code

Description

All Four Actuator

DTCs Recieved

Concern is in hard or soft damping relay.

11 (1 then 1)

No concern yet.

10 (1)

Concern in LH rear shock absorber electronic actuator.


20 (2)

Concern in RH rear shock absorber electronic actuator.


30 (3)

Concern in RH front .shock absorber. electronic actuator.

40 (4)

Concern in LH front shock absorber electronic actuator.


50 (5)

Short in soft relay.

60 (6)

EVO steering open circuit.

70 (7)

Replace shock absorber electronic system control.

12 (1 then 2)

Soft relay circuitry open/shorted.

13 (1 then 3)

Hard relay circuitry open/shorted.

14 (1 then 4)

Concern in relay control circuitry.

15 (1 then 5)

FIRM RIDE indicator circuit open/ shorted.

16 (1 then 6)

EVO steering circuit short.

22 (2 then 2)

Soft relay short to battery.

23 (2 then 3)

Hard relay short to battery.

25 (2 then 5)

FIRM RIDE indicator short to battery acuator.

26 (2 then 6)

Power steering control valve/switch damaged.

00

Concern is in tester communication circuitry.

If no DTCs are generated as a result of Quick Test,
determine the symptom(s) and refer to Ford service manual.
 
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