JAC S2 (Chassis). Service Manual — part 13

Brake Control System

Brake Control System

182

(II) Installation

1. Install the rear wheels’ ABS speed sensor assembly

1). Install the fixing bolt that fixes rear wheels’ speed
sensor

Tightening torque 8~10N.m
△Notice

1. Do not drag the sensor’s harness brutely

2. Mind the gap between speed sensor and signal’s gear

ring

Standard: 0.2~1.1mm

2). Install the fixing point that connects sensor’s
harness and vehicle body, and the three fixing points
that connect with rear torsion beam

3). Connect the harness connector of front wheels’
speed sensor

2. Install the front wheels’ hub
3. Install the railgate’s side panel
4. Install the reargate’s threshold cover
5. Install the tailgate’s threshold cover
6. Install the rear seat’s rotating bracket
7. Install the C column’s trim and decorated

8. Install the rear seat’s backrest
9. Install the rear seat’s cushion
10. Install the rear wheels
11. Connect the negative cable of battery
12. Close the engine hood

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183

VII ESP controller assembly

(I) Disassembly

1. Open the engine hood
2. Disconnect the negative cable of battery
3. Drain the brake fluid, please refer to “brake fluid”
4. Dismantle ESP controller assembly

1). Disconnect the harness connector of ESP controller
assembly

2). Disassemble the oil outlet tube assembly in master
cylinder, front brake pipeline assembly and right-front
brake oil pipe assembly, which are connected to ESP
controller assembly

3). Dismantle the ESP controller’s support and the three
fixing nuts that fix the support

4). Take out the ESP controller

(II) Installation

1. Install the ESP controller

1). Install the three fixing nuts that connect ESP
controller and the support

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2). Install the oil outlet tube assembly in master cylinder,
front brake pipeline assembly and right-front brake oil
pipe assembly, which are connected to ESP controller
assembly

Tightening torque 16~18N.m

3). Connect the harness connector of ESP controller
assembly

2. Add brake fluid, please refer to “brake fluid”
3. Exhaust air from brake system, please refer to “air-removal of brake system”
4. Connect the negative cable of battery
5. Close the engine hood

EPS (Electronic Power Steering)

EPS (Electronic Power Steering)

185

EPS (Electronic Power Steering)

I Brief introduction

(I) Structural introduction

EPS’s structural diagram

1. Steering wheel assembly 3. Steering shaft with universal shaft
2. Steering column assembly 4. Steering gear assembly

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(II) System’s working principle

Diagram of system’s working principle

(III) Maintenance parameter

Project

Standard

Type of manual steering gear

Gear rack

Parameter of steering wheel

φ375mm

Steering column and lower shaft

Crumple level 3

Operating torque of steering wheel

≤ 5N·m

Power steering gear rack’s travel distance

134±1mm

Cord’s transmission ratio

46.82

Steering wheel’s number of turns

2.86±0.04

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(IV) Torque parameter

No. Project

Torque
（N·m）

Remark

1 Steering wheel’s fixing nut

42~52

2 Steering column’s installing nut

20~25

3 Steering column’s installing bolt

20~30

4 Controller support’s fixing bolt

8~10

5 Connecting bolt of steering column assembly and steering shaft

assembly

30~35

6 Connecting bolt of steering shaft assembly and manual steering gear 30~35

7 Primary fixing bolt of manual steering gear

95~105

8 Secondary fixing bolt of manual steering gear

95~105

9 Toe-in adjusting nut of steering tie rod

45~55

10 Slotted nut of steering gear’s external ball

40~50

(V) Maintenance precautions

1. When checking steering system, park the car on dry and level ground
2. All bolts of spare parts in steering system must be tightened with standard torque
3. Check the wheel alignment after finishing the maintenance of steering column assembly, steering
gear and other steering part.
4. The system’s voltage standard is 9~18V.
5. Check the tire’s pressure often and make sure it meets the standard.
6. Once abnormal gap or front-sway appears, confirm which system or assembly the problem exists in,
and solve the problem.
7. Check whether the spare parts of steering system suffer abnormal crash, and replace the broken or
problematic parts immediately
8. It is unacceptable to weld any part of steering gear or system rod piece.
9. Check regularly whether any interference or abrasion is on EPS harness, or whether the connector is
loosen, and replace harness if necessary.

II Failure diagnosis

(I) Chart of diagnostic trouble codes for EPS

No. DTC

Description

1 C1611 Failure happens in torque sensor’s main signal

2 C1613 The difference between primary and secondary circuit of

torque sensor is excessive

3 C1614 Torque sensor’s power failure

4 C1615 Failure of signal in torque sensor’s secondary circuit

5 C1621 Vehicle speed’s signal loss

6 C1622 Wheel speed’s signal loss

7 C1624 Vehicle speed’s reduction exceeds normal level

8 C1641 Motor’s circuit is open or I short-out; drive circuit is

abnormal

9 C1642 Motor’s practical current is far higher than estimated

current

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10 C1643 Motor’s current is too excessive

11 C1645 Motor’s practical current is far lower than estimated current

12 C1651 Angle transducer’s signal is abnormal

13 C1652 Controller’s relay fails

14 C1653 Power voltage is too low

15 C1654 Power voltage is too high

16 C1655 Drive failure (over-temperature, undervoltage)

17 U0073 EPS communication is down

18 U0100 Loss of communication with EMS/ECU

19 U0129 Loss of communication with ABS/BSM

20 C1611 Torque sensor-primary signal’s cross-border

21 C1612 Torque sensor-secondary signal’s cross-border

22 C1613 Torque sensor-sum of primary and secondary signal brakes

limit

23 C1614 Torque sensor-torque sampling overtime

24 C1661 Relay’s circuit is open

25 C1621 Battery’s voltage is too high

26 C1622 Battery’s voltage is too low

27 C1662 Current sensor-mid-current’s calibration error

28 C1663 Current sensor-excessive current

29 C1664 +5VA voltage error

30 C1632 EEPROM data consistency failure

31 C1643 Ignition signal loss

32 C1651 Motor-circuit’s short-out

33 C1667 Temperature sensor-MOSFET overheat

34 C1615 Angle sensor-PWM’s duty-ratio exceeds the limit

35 C1617 Angle sensor-angle’s calculation error

36 C1615 Angle sensor-PWM frequency is abnormal

37 C1616 Angle sensor-P or S signal sampling overtime

38 C1641 CAN- invalid vehicle speed

39 C1641 CAN- vehicle speed sampling is overtime

40 C1642 CAN- invalid wheel speed

41 C1642 CAN- wheel speed sampling is overtime

42 U1000 CAN-BUSOFF

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43 U1000 CAN-message transmission overtime

44 C1665 EPS controller-inside failure

(II) Failure diagnosis

No. Symptom

Failure’s reason

Solution

Remark

1 Vehicle’s deviation

Steering wheel’s ball joint
is loosen or the front
wheel’s alignment is
inappropriate

Adjust the alignment
and ball joint in steering
wheel

Please refer
to ”vehicle’s
steering system
check”

Steering lever system is
broken or suffer excessive
abrasion

Check and adjust each
joint part in steering
system according to the
instructions

Rack’s pre-tightening
degree is in maladjustment.

Adjust or repair the
rack’s pre-tightening
degree in the steering
gear

2

Power-steering is
sporadic or back to
normal after
restarting the engine.

Harness connector is loosen
or in poor contact

Check and reconnect the
connectors, make sure
they are connected
firmly

Please refer
to ”vehicle’s
steering system
check”

Motor’s fuse is loosen or in
poor contact

Re-install the fuse, make
sure it is installed
properly

Motor’s failure

Replace the motor

EPS controller’s failure

Replace the EPS
controller

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(III) Diagnostic flow chart

Flow chart of combination instrument’s EPS warning light keeps lighting, no steering function

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III Vehicle’s steering system check

(I) Check

1. Check the installation

1). Check the installing situation of steering gear assembly, front suspension, axle and steering
column

2). Check whether there is any gap during axial movement

3). Check whether the fixing nuts and bolts of steering gear assembly are loosen

2. Check the free-running distance of steering wheel

1). Turn the steering wheel and keep the front wheels straight ahead. Start the engine, and slightly
turn the wheel left or right, tillthe front wheel starts to move, and measure the steering wheel’s
distance on the excircle

Steering wheel’s free-running distance: 30mm

2). If the measured value exceeds the standard, check the installing situation of all joints of steering
column and the steering assembly, and adjust or replace relevant spare parts if necessary.

3). If the free-running distance still exceeds 30mm, then shut down the engine and keep the front
wheels straight ahead. Apply a force of 5N along the steering wheel’s periphery and check the free-
running distance. If the distance exceeds 10mm, then it is necessary to check whether the steering
assembly is qualified.

4). If the distance still stays at limit, then keep the wheel straight when the engine is dead, apply a
force of 4±0.6N along the wheel’s periphery, and check the free-running distance.

Standard: <15mm

5). If the distance above exceeds the standard, then disassemble the steering gear and check pinion’s
total torque.

3. Check the middle position

1). Confirm whether steering gear assembly, column and
wheel are installed correctly.

2). Carry out middle position check after the front
wheels’ alignment. Please refer to “front wheels’
alignment”

3). Park the vehicle directly, and confirm the steering
wheel is in the middle position.

4). Loosen the locknut of tie rod and turn the adjustment
lever slightly, and confirm whether the steering wheel
still stays at middle position.

4. Check the steering wheel’s static steering force

1). Park the vehicle on dry and level ground, and pull up the brake handle.

2). Start the engine.
△Notice the tire’s pressure should stays in limit

3). Turn the steering wheel a circle from middle position, check the wheel’s steering force, and
whether any apparent fluctuation exists.

steering wheel’s steering force: <34N

acceptable fluctuation: <5.9N

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4). If the steering force exceeds the limit, please check or adjust the following parts:

(1). Check whether the lower suspension arm or steering tie rod’s ball joint is broken

(2). Check the steering gear’s preload and the driving torque of steering tie rod

(3). Check the driving torque of lower suspension arm’s ball joint

5. Check the steering wheel’s self-return

1). Turn the steering wheel for 90°, and drive the vehicle in 35km/h. Keep the speed for several
seconds, and loosen the steering wheel. The auto-return should be at least 70%.
△Notice During slow or sharp turn, check whether the
auto-return in left and right direction is same, by using
personal feeling. This check must be carried out on safe
roads, and keep personal safety as priority

6. Check the front wheels’ steering angle

1). After the toe-in check of front wheel, carry out
steering angle check. When the vehicle is still, and
engine is in idle speed, place the front wheel on steering
angle measurer, and check the maximum steering angle
of inner and external wheels.

Inner wheel: 35.1°±1.5°

External wheel: 30.6°±1.5°
△Notice if the measured value is not in the limit, adjust
the tie rod

7. Steering angle’s adjusting method

1). When the steering angle exceeds the limit, loosen the locknut of left and right steering tie rod, and
use wrench to adjust the tie rod till the angle meets the standard. Then tighten the locknut, and the
tightening torque is 45~55N.m. When re-adjust left and right tie rod, keep the left rod and right rod
equal
△Notice if the inner wheel’s steering angle exceeds limit, adjusting the tie rod to the outside will
increase inner wheel’s angle; when external wheel’s steering angle exceeds limit, adjusting the tie rod
to the outside will reduce external wheel’s angle. The vehicle’s toe-in is relevant to the adjustment of
other four wheels’ alignment and steering angle.

8. Check the dust cover of ball joint

1). Press the cover by fingers to check whether the dust cover is chap or broken

2). If any chap or damage exists on dust cover, replace the tie rod’s ball joint immediately.
△Notice dust cover’s chap or damage on surface may also cause ball joint to suffer damage.

9. Check the tie rod’s ball joint

1). Quickly sway the tie rod for 10 times

2). Use spring scale to measure the swinging resistance of tie rod

Standard: 0.5~3N.m. If the measured value exceeds the limit range, replace tie rod immediately.

IV Steering wheel assembly

(I) Disassembly

1. Open the engine hood

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2. Disconnect the negative cable of battery
△Notice

wait for at least 3 minutes after disconnecting the cable, in case of air bag’s explosion during
disassembly
3. Dismantle driver’s air bag assembly, please refer to
“driver’s air bag assembly”
4. Disassemble the steering wheel assembly

1). Turn the steering wheel, and make sure the front
wheels are on straight line

2). Lock the steering wheel
△Notice make marks before pulling out steering wheel,
and make sure the steering wheel’s position after
installation is the same as the one before.

3). Loosen the fixing nut of steering wheel

4). Pull out the steering wheel from steering shaft
△Notice pre-tighrten the fixing nut to steering wheel,
in case of injuring maintenance personnel when pulling
out the steering wheel
△Notice if the steering wheel cannot be pulled out
manually, it is OK to use professional tools

(II) Installation

1. Install the steering wheel assembly

1). Turn the clock spring clockwise till the stop position,
and turn it 3 circles counter-clockwise

2). Engage the steering wheel to the spline of steering
column
△Notice the locking slot, which is in the bottom of
steering wheel, must match the locating pin of spiral
cable

3). Install the fixing nut and washers

Tightening torque: 42~52N.m

4). Adjust the steering wheel’s steering angle to 0
△Notice after the dismounting of steering column, the wheel’s steering angle may be affected,
while the pilot lamp on dashboard hasn’t lighted. It is necessary to carry out steering wheel’s signal
calibration. After calibration, when the ignition switch is in “ON” position, EPS controller will
inspect each module of the system, and light the EPS pilot lamp. If self-inspection is normal, the pilot
lamp will die in 2 seconds.

2. Install driver’s air bag assembly

3. Connect the negative cable of battery

4. Close the engine hood

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V Steering column assembly

(I) Disassembly

1. Open the engine hood
2. Disconnect the negative cable of battery

△Notice wait for at least 3 minutes after disconnecting
the cable, in case of air bag’s explosion during
disassembly

3. Dismantle driver’s air bag assembly, please refer to “driver’s air bag assembly”
4. Disassemble the steering wheel assembly, please refer to “steering wheel assembly”
5. Disassemble the cladding of steering column, please refer to “cladding of steering column”
6. Disassemble the clock spring, please refer to “clock spring”
7. Dismantle the combination switch, please refer to “combination switch”
8. Dismantle the driver side’s back-plate, please refer to “driver side’s back-plate”
9. Disassemble the guard induction coil, please refer to “guard induction coil”
10. Dismantle the ignition lock assembly, please refer to
“ignition lock assembly”
11. Disassemble the steering column assembly

1). Disconnect the harness connector on steering column

2). Unfix the harness on steering column

3). Loosen the fixing bolt that connects the lower end of
steering column assembly and dashboard skeleton

4). Loosen the two fixing bolts that connect the upper
end of steering column and dashboard skeleton

5). Loosen the fixing bolt that connects steering column
assembly and steering shaft assembly with universl shaft

6). Take off the steering column assembly

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(II) Installation

1. Install the steering column assembly

1). Install the fixing bolt that connects the lower end of
steering column assembly and dashboard skeleton

Tightening torque 20~30N.m

2). Install the two fixing bolts that connect the upper end
of steering column assembly and dashboard skeleton

Tightening torque 20~25N.m

VI Steering shaft assembly with universal shaft

(I) Disassembly

1. Open the engine hood
2. Disconnect the negative cable of battery

△Notice wait for at least 3 minutes after disconnecting
the cable, in case of air bag’s explosion during
disassembly

3. Dismantle driver’s air bag assembly, please refer to “driver’s air bag assembly”
4. Disassemble the steering wheel assembly, please refer to “steering wheel assembly”
5. Disassemble the cladding of steering column, please refer to “cladding of steering column”
6. Disassemble the clock spring, please refer to “clock spring”
7. Dismantle the combination switch, please refer to “combination switch”
8. Dismantle the driver side’s back-plate, please refer to “driver side’s back-plate”
9. Disassemble the guard induction coil, please refer to “guard induction coil”
10. Dismantle the ignition lock assembly, please refer to “ignition lock assembly”
11. Disassemble the steering shaft assembly with universal shaft

1). Loosen the fixing bolt that connects steering column
and steering shaft

2). Loosen the fixing bolt that connects steering shaft
and steering gear

3). Take off the steering shaft assembly with universal
joint

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(II) Installation

1. Install the steering shaft assembly with universal joint

1). Tighten the fixing bolt that connects steering shaft
and steering gear

Tightening torque 30~35N.m

2). Tighten the fixing bolt that connects steering column
assembly and steering shaft assembly

Tightening torque: 30~35N.m

3). Adjust the steering wheel’s steering angle to 0
△Notice after the dismounting of steering column, the
wheel’s steering angle may be affected, while the pilot
lamp on dashboard hasn’t lighted. It is necessary to carry
out steering wheel’s signal calibration. After calibration,
when the ignition switch is in “ON” position, EPS
controller will inspect each module of the system, and
light the EPS pilot lamp. If self-inspection is normal, the
pilot lamp will die in 2 seconds.

2. Install the guard induction coil
3. Install the driver-side back-plate
4. Install the combination switch
5. Install the clock spring
6. Install the steering wheel assembly
7. Install the cladding of steering column
8. Install the driver’s air bag assembly
9. Connect the negative cable of battery
10. Close the engine hood

VII Steering gear assembly

(I) Disassembly

1. Disassemble the left-front wheel, please refer to “wheels”
2. Disassemble the right-front wheel, please refer to
“wheels”
3. Dismantle left-lower suspension arm assembly, please
refer to “lower suspension arm”
4. Dismantle right-lower suspension arm assembly, please
refer to “lower suspension arm”
5. Dismantle the front sub-frame assembly with stabilizer
bar and steering gear, please refer to “front sub-frame

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assembly”
6. Disassemble the steering gear assembly

1). Disassemble the two hex flange-face nuts and two
gear locknuts that connect gear assembly and front
subframe

2). Take off the steering gear assembly

(II) Installation

1. Install the steering gear assembly

1). Put the gear assembly on the installing position of front
sub-frame

2). Install the two hex flange-face nuts and two gear
locknuts that connect gear assembly and front sub-frame

Tightening torque 95~105N.m

3). Adjust the tie rod’s left and right length according to
the value before maintenance, and tighten the locknut
after the adjustment.

Tightening torque 45~55N.m

4). Adjust the steering wheel’s steering angle to 0
△Notice after the dismounting of steering column, the
wheel’s steering angle may be affected, while the pilot
lamp on dashboard hasn’t lighted. It is necessary to carry
out steering wheel’s signal calibration. After calibration,
when the ignition switch is in “ON” position, EPS
controller will inspect each module of the system, and
light the EPS pilot lamp. If self-inspection is normal, the
pilot lamp will die in 2 seconds.

2. Install the front sub-frame assembly with stabilizer bar and steering gear
3. Install the right lower suspension arm assembly
4. Install the left lower suspension arm assembly
5. Install the right-front wheel
6. Install the left-front wheel