ACURA CSX 2006 Service Repair Manual

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System Outline
17-28EPS Components
System Description (cont’d)
GAUGE CONTROL MODULE
ECM
Indicator drive signal
EPS CONTROL UNITEPS MOTOR
EPS MOTOR ANGLE SENSOR TORQUE SENSOR Motor drive signal
Motor angle signal Torque signal Idle control
demand
Communication via F-CAN
Vehicle
speed
signal
Engine
speed
signal
The power steering system adopts the electric power steering assisting for the control force of the steering wheel in
the driving force of the electric motor.
The EPS control unit is doing an appropriate steering force control according to the running situation of the vehicle (at
time of low speed, lightness, by the control of emphasis and high-speed running time, control with the steady weight
and the control which will be switched from low speed to high speed smoothly later) by the EPS motor.
The EPS control unit is designed for use with an automotive power steering for the primary purpose of controlling the
assist motor (brushless motor) for the power steering by using as inputs the steering torque signals received from the
‘‘steering torque sensor’’ installed in the steering gearbox as well as the speed signals received from the ‘‘vehicle
speed sensor’’ installed in the vehicle. In addition to the above function, the EPS control unit also provides the failsafe
function, self diagnosis function and motor output limiting function.
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ÎSteering Gearbox
Torque Sensor
17-29
Worm wheel gear
Worm gear
EPS motor
Torque sensor
Steered to right Center Steered to left Steered to left
Steered to right
0 VT1
VT3
VT2
Input voltage (V)
Core
Coil
The EPS motor engages with a pinion and one worm wheel gear, which is transmitted to a direct pinion, to move a
rack.
When the steering wheel is turned, twist occurs in the torsion bar between the steering side of the input shaft and the
output shaft on the road reaction force side. Inductance is changed by the movement of the core. The amount this
voltage changes (varies with the amount of movement, and direction of the core) is amplified with the interface
circuitry of the sensor coil, and output to the EPS control unit as a steer signal.
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17-30EPS Components
Circuit Diagram
BATTERY
GAUGE CONTROL
MODULE (TACH) IGNITION
SWITCH
WHT
UNDER-HOOD
FUSE/RELAY BOX
BRN
BLU UNDER-DASH
FUSE/RELAY BOX
DATA LINK
CONNECTOR (DLC) EPS
INDICATOR
BRN
WHT
RED
BLU
WHT
RED
WHT
RED
ORNLT BLU WHT
ECM/PCM
BRN
3
6 F16
Q9
IG1 HOT in ON (II)
and START (III) D2
B1
H1 YEL*
GRY*
No. 10 (7.5 A)
No. 2 (50 A)
No. 4 (7.5 A)
CAN-H 17
1
19
CAN-L IG1
CAN-H A28
A36
A37
CAN-L NEP
CAN-L 6
14
9
SCS
CAN-H
7
K-LINE
No. 1 (70 A)
No. 1 (100 A)
IG11 2
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17-31
EPS CONTROL UNIT
WHT
BLU
WHT
RED
BRN STEERING GEARBOX
PNK
PNK BLU
BRN GRN
YEL
BLU EPS MOTOR
ANGLE SENSOR
BRN
BLU BLK
BRN
RED
BLU RED GRN
WHT
BLK RED
BLK
GRN
BRN
LT GRN TORQUE
SENSOR
PNK
BLU/RED
WHT/GRN
LT BLU YEL*
GRY*
EPS MOTOR
5V
REGULATOR
FAIL-SAFE
RELAY
POWER RELAY
FAIL-SAFE
RELAY
IG1 VCC
B
A2
IG1 D16
D3
NEP
D1
D15
D7
D17
SCS
CAN-L
CAN-H
K-LINE D13
R2 R1
S3 S1 5
2
4
1
S4 S2 6 3
H-V H-U H-W 2
1
1
PG D12 D27
D26
D14
D28
B1
C1
C2
A1
VS1 D10
PVF D9
VS2 D8
CAN
CONTROLLER R2
R1
S3 S1
S4 S2
H-V H-U
H-W
VS1
PVFVS2 1
2
3
G402
G403
:12V
:5V
*1: ’06 model
*2: ’07-09 models
1
2
(cont’d)
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17-32EPS Components
Circuit Diagram (cont’d)
EPS CONTROL UNIT
CONNECTOR A (2P)
EPS CONTROL UNIT
CONNECTOR B (2P)
DATA LINK CONNECTOR (DLC)
GAUGE CONTROL MODULE (TACH) 36P CONNECTOR
UNDER-DASH FUSE/RELAY BOX CONNECTOR F (34P)
EPS CONTROL UNIT
CONNECTOR D (28P)
EPS CONTROL UNIT
CONNECTOR C (2P) TORQUE SENSOR
3P CONNECTOR
UNDER-DASH FUSE/RELAY BOX
CONNECTOR Q (16P)
UNDER-HOOD FUSE/RELAY BOX
CONNECTOR B (1P)
ECM/PCM CONNECTOR A (44P) EPS MOTOR 1P
CONNECTOR EPS MOTOR 2P
CONNECTOREPS MOTOR ANGLE
SENSOR 6P CONNECTOR
Wire side of female terminals
Wire side of female terminals
Terminal side of male terminals
Terminal side of female terminals
Wire side of female terminals
Wire side of female terminals
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DTC 11-01:
DTC 11-02:
YES
NO YES
NO
17-33
DTC Troubleshooting
EPS CONTROL UNIT CONNECTOR D (28P)
IG1 (YEL)* (GRY)*
*1: ’06 model
*2: ’07-09 models
12
Low/High IG1-terminal Voltage
(Initial Diagnosis)
Low/High IG1-terminal Voltage
(Regular Diagnosis)
1. Turn the ignition switch to ON (II).
2. Clear the DTC with the HDS.
3. Turn the ignition switch to LOCK (0).
4. Start the engine.
5. Wait at least 60 seconds.
Go to step 6.
Check for loose terminals or poor connections.
If the connections are good, the system is OK at
this time.
6. Turn the ignition switch to LOCK (0).
7. Disconnect EPS control unit connector D (28P). 8. Turn the ignition switch to ON (II).
9. Wait at least 60 seconds.
10. Measure the voltage between EPS control unit connector D (28P) terminal No. 16 and body ground.
Check for loose terminals in the EPS control
unit connectors, and repair if necessary. If no poor
connections are found, replace the EPS control unit
(see page 17-84).
If there is no voltage, or the voltage is lower
than specified, repair an open or high resistance in
thewirebetweentheNo.4(7.5A)fuseinthe
under-dash fuse/relay box and the EPS control unit.
If the wire checks OK, check the battery (see page
22-67), and troubleshoot the alternator regulator
circuit (see page 4-28).
Wire side of female terminalsDoes t he E PS i nd i cat or come on?
Is there battery voltage?
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DTC 12-01:
YES
NO
YES
NO
YES
NO YES
NO
YES
NO
17-34
EPS Components
DTC Troubleshooting (cont’d)
B(WHT)
EPS CONTROL UNIT CONNECTOR A (2P) EPS CONTROL UNIT CONNECTOR A (2P)
B(WHT)
Low/High VBU Voltage (Regular
Diagnosis)
1. Turn the ignition switch to ON (II).
2. Check the BATTERY in the EPS DATA LIST with the
HDS.
Check for loose terminals or poor
connections. If the connections are good, the
system is OK at this time.
Go to step 3.
3. Turn the ignition switch to LOCK (0).
4. Check the No. 1 (70 A) fuse in the under-hood fuse/ relay box.
Reinstall the checked fuse, then go to step
13.
Go to step 5.
5. Disconnect the EPS control unit connector A (2P).
6. Check for continuity between EPS control unit connector A (2P) terminal No. 2 and body ground.
Repair short to body ground in the wire
between the EPS control unit and the No. 1 (70 A)
fuse in the under-hood fuse/relay box.
Install a new No. 1 (70 A) fuse in the under-
hood fuse/relay box, then go to step 7. 7. Reconnect the EPS control unit connector A (2P).
8. Turn the ignition switch to ON (II).
9. Clear the DTC with the HDS.
10. Turn the ignition switch to LOCK (0).
11. Start the engine.
12. Check for DTCs with the HDS.
Replace the EPS control unit (see page 17-84).
Troubleshooting is complete. If any other
DTCs are indicated, go to the indicated DTC’s
troubleshooting.
13. Disconnect EPS control unit connector A (2P) and connector D (28P).
14. Measure the voltage between EPS control unit connector A (2P) terminal No. 2 and body ground.
Check for loose terminals in the EPS control
unit connectors, and repair if necessary. If no poor
connections are found, replace the EPS control unit
(see page 17-84).
Repair open in the wire between the EPS
control unit and the No. 1 (70 A) fuse in the under-
hood fuse/relay box.
Wire side of female terminals Wire side of female terminals
Is the voltage at 9.2 17.4 V ?
IsthefuseOK?
Is there continuity? Is DTC 12-01 indicated?
Is there battery voltage?
08/08/21 14:54:03 61SNR030_170_0035
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DTC 21-01:
DTC 21-02:
YES
NO YES
NO
YES
NO
17-35
Excessive Change of the Vehicle
Speed Signal (Regular Diagnosis)
Comparison between the Vehicle
Speed and the Engine Speed Signal (Regular
Diagnosis)
NOTE:
 If the MIL is on, troubleshoot the fuel and emissions systems first.
 Even though the system is operating normally, the EPS indicator will come on caused by the detecting
condition of DTC 21-01 or DTC 21-02 when you raise
the engine speed with the vehicle stopped.
 Clear the DTC related to the ABS/VSA.
1. Turn the ignition switch to LOCK (0).
2. Raise the vehicle, and support it with safety stands in the proper locations (see page 1-11), and allow
all wheels to rotate freely.
3. Connect the HDS to the data link connector (DLC).
4. Turn off VSA by using the VSA OFF switch.
5. Start the engine, run the vehicle in the 4th (M/T), or D position (A/T).
6. Check the VEHICLE SPEED in the EPS DATA LIST with the HDS.
The system is OK at this time.
Go to step 7. 7. Check for DTCs in the fuel and emissions system
(M/T) or A/T system (A/T) with the HDS.
Troubleshoot the indicated DTC(s).
Go to step 8.
8. Start the engine, and check the tachometer.
Go to step 9.
Troubleshoot the gauge control module (tach)
(see page 22-241).
9. Turn the ignition switch to LOCK (0).
10. Short the SCS line with the HDS.
11. Disconnect ECM/PCM connector A (44P) and EPS control unit connector D (28P).
(cont’d)
Is t he v ehi cl e speed i nd i cat ed ? Is DT C P07 20, P07 21, P07 22 or P07 23
indicated?
I s t he t achomet er w or k i ng cor r ect l y ?
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YES
NO
YES
NO
17-36EPS Components
DTC Troubleshooting (cont’d)
EPS CONTROL UNIT CONNECTOR D (28P)
ECM/PCM CONNECTOR A (44P)
CAN-H (WHT)
CAN-H (WHT) EPS CONTROL UNIT CONNECTOR D (28P)
ECM/PCM CONNECTOR A (44P) CAN-L (RED)
CAN-L (RED)
12. Check for continuity between EPS control unit
connector D (28P) terminal No. 1 and ECM/PCM
connector A (44P) terminal No. 36.
Go to step 13.
Repair open in the wire between the EPS
control unit and the ECM/PCM. 13. Check for continuity between EPS control unit
connector D (28P) terminal No. 15 and ECM/PCM
connector A (44P) terminal No. 37.
Check for loose terminals in the EPS control
unit connectors, and repair if necessary. If no poor
connections are found, replace the EPS control unit
(see page 17-84).
Repair open in the wire between the EPS
control unit and the ECM/PCM.
Wire side of female terminals
Terminal side of female terminals Wire side of female terminals
Terminal side of female terminals
I s t her e cont i nui t y ? I s t her e cont i nui t y ?
08/08/21 14:54:04 61SNR030_170_0037
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DTC 22-01:
YES
NO YESNO
17-37
NEP (BLU)
EPS CONTROL UNIT CONNECTOR D (28P)
Engine Speed Signal (Initial
Diagnosis)
NOTE: If the MIL indicator is on, troubleshoot the fuel
and emissions systems first.
1. Turn the ignition switch to LOCK (0).
2. Connect the HDS to the data link connector (DLC).
3. Start the engine.
4. Check the ENGINE SPEED in the EPS DATA LIST with the HDS.
Go to step 5.
The system is OK at this time.
5. Turn the ignition switch to LOCK (0).
6. Disconnect EPS control unit connector D (28P).
7. Start the engine. 8. Measure the voltage between EPS control unit
connector D (28P) terminal No. 3 and body ground.
Check for loose terminals in the EPS control
unit connectors, and repair if necessary. If no poor
connections are found, replace the EPS control unit
(see page 17-84).
Go to step 9.
(cont’d)
Wire side of female terminalsIs t her e 0 r pm at i d l e? I s t her e any v ol t age?
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