sensor ACURA CSX 2006 Service Repair Manual

Restriction on Power Assist Operation
Torque Sensor Neutral PositionHow to Troubleshoot DTCs
17-20EPS Components
General Troubleshooting Information (cont’d)
Repeated extreme steering force, such as turning the
steering wheel continuously back-and-forth with the
vehicle stopped, causes an increase of power
consumption in the EPS motor. The increase of electric
current causes the EPS motor to heat up. Because this
heat adversely affects the system, the control unit
monitors the electric current of the EPS motor.
When the control unit detects heat build-up in the EPS
motor, it reduces the electric current to the EPS motor
gradually to protect the system, and it restricts the
power assist operation. The EPS indicator does not
come on during this function.
When steering torque is not applied to the steering
wheel, or when the ignition is turned to LOCK (0) and
the EPS motor cools, the control unit will restore the
power assist gradually until it’s fully restored (after
about 8 minutes).
The EPS control unit stores the torque sensor neutral
position in the EEPROM. The torque sensor neutral
position must be memorized whenever the gearbox, the
EPS motor, or the EPS control unit is replaced.
NOTE: The torque sensor neutral position is not
effected when erasing the DTCs.
The troubleshooting procedures assume that the cause
of the problem is still present and the EPS indicator is
still on. Following the procedure when the EPS
indicator does not come on can result in incorrect
diagnosis.
1. Question the client about the conditions when the problem occurred, and try to reproduce the same
conditions for troubleshooting. Find out when the
EPS indicator came on, such as while turning, after
turning, when the vehicle was at a certain speed,
etc.
2. When the EPS indicator does not come on during the test-drive, but troubleshooting is done based on
the DTC, check for loose connectors, poor terminal
contact, etc., in the affected circuit before you start
troubleshooting.
3. After troubleshooting, clear the DTC and test-drive the vehicle. Be sure the EPS indicator does not
come on.
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17-22EPS Components
Memorizing the Torque Sensor Neutral Position
A
The torque sensor neutral position must be memorized
whenever the steering gearbox, the torque sensor, the
EPS motor, or the EPS control unit is replaced. Note that
the torque sensor neutral position is not affected when
erasing the DTC.
NOTE: The torque sensor is temperature sensitive.
When memorizing the torque sensor neutral position,
theambienttemperaturemustbeabove20 10°C
(68 18 °F)
1. With the ignition switch in LOCK (0), connect the HDS to the data link connector (DLC) (A) located
under the driver’s side of the dashboard.
2. Turn the ignition switch to ON (II).
3. Make sure the HDS communicates with the vehicle and the EPS control unit. If it doesn’t, troubleshoot
the DLC circuit (see page 11-204).
4. From the EPS MENU, select MISCELLANEOUS TEST, then TORQUE SENSOR LEARN, and follow
the screen prompts on the HDS.
NOTE: See the HDS Help menu for specific
instructions.
5. Turn the ignition switch to LOCK (0).
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DTC Detection Item Note
17-23
DTC Troubleshooting Index
11-01 Low/High IG1-terminal Voltage (Initial Diagnosis)
(see page 17-33)
11-02 Low/High IG1-terminal Voltage (Regular Diagnosis) (see page 17-33)
12-01 Low/High VBU Voltage (Regular Diagnosis) (see page 17-34)
21-01 Excessive Change of the Vehicle Speed Signal (Regular Diagnosis) (see page 17-35)
21-02 Comparison between the Vehicle Speed and the Engine Speed Signal (Regular Diagnosis) (see page 17-35)
22-01 Engine Speed Signal (Initial Diagnosis) (see page 17-37)
31-01 No Writing the Torque Sensor Neutral Position (Initial Diagnosis) (see page 17-22)
32-01 EPS Control Unit Internal Circuit (Current Sensor) (Initial Diagnosis) (see page 17-39)
32-02 EPS Control Unit Internal Circuit (Current Sensor) (Regular Diagnosis) (see page 17-39)
32-07 EPS Control Unit Internal Circuit (Current Sensor) (Steering Diagnosis) (see page 17-39)
32-08 Current Sensor (Regular Diagnosis) (see page 17-40)
32-09 Current Sensor (Initial Diagnosis) (see page 17-40)
33-01 Lower FET Stuck ON (Initial Diagnosis) (see page 17-41)
33-02 Upper FET Stuck ON (Initial Diagnosis) (see page 17-43)
33-06 Lower FET Stuck ON (Regular Diagnosis) (see page 17-41)
33-07 Upper FET Stuck ON (Regular Diagnosis) (see page 17-43)
34-01 Power Relay Stuck ON (Ignition Switch is in LOCK (0)) (see page 17-44)
34-02 Fail-safe Relay Stuck ON (Initial Diagnosis) (see page 17-45)
35-01 EPS Control Unit Internal Circuit (CPU) (Initial Diagnosis/Regular Diagnosis) (see page 17-39)
35-02 EPS Control Unit Internal Circuit (EEPROM) (Initial Diagnosis) (see page 17-39)
35-03 EPS Control Unit Internal Circuit (EPS CPU) (Initial Diagnosis) (see page 17-46)
35-04 EPS Control Unit Internal Circuit (CPU Communication) (Regular Diagnosis) (see page 17-39)
35-05 EPS Control Unit Internal Circuit (EPS Motor/EPS CPU) (Initial Diagnosis) (see page 17-46)
35-06 EPS Control Unit Internal Circuit (ITN Communication) (Regular Diagnosis) (see page 17-39)
35-07 EPS Control Unit Internal Circuit (INHL/INHR Ports) (Initial Diagnosis/ Regular Diagnosis) (see page 17-39)
NOTE:  Initial diagnosis: Done right after the engine starts and until the EPS indicator goes off.
 Regular diagnosis: Done right after the initial diagnosis until the ignition switch is turned to LOCK (0).
 Steering diagnosis: Done during regular diagnosis while turning steering wheel.
(cont’d)
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DTCDetection Item Note
17-24EPS Components
DTC Troubleshooting Index (cont’d)
36-02 EPS Control Unit Internal Circuit (INH Output Circuit) (Initial Diagnosis) (see page 17-39)
37-01 EPS Control Unit Internal Circuit (Step-up Circuit) (Initial Diagnosis) (see page 17-39)
51-01 Low/High Voltage for the Torque Sensor (VT1 and VT2) (Regular
Diagnosis) (see page 17-46)
51-02 Torque Sensor (VT3 Differential-amplification Function) (Regular Diagnosis) (see page 17-50)
51-03 Torque Sensor (VT1, VT2 Rapid-change) (Regular Diagnosis) (see page 17-50)
51-06 Torque Sensor (VT1, VT2 Average) (Regular Diagnosis) (see page 17-50)
51-07 Torque Sensor (VT1, VT2 Initial Check) (Initial Diagnosis) (see page 17-50)
61-04 Open/Short in the EPS Motor Harness (Steering Diagnosis) (see page 17-53)
71-01 EPS Motor Angle Sensor (SIN/COS Signals) (Steering Diagnosis) (see page 17-55)
71-02 EPS Motor Angle Sensor (Neutral Position Learning of SIN/COS) (Initial Diagnosis) (see page 17-55)
71-03 EPS Motor Angle Sensor (SIN/COS Signals) (Steering Diagnosis) (see page 17-55)
71-04 EPS Motor Angle Sensor (Check Signals) (Regular Diagnosis) (see page 17-58)
71-05 EPS Motor Angle Sensor (SIN/COS Signals Charging Amount) (Steering Diagnosis) (see page 17-55)
71-06 EPS Motor Angle Sensor (Neutral Position of SIN/COS) (Initial Diagnosis) (see page 17-55)
NOTE:  Initial diagnosis: Done right after the engine starts and until the EPS indicator goes off.
 Regular diagnosis: Done right after the initial diagnosis until the ignition switch is turned to LOCK (0).
 Steering diagnosis: Done during regular diagnosis while turning steering wheel.
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•••
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EPS Control Unit Inputs and Outputs for Connector D (28P) (Connector disconnected)
Terminalnumber Wire color Terminal sign Description Signal
17-27
NOTE: Standard battery voltage is 12 V.
1WHTCAN-H (CAN-HI) CAN communication circuit
3BLUNEP (Engine pulse) Detects tachometer signal With engine running: pulses
7 BRN SCS (Service check signal) Detects service check
connector signal With service check signal not grounded: battery voltage
8 LT GRN VS2 (Voltage sensor 2) Detects torque sensor
signal
9 BRN PVF (Voltage fade) Drives the torque sensor
10 GRN VS1 (Voltage sensor 1) Detects torque sensor
signal
12 PNK S1 (Signal 1) Detects motor angle sensor
signal
13 BLU R1 (EPS Motor angle
sensor 1) Detects motor angle sensor
signal
14 BRN S2 (Signal 2) Detects motor angle sensor
signal
15 RED CAN-L (CAN-LO) CAN communication circuit
16 YEL GRYIG1
(Ignition 1) Power source for activating
the system With ignition switch ON (II): battery voltage
17 LT BLU K-LINE (Data link connector) Communicates with HDS With service check signal opened: about 5.0 V
26 BRN S3 (Signal 3) Detects motor angle sensor
signal
27 PNK R2 (EPS Motor angle
sensor 2) Detects motor angle sensor
signal
28 BLU S4 (Signal 4) Detects motor angle sensor
signal
1: ’06 model
2: ’07-09 models
(cont’d)
12
Wire side of female terminals
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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
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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´
17-31
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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µ
µ
µ
µ µ
µ
µ
µ
DTC 32-01:
DTC 32-02:
DTC 35-01:
DTC 35-02:
DTC 35-04:
DTC 35-06:
DTC 35-07:
DTC 36-02:
DTC 37-01: DTC 32-07:
YES
NO
YES
NO YES
NO
YES
NO
17-3917-39
EPS Control Unit Internal Circuit
(Current Sensor) (Initial Diagnosis)
EPS Control Unit Internal Circuit
(Current Sensor) (Regular Diagnosis)
EPS Control Unit Internal Circuit
(CPU) (Initial Diagnosis/Regular Diagnosis)
EPS Control Unit Internal Circuit
(EEPROM) (Initial Diagnosis)
EPS Control Unit Internal Circuit
(CPU Communication) (Regular Diagnosis)
EPS Control Unit Internal Circuit
(ITN Communication) (Regular Diagnosis)
EPS Control Unit Internal Circuit
(INHL/INHR Ports) (Initial Diagnosis/Regular
Diagnosis)
EPS Control Unit Internal Circuit
(INH Output Circuit) (Initial Diagnosis)
EPS Control Unit Internal Circuit
(Step-up Circuit) (Initial Diagnosis) EPS Control Unit Internal Circuit
(Current Sensor) (Steering 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.
Go to step 5.
Check for loose terminals or poor connections.
If the connections are good, the system is OK at
this time.
5. Check for DTCs with the HDS.
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). Troubleshoot the indicated DTC. If there are
no DTCs, the system is OK at this time. 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. Turn the steering wheel to the right or left, and wait
10 seconds or more.
Go to step 6.
Check for loose terminals or poor connections.
If the connections are good, the system is OK at
this time.
6. Check for DTCs with the HDS.
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).
Troubleshoot the indicated DTC. If there are
no DTCs, the system is OK at this time.
Does t he E PS i nd i cat or come on?
Is DT C 32-01, 32-02, 35-01, 35-02, 35-04, 35-06,35-07 , 36-02, or 37 -01 ind icated ? Does t he E PS i nd i cat or come on?
Is DTC 32-07 indicated?
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