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Schematic and Routing Diagram
EPS System Wiring Circuit DiagramS7RS0B6302001
M
5V
BRNRED/
BLU
BLK
RED
WHT
BLU
GRN
BRN YEL
E52-11
E52-14E52-12
E23-4
E23-26
E23-25 E51-1
E51-2
E52-18
E53-5
E53-7
E52-6
E52-8
E53-2
E52-9
E52-16
E52-19
GRY
PPL/WHT
[A ]
[E ]
12 3
4 5 67
89
11
10
12 13
141516
17 18 19 20
1
2
[B ][C ]
1210 9 8 7654 3 21
16 15 14 13 12 11
26 25 24 2322 21 20 19 18 17
32 31 30 29 28 27
[D]
5V
PPL
E52-4
11
12
13 14
15
10
9
16
12V
5V
5V
12V
REDE52-20E53-6
E53-4
E53-1
7654321
5
REDRED/
BLKWHT
6WHTWHT/BLKWHTBLK
12V
12V
17BLK
GRY
LT GRN
/BLK
E52-1
E52-5
E49-1
GRNGRNWHTBLK
WHY
G28-25G28-31
RED/BLK
18
3
4
4
7 8
4
4
1 2
4
E49-2BLK
I7RS0B630002-01
[A]: Connector “E52” (viewed from harness side) 4. Fuse 12. P/S motor
[B]: Connector “E49” (viewed from harness side ) 5. Left-front wheel speed sensor 13. Shield
[C]: Connector “E51” (viewed from harness side) 6 . Right-front wheel speed sensor 14. Torque sensor
[D]: Connector “G28” (viewed from harness side) 7. Combination meter 15. Torque sensor amplifier
[E]: Connector “E53” (viewed from harness side) 8. “EPS” warning light16. To ECM, BCM, Air bag SDM and ABS control module assembly
1. Main fuse box 9. Date link connector (DLC) 17. ABS/ESP ® control module
2. Ignition switch 10. ECM18. Individual circuit fuse box No.1
3. Junction block assembly 11. P/S control module
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Terminal Arrangement of P/S Control Module Coupler (Viewed from Harness Side)
Diagnostic Information and Procedures
EPS System CheckS7RS0B6304001
WARNING!
Carry out test drive in light traffic area to prevent an accident.
Refer to the following items for the details of each step.Terminal Circuit Terminal Circuit
E49-1 Main power supply for internal memory
and EPS motor E52-9 Ground for torque sensors
E49-2 Ground for P/S control module E52-10 —
E51-1 Motor output 1 E52-11 Serial communication for data link
connector
E51-2 Motor output 2 E52-12 Engine speed signal
E52-1 Ignition switch signal for P/S control
module E52-13 —
E52-2 — E52-14 P/S operation signal (idle up signal)
E52-3 — E52-15 —
E52-4 Vehicle speed signal E52-16 Torque sensor internal failure signal
E52-5 “EPS” warning light E52-17 —
E52-6 Torque sensor signal (Sub) E52-18 Torque sensor signal (Main)
E52-7 — E52-19 Ground for shield wire
E52-8 Main power supply for torque sensor E52-20 5 V reference power supply for torque
sensor
Step
Action YesNo
1 ) Customer complaint analysis
1) Perform customer complaint analysis referring to “Customer Complaint Analysis”.
Was customer complaint analysis performed? Go to Step 2.
Perform customer
complaint analysis.
2 ) DTC check, record and clearance
1) Check for DTC (including pending DTC) referring to “DTC Check”, Record and Clearance.
Is there any DTC(s)? Print DTC or write them
down and clear them by
referring to “DTC
Clearance” and go to
St ep 3 .Go to Step 4.
3 ) Visual inspection
1) Perform visual inspection referring to “Visual Inspection”.
Is there any faulty condition? Repair or replace
malfunction part, and go
to Step 11.
Go to Step 5.
4 ) Visual inspection
1) Perform visual inspection referring to “Visual Inspection”.
Is there any faulty condition? Repair or replace
malfunction part, and go
to Step 11.
Go to Step 8.
5 ) Trouble symptom confirmation
1) Confirm trouble symptom referring to “Trouble Symptom Confirmation”.
Is trouble symptom identified? Go to Step 6.
Go to Step 7.
6 ) Rechecking and record of DTC
1) Recheck for DTC referring to “DTC Check”.
Is there any DTC(s)? Go to Step 9.
Go to Step 8.
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Scan Tool DataS7RS0B6304006
NOTE
When P/S motor is cold condition (that is, armature coil of P/S motor is not heated), normal value with
asterisk (*) mark in the following table is displayed on scan tool.
) C1143 P/S motor circuit current too
high Measured motor drive current is
more than 50 A.
• P/S motor circuit
• P/S motor
• P/S control module1 driving
cycle
) C1145 P/S motor circuit current too
low Measured motor drive current is
less than 2 A continuously for
more than 3 seconds even though
target motor drive current is more
than 4 A.
or
Measured motor drive current is
less than 0.8 A for total 1 second
even though motor control duty is
more than 90% while target motor
drive current is less than 8 A. 1 driving
cycle
) C1153 P/S control module power
supply circuit Power supply voltage of P/S
control module is less than 9 V for
5 seconds continuously. • P/S control module power
supply circuit
• Undercharged Battery
• P/S control module 1 driving
cycle
) C1155 P/S control module internal
failure Internal memory (EEPROM) is
data error.
• P/S control moduleNot
applicable
Internal circuit is faulty.
or
Power supply voltage of P/S
control module exceeded 17.5 V. • Overcharged Battery
• P/S control module
1 driving
cycle
DTC No. Detecting item
Detecting condition
(DTC will set when detecting) Trouble area MIL
Scan tool data
Vehicle conditionNormal condition
) Battery Voltage
Ignition switch ON 10 – 14 V
) TQS Power Supply 10 – 14 V
) TQS Main Torque Engine running at idle speed Steering wheel at fully turned to left –9.4 – 0 N
⋅m
Steering wheel at free 0 N⋅m
Steering wheel at fully turned to right 0 – 9.4 N ⋅m
) TQS Sub Torque Engine running at idle speed Steering wheel at fully turned to left –9.4 – 0 N
⋅m
Steering wheel at free 0 N⋅m
Steering wheel at fully turned to right 0 – 9.4 N ⋅m
) Assist Torque Engine running at idle speed Steering wheel at fully turned to left –9.4 – 0 N
⋅m
Steering wheel at free 0 N⋅m
Steering wheel at fully turned to right 0 – 9.4 N ⋅m
) Motor Control Engine running at idle speed Steering wheel at free
0 A
Steering wheel at fully turned to left or right *35 – 45 A
) Motor Monitor Engine running at idle speed Steering wheel at free
0 A
Steering wheel at fully turned to left or right *35 – 45 A
) Vehicle Speed Engine running and vehicle at stop 0 km/h
) Engine Speed Engine running at idle speed after warming up 700 ± 50 rpm
) Motor Volt Engine running at idle speed Steering wheel at free
0.8 – 1 V
Steering wheel at fully turned to right About 5 V
) Ignition switch Ignition switch ON ON
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Scan Tool Data Definitions
Battery Voltage
This parameter indicates battery positive voltage.
TQS Power Supply (Torque Sensor Power Supply, V)
This parameter indicates the power supply voltage which
the P/S control module supplies to the torque sensor.
TQS Main Torque (Torque Sensor Main Torque, N ⋅m)
The torque sensor is installed to detect the steering force
and the steering directio n. It consists of two
potentiometers and the main torque sensor is one of
these.
TQS Sub Torque (Torque Sensor Sub Torque, N ⋅m)
The torque sensor is installed to detect the steering force
and the steering directio n. It consists of two
potentiometers and the sub-torque sensor is one of
these. Its output characteristics are compared with those
of the main torque sensor.
Assist Torque (N ⋅m)
This parameter is an internal parameter of the P/S
control module. It is obtained by computing the torque
sensor input signal. Motor Control (Motor Control Current, A)
Based on the input signal, the P/S control module
determines the assist amount
and controls the current to
the motor suitable for that a ssist amount. This parameter
indicates that control value.
Motor Monitor (Motor Monitor Current, A)
This parameter indicates the actually measured value of
the current flowing to the motor. The motor circuit
condition is diagnosed by co mparing this parameter with
“Motor Control” parameter described previously.
Vehicle Speed (km/h, MPH)
Vehicle speed signal is fed from BCM. P/S control
module determines the amount of power assist based on
this vehicle speed signal and the torque sensor signal.
Engine Speed (rpm)
Engine speed signal is fed from the ECM so that it can
be used for trouble diagnos is of the electric power
steering system.
Motor Volt (V)
This parameter indicates the voltage between motor
terminals.
Ignition switch (ON, OFF)
This parameter indicates the condition of the power
supply through the ignition switch.
Visual InspectionS7RS0B6304007
Visually check the following pats and system.
P/S System Symptom DiagnosisS7RS0B6304008
This section describes trouble diagnosis of the P/S system parts whose trouble is not indicated by the on-board
diagnostic system (self-diagnostic functi on). When no malfunction is indicated by the on-board diagnostic system
(self-diagnosis function) and those stee ring basic parts as described in “Steering Symptom Diagnosis in Section 6A”
are all in good condition, check the following power steer ing system parts which may be a possible cause for each
symptom of the steering. Inspection Item Referring section
Battery Level, leakage, color “Batte ry Description in Section 1J”
Connectors of electric wire
harness Disconnection friction “Intermittent and Poor
Connection Inspection in Section 00”
Fuses Burning “Cautions in Body Electric al System Servicing in Section 9A”
Parts Installation, damage
Other parts that can be checked visually
Condition Possible cause Correction / Reference Item
Steering wheel feels
heavy (Perform “Steering
Force Check” before
diagnosis.) Steering wheel installed improperly
(twisted)
Install steering wheel correctly.
Poor performance of torque sensor Check torque sensor referring to “Torque
Sensor and Its Circuit Inspection”.
Poor performance of P/S motor Check motor referring to “P/S Motor and Its
Circuit Inspection”.
Steering gear case assembly faulty Replace.
Poor performance of vehicle speed
signal from ECM Check vehicle speed signal circuit referring to
“DTC C1121 / C1123 / C1124: VSS Circuit
Failure”.
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Serial Data Link Circuit CheckS7RS0B6304009
CAUTION!
Be sure to perform “EPS System Check” before starting “Troubleshooting”.
Wiring DiagramVehicle pulls to one side
during straight driving
Poor performance of torque sensor
Check torque sensor referring to “Torque
Sensor and Its Circuit Inspection”.
Steering gear case assembly faulty Replace.
Poor recovery after turns Poor performance of torque sensor Check torque sensor referring to “Torque
Sensor and Its Circuit Inspection”.
Steering column faulty Replace.
Abnormal noise P/S motor (built in steering gear case
assembly) malfunction Replace steering gear case assembly.
No idle up P/S control module faulty Check P/S control module referring to
“Inspection of P/S Control Module and Its
Circuits”.
Condition Possible cause Correction / Reference Item
MBLK
RED
E52-11 E51-1
E51-2PPL/WHT
[A ]
12
3
4 5 67
89
11
10
12 13
141516
17 18 19 2010 9 8 7654 3 21
16 15 14 13 12 11
26 25 24 2322 21 20 19 18 17
32 31 30 29 28 27
[C]
8
79
12V
[B ]
11
12
GRY
LT GRN
/BLK
E52-1
E52-5
E49-1
GRNGRNWHTBLK
WHY
G28-25G28-31
RED/BLK
10
3
4
4
5 6
4
4
1 2
4
E49-2BLK
I7RS0B630003-01
[A]: Connector “E52” (viewed from harness side) 3. Junction block assembly 8. P/S control module
[B]: Connector “E49” (viewed from harness side) 4. Fuse 9. T o ECM, BCM, Air bag SDM control module and ABS control
module assembly
[C]: Connector “G28” (viewed from harness side) 5. Comb ination meter 10. Individual circuit fuse box No.1
1. Main fuse box 6. “EPS” warning light 11. Serial data circuit
2. Ignition switch 7. Date link connector (DLC)
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DTC Detecting Condition and Trouble Area
DTC TroubleshootingDTC detecting condition Trouble area
DTC C1141:
Voltage between both motor drive circuits is more than 8.5
V or less than 0.2 V for 0.5 seconds continuously while
motor is not drived
(1 driving cycle detection logic)
DTC C1142:
Measured motor drive current is more than 10 A as
compared with target motor drive current.
(1 driving cycle detection logic)
DTC C1143:
Measured motor drive current is more than 50 A.
(1 driving cycle detection logic)
DTC C1145:
Measured motor drive current is less than 2 A
continuously for more than 3 seconds even though target
motor drive current is more than 4 A.
or
Measured motor drive current is less than 0.8 A for total 1
second even though motor cont rol duty is more than 90%
while target motor drive current is less than 8 A.
(1 driving cycle detection logic) • P/S motor circuit
• P/S motor
• P/S control module
Step
Action YesNo
1 Was “EPS System Check” performed? Go to Step 2.Go to “EPS System
Check”.
2 DTC check
Is DTC C1153 and/or DTC C1155 indicated together? Go to applicable DTC
diag. flow.
Go to Step 3.
3 Power supply and ground circuit check
1) Check P/S control module power supply and ground
circuit referring to “P/S Control Module Power Supply
and Ground Circuit Check”.
Is it in good condition? Go to Step 4.
Repair or replace
defective circuit.
4 Motor circuit check
1) With ignition switch tuned OFF, disconnect P/S motor
connector (“E51”).
2) Check that P/S motor circuit is as follows. • Insulation resistance of wire harness is infinity between each “P/S motor circuit” terminal and other
terminal at P/S motor connector.
• Wiring harness resistance of each “P/S motor circuit”
is less than 1 Ω.
• Insulation resistance between each “P/S motor circuit” and vehicle body ground is infinity.
• Circuit voltage between each “P/S motor circuit” and ground circuit is 0 – 1 V with ignition switch turned
ON.
Is circuit in good condition? Go to Step 5.
Repair or replace
defective circuit.
5 P/S motor check
1) Check motor and its circuit referring to “P/S Motor and Its
Circuit Inspection”.
Is motor in good condition? Substitute a known-
good P/S control
module, and recheck.
Replace the steering
gear case assembly.
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Voltage Check1) Remove console box.
2) Check for voltage at each terminal with co nnectors connected to the P/S control module.
NOTE
As each terminal voltage is affected by the battery voltage, confirm if the battery voltage is 11 V or
more when ignition switch is ON.
*: The voltage of this circuit may not be checked by voltmeter. If so, use oscilloscope.
Terminal Wire colorCircuit Normal voltage Remarks
E49-1 GRN Main power supply for
internal memory and P/S
motor 10 – 14 V
—
E49-2 BLK Ground for P/S control
module Below 0.3 V
—
E51-1 BLK Motor output 1 *0 – 1 V
↑↓
10 – 14 V
(“Reference
waveform No.1: ”, “Reference
waveform No.2:
”and “Reference
waveform No.3: ”) • Engine idling and steering wheel at
straight position
• Voltage between “E51-1” and vehicle body ground
E51-2 RED Motor output 2 *0 – 1 V
↑↓
10 – 14 V
(“Reference
waveform No.1: ”, “Reference
waveform No.2: ” and “Reference
waveform No.3: ”) • Engine idling and steering wheel at
straight position
• Voltage between “E51-2” and vehicle body ground
E52-1 LT GRN/BLK Ignition switch signal for P/S
control module 10 – 14 V Ignition switch ON
E52-2 — —— —
E52-3 — —— —
E52-4 PPL Vehicle speed signal *0 – 1 V
↑↓
8 – 14 V
(“Reference
waveform No.9”
under “Inspection of
ECM and Its Circuits in Section 1A”.) • Ignition switch ON
•Front left tire tu
rned quickly with right
tire locked
E52-5 GRY “EPS” warning light 0 V “EPS” warning light OFF
E52-6 BLU Torque sensor signal (Sub) About 0 – 2.5 V
• Steering wheel with left turn
• Out put voltage varies linearly
depending on steering force
About 2.5 V Steering wheel at free
About 2.5 – 6 V • Steering wheel with right turn
• Out put voltage varies linearly
depending on steering force
E52-7 — —— —
E52-8 GRN Main power supply for torque
sensor About 12 V• Ignition switch ON
• Check voltage between “E52-8” and
“E52-9” terminals
E52-9 BRN Ground for torque sensors Below 0.3 V —
E52-10 — —— —
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Reference waveform No.1
Motor output signal 1(1), Motor output signal 2(2), with
engine idlingReference waveform No.2
Motor output signal 1(1), Motor output signal 2(2), with
engine idling
Measurement
terminal CH1: “E51-1” to vehicle body ground
CH2: “E51-2” to vehicle body ground
Oscilloscope
setting CH1: 5 V/DIV, CH2: 5 V/DIV
TIME: 20
µs/DIV
Measurement
condition • Engine is idling and steering wheel
at straight position
I6RS0B630017-01
Measurement
terminal CH1: “E51-1” to vehicle body ground
CH2: “E51-2” to vehicle body ground
Oscilloscope
setting CH1: 5 V/DIV, CH2: 5 V/DIV
TIME: 20 µ
s/DIV
Measurement
condition • Engine is idling and steering wheel
is turned to left or right at turning
speed of 90 ° /sec
[A]: Steering wheel is turned left at turning speed of 90 ° /sec
[B]: Steering wheel is turned right at turning speed of 90 ° /sec
[C]: 12 V ON
[D]: GND ON [E]: 1 duty cycle
I6RS0B630018-01