2003 HONDA CIVIC Workshop Manual

EPS Components
I
7.
8.
DTC Troubleshooting (cont'd)
Turn the ignition switch ON (ll).
Measure the voltage between the appropriate EPS
control unit connector C (20P) terminal and bodyground (see table).
Terminal nameEPS control unit connector C
terminal No.
Vccl3
Vcc211
VT313
VT65
T/S GND2
ls thete battery voltage?
YES Repair shon to power in the + circuit wire
between the EPS control unit and torque sensor.l
NO Go to step 9.
EPS CONTROL UNIT CONNECTOR C {2OP}
Wire side of female terminals
17-30
9.
10.
Turn the ignition switch OFF.
Check for continuity between the appropriate EPS
control unit connector C {20P) terminal and the
torque sensor terminal (see table).
TOROUE SENSOR 6P CONNECTOR
Vccz(GRN/YELI
Wire side offemale terminals
VT6 {YEL/RED)
EPS CONTROL UNITCONNECTOR C I2OP)
VT6 {YEL/RED}
\
Wire side of female terminals
ls there continuty?
YES Go to step 11.
NO Repair open in the appropriate torque sensor
wire circuit between the EPS control unit and the
torque sensor.l
\
Terminal
name
Torque Sensor
terminal No,
EPS control
unit connector
C terminal No.
Vccl23
Vcc2311
VT3'l't3
VT665
T/S GND62
T/S GND {PNK)

11.
't2.
Substitute a known-good EPS control unit, and
reconnect the disconnected connectors.
Sta rt the engine.
Does the EPS indicator come on?
YES Go to step 13.
NO Check for loose or poor connections at the
EPS control unit and the torque sensor conneclors.
lf the connections are good, replace the EPS control
unit and recheck.I
Stop the engine, and verify the DTC.
ls DTC16 indicated?
YES Replace the steering gearbox and recheck.l
NO Perform the appropriate troubleshooting for
the code indicated.l
13.
DTC 17: Torque Sensor Vccl
DTC 18: Torque Sensor Vcc2
1. Clear the DTC.
2. Start the engine.
3. Wait at least 10 seconds.
4.
Does the EPS indicator come on?
YES Go to step 4.
NO Check for loose wires or poor connections. lf
the connections are good, the system is OK at this
time.I
Stop the engine, and verify the DTC.
Is DTCl7 or DTCl8 indicated?
YES Go to step 5.
NO Do the troubleshooting for the DTc
indicated.I
Make sure the ignition switch is OFF, then
disconnect EPS control unit connector C (20P) and
the torque sensor 6P connector.
Check for continuity between EPS control unit
connector C (20P)terminal No. 3 and body ground.
EPS CONTROL UNIT CONNECTOR C (2OP)
Wire side o{ female terminals
ls there continuity?
YES Repair shon to body ground in the wire
between the torque sensor and EPS control unit.I
NO Go to step 7.
(cont'd)
17-31

EPS Components
DTC Troubleshooting (cont'dl
7. Check for continulty between EPS control unit
connector C (20P) terminal No. 3 and the torque
sensor 6P connector terminal No. 2.
EPS CONTROL UNIT CONNECTOR C I2OP)
ls thete continuity?
YES Go to step 8.
NO Repair open in the wire between the torque
sensor and EPS control unit.I
Check for continuity between EPS control unit
connector C (20P) terminal No. 11 and body ground.
EPS CONTROL UNIT CONNECTOR C (2OP)
2356180
lvcc2 {GRN/YEL)
Wire side of female terminals
ls there continuity?
YES Repair short to body ground in the wire
between the torque sensor and EPS control unit. t
NO Go to step 9.
8.
Wire side ol lemale terminals
17-32
\
9. Check for continuity between EPS control unit
connector C {20P) terminal No. 11 and the torque
sensor 6P connector terminal No. 3.
EPS CONTROL UNIT CONNECTOR C (2OP}
Vcc2 (GRN/YEL)
Wire side of female terminals
ls therc continuity?
YES-Go to step 10.
NO Repair open in the wire between the torque
sensor and EPS control unit.l
Substitute a known-good EPS control unit, and
connect all the disconnected connectors.
Sta rt the engine.
Does the EPS indicator come on?
YES Go to step 12.
NO Check for loose or poor connections at the
EPS control unit and the torque sensor connectors.
lf the connections are good, replace the EPS control
unit and recheck.l
Stop the engine, and verity the DTC.
ls DTC17 or DTC18 indicated?
YES-Replace the steering gearbox and recheck.l
NO Perform the appropriate troubleshooting for
the code indicated.l
10.
11.
12.

DTC 22: Vehicle Speed Sensor Signal
DTC 23: Engine Speed Signal
NOTE:. lf the MIL indicator is ON, troubleshoot the PGIVI-Fl
system first.. Even though the system is operating normally, the
EPS indicator will come on under the following
conditions.
- Condition 1:. The vehicle was traveling at least '12.4 mph(20 km/h), then. A rapld change in vehicle speed was detected,
then. The vehicle (or the vehicle speed sensor signal)
stopped for at least 5 seconds, and. The engine speed was still 1,640 rpm or higher for
at least 5 seconds- Condition 2:
After the vehicle (or the vehicle speed sensor
signal) has stopped for at least 10 seconds, yetthe
engine speed was still 1,640 rpm or higher for at
least 20 seconds.- Condition 3:
When the vehicle speed is 10 km/h (6.2 mph) or
above and the engine is running at 280 rpm or
below for 3 seconds.
1. Start the engine and check the tachometer.
ls the tachometer working correctly?
YES- Go to step 2.
NO-Go to step 9.
2. Test-drive the vehicle above 15 km/h {9.3 mph).
ls the speedometer working correctly?
YES Go to step 3.
NO-Perform the speedometer system
troubleshooting {see page 22-651.a
3.Block the rear wheels and raise the vehicle, and
make sure it is securely supported.
Turn the ignition switch ON (ll).
Block the right front wheel, and slowly rotate the
left front wheel, and measure the voltage between
EPS control unit connector C (20P)terminal No.7
and body ground.
EPS CONTROL UNIT CONNECTOR C {2OP)
Does the voltage pulse 0 V and 5 V?
YES Go to step 6.
NO Repair open in the wire between the EPS
control unit and the VSS. lf the wire is OK,check for
a loose or poor connections at the EPS control unit.
lf necessary, substitute a known-good EPS control
unit, and recheck.l
(conr'd)
4.
5.
Wire side of female terminals
17-33

EPS Gomponents
7.
8.
DTC Troubleshooting (cont'dl
Turn the ignition switch OFF, and disconnect EPS
control unit connector C (20P).
Start the engine, and let it idle.
Measure the voltage between EPS control unit
connector C {20P) terminal No.19 and body ground.
EPS CONTROL UNIT CONNECTOR C {2OP)
ls there about 6 V at idle? (With the meter set lol
t requency, is there 33 Hz per 1,000 engine rpm? )
YES Check for loose EPS control unit connectors.
lf necessary, substitute a known-good EPS control
unit and recheck.l
NO Repair open in the wire between the EPS
control unit and the ECM.I
Turn the ignition switch OFF, and disconnect EPS
control unit connector C (20P).
Start the engine, and let it idle.
9.
10.
Wire side of {emale terminals
17-34
11. Measure the voltage between EPS control unit
connector C (20P)terminal No. 19 and body ground.
EPS CONTROL UNIT CONNECTOR C {2OPI
Wire side of female terminals
ls there about 6 V at idle? (With the metet set tor
trequency, is therc 33 Hz per 1,000 engine rpn?)
YES Check for loose EPS control unitconnectors.
lf necessary, substitute a known-good EPS control
unit and recheck.I
NO Go to step '12.
Turn the ignition switch OFF.
Disconnect the ECM connector E (31P) connector.
12.
13.
!

'14. Check for continultv between EPS control unit
connector C (20P)terminal No. 19 and ECM
connector E (31P) terminal No. 26.
ECM CONNECTOR E {31PI
ls thete continuity?
YES-Go to step 15.
NO-Repair open in the wire between the EPS
control unit and ECM.I
Disconnect the gauge assembly 22P connector.
Check for continuity between EPS control unit
connector C (20P)terminal No. 19 and body ground,
EPS CONTROL UNIT CONNECTOR C (2OP}
Wire side of female terminals
ls there continuity?
YES Repair shortto body ground in the wire
between the EPS control unit, the test tachometer
connector, the gauge assembly, and the ECM.I
NO Check for loose ECM control unit connectors.
lf necessary, substitute a known-good ECM control
unit and recheck.I
15.
DTC 37: EPS Control Unit Internal Circuit(lnput Circuit For Motor Voltage)
1. Clear the DTC.
2. Start the engine.
3. Turn the steering wheel from lock-to-lock several
times, and wait 10 seconds or more.
Does the EPS indicator come on?
YES Go to step 4.
NO Check for loose wires or poor connections. lf
the connections are good, the system is OK at this
trme.l
4. Stop the engine, and verify the DTC.
ls DTC 37 indicated?
Y€S Check for loose EPS control unit conneclors.
lf necessary, substitute a known-good EPS control
unit and recheck.l
NO Perform the appropriate troubleshooting for
the code indicated.l
17-35

EPS Components
DTC Troubleshooting (cont'dl
DTC 41: Voltage For Motor
1. Clear the DTC.
2. Start the engine.
3. Turn the steering wheel from lock-to-lock several
times, and wait 10 seconds or more,
Does the EPS indicator come on?
YES-Go to step 4.
NO Check for loose wires or poor connections. lf
the connections are good, the system is OK at this
time.l
4. Stop the engine, and verify the DTC.
ls DTC 41 indicated?
YES Go to step 5.
NO Perform the appropriate troubleshooting for
the code indicated.l
5. Make sure the ignition switch is OFF, then
disconnect EPS control unit connector B (2P) and
the motor 2P conneclor.
6. Check for continuity between EPS control unit
connector B (2P) terminal No. 1 and body ground.
EPS CONTROL UNIT CONNECTOR B {2P}
M1 (RED} HF---t||
Itr(f))
T,L
Wire side of female terminals
ls there continuity?
YES Repair short to body ground in the RED wire
between the EPS control unit and the motor. !
NO-Go to step 7.
17-36
7. Check for continuity between EPS control unit
connector B (2P)terminal No. 2 and body ground.
EPS CONTROL UNIT CONNECTOR B I2P)
TitM2 {GRN) FJ
-r
o)
TI
Wire side of female terminals
ls there continuity?
YES-Repair short to body ground in the GRN wire
between the EPS control unit and the motor,l
NO Go to step 8.
Check for continuity between EPS control unit
connector B (2P)terminal No. 1 and No. 2.
EPS CONTROL UNIT CONNECTOR B {2P)
Wire side of female terminals
ls there continuity?
YES Repair short between the RED and GRN
wires in the motor circuit between the EPS control
unit and the motor.l
NO Go to step 9.
M2 (GRNI
.l
\

9. Turn the ignition switch ON (ll), and measure the
voltage between EPS control unit connector B (2P)
terminal No. 1 and body ground
EPS CONTROL UNIT CONNECTOR B (2P)
M1 IREDI Hr-_ -1 ||
tr,<.)\uL,/Y
I
Wire side oI female terminals
Is there battety voltage?
YES Repair short to power in the + circuit wire
between the EPS control unit and the motor.I
NO-Go to step 10.
Measure the voltage between EPS control unit
connector B (2P)terminal No.2 and body ground.
EPS CONTROL UNIT CONNECTOR B (2P)
10.
raz rcnrrrr l{l-t . I
I(v)
YI
Wire side of female terminals
ls there battery voltage?
YES-Repair shortto power in the - circuitwire
between the EPS control unit and the motor.!
NO Go to step 11.
11.Turn the ignition switch is OFF.
Substitute a known-good EPS control unit, and
connect all the disconnected connectors.
Start the engine, and turn the steering wheel from
lock to lock several times.
Does the EPS indicator come on?
YES-Go to step 14.
NO-Check for loose or poor connections atthe
EPS control unit and the motor connections. lfthe
connections are good, replace the EPS control unit
and recheck.l
Stop the engine, and verity the DTC.
ls DTC 41 ind icated?
YES Replace the steering gearbox motor and
recheck.l
NO Perform the appropriate troubleshooting for
the code indicated.l
13.
14.
17-37