2002 HONDA CIVIC Steering

Component Location Index
UNDER.HOODFUSE/RELAY BOX
EPS CONTROL UNITEPS Control Unit Removal/lnstallation,page 17 -67
UNDER.DASH FUSE/RELAY BOX
-,'/.,....
'.,i,
X ]
DATA LINK CONNECTOR I16P)
TOROUE SENSOR
STEERING GEARBOXSteering Gearbox Removal, page 17-51Steering Gearbox Overhaul, page 17-55Steering Gearbox Installation, page 17-63
Removal/lnstallation,page l7-49
GAUGE ASSEMBLY
MOTOR
17-17

EPS Components
aGeneral Troubleshooting Information
EPS Indicator
Under normal conditions, the EPS indicator comes on when
the ignitlon switch is turned to the ON (ll) position, then goes
off after the engine is started. This indicates that the bulb and
its circuit are operating correctly.
lf there is any trouble in the system after the engine is started,
the EPS indicator will stay on, and the power assist is turned
off.
When EPS indicator light comes on, the control unit
memorizes the DTC. In this case, the control unit will not
activate the EPS system after the engine starts again, but it
keeps the EPS indicator on.
When DTC 12, 16, 17, 18 or 67 is stored in the control unit, the
EPS indicator will stay on until the DTC is erased. When a
problem is detected and the EPS indicator comes on, there are
cases when the indicator stays on untilthe ignition switch is
turned 0FF, and cases when the indicator goes off
automatically when the system returns to normal. 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 rapid change in vehicle speed was detected, then. The vehicle (or the vehicle speed sensor signal) stopped for
at least 5 seconds. The engine speed was still 'l,640rpmorhigherforatleastS
seconds
Condition 2:
After the vehicle (or the vehicle speed sensor signal) has
stopped for at least 10 seconds, yet the engine speed was still
1,640 rpm or higherfor at least 20 seconds.
Condition 3:
When the engine speed is 280 rpm or less, and the vehicle is traveling at
a speed of 6,2 mph (10 km/h) or more for 3 seconds.
To determine the actual cause ofthe problem, question the
customer about the conditions during which the problem
occured, taking the above conditions into consideration.
Diagnostic Trouble Code (DTCI
. lf the CPU cannot be activated, or itfails,the EPS indicator
comes on, but the DTC is not memorized.. The memory can hold any number of DTCS. However, when
the same DTC is detected more than once, the most recent
DTC is written over the prior DTC, therefore only one
occurrence is memorized.. The DTCS are indicated repeatedly untilthe ignition switch is
turned OFF.. lf the DTC is not memorized,the EPS indicator blinks.
. The DTCS are memorized in the EEPRO| (non-volatile
memory) therefore the memorized DTCS cannot be erased
by disconnecting the battery. Perform the specified
procedures to clear DTCS.
Self-diagnosis
Self-diagnosis can be classified into two categories:.Initial diagnosis: performed right after the engine
starts and until the EPS indicator goes off.. Regular diagnosis: performed right after the initial
diagnosis until the ignition switch is turned OFF.
The EPS control unit performs the following functions
when a problem is detected by self-diagnosis;
'1. Turns on the EPS indicator.
2. Memorizes the DTC.
3. Stops power assist and manual steering operation
begrns.
NOTE:. When DTC 23 (a problem with the circuit for
engine speed signal) is detected, the power
assist will return to normal when the vehicle
speed is 0.62 mph (1 km/h) or above.. Fot DfCs 22,23, 64, or 66 the EPS indicator goes
off automatically when the system relurns to
normal. For all other codes, the EPS indicator
goes off when the system is OK after the ignition
switch is turned from OFF to ON (ll).
Restriction on Power Assist Operation
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 motor to heat up. Because this heat
adversely affects the system, the control unit monitors
the electric current of the motor.
When the control unit detects heat build-up in the motor,
it reduces the electric current to the 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 off, and the motor
cools, the control unit will restore the power assist
gradually until it's fully restored (after approximately 15
minutes maximum).
17-18

Service Check Signal Circuit Method:
NOTE: Use this procedure when the PGM Tester
software does not match the yearlmodel vehicle you
are working on.
1. With the ignition switch OFF, connect the Honda
PGM Tester (A) to the 16P data link connector {DLC)(B) located under the dash on the driver's side of
the vehicle.
With the vehicle on the ground, set the front wheels
in the straight ahead driving position.
Short the SCS circuit to body ground using the
Honda PGM Tester.
Turn the ignition switch ON (ll). The EPS indicator
comes on for about 6 seconds. Within 4 seconds of
turning the switch ON, while the EPS indicator is on,
turn the steering wheel 45 degrees to the left from
the straight ahead driving position, and hold the
steering wheel in that position until the EPS
indicator goes off.
Within 4 seconds afterthe EPS indicator goes off,
return the steering wheel to the straight ahead
driving position and release the steering wheel.
The EPS indicator comes on again 4 seconds after
releasing the steering wheel,
Within 4 seconds after the EPS indicator comes on,
turn the steering wheel 45 degrees to the left again
and hold it in that position.
The EPS indicator goes off after 4 seconds.
4.
1.Within 4 seconds after the EPS indicator goes off,
return the steering wheel to the straight ahead
driving position again and release the steering
wheel. The EPS indicator blinks twice 4 seconds
after releasing the steering wheel, indicating that
the DTC was erased.
NOTE: If the EPS indicator does not blink twice, an
error was made in the procedure and the DTC was
not erased. Turn the ignition switch OFF, and
repeat the operation from step 3.
Turn the ignition switch OFF afterthe EPS indicator
blinks twice.
9. Disconnect the Honda PGM Tester from the DLC.
10. Perform the DTC code output operation, and be
sure that the code has been erased.
17-21

Symptom Troubleshooting Index
SymptomDiagnostic procedureAlso check fo]
EPS indicator does not
come on
EPS lndicator Circuit Troubleshooting (see page 17-47)
EPS indicator does not go
off and no DTC is stored
EPS Indicator Circuit Troubleshooting (see page 17-47)
EPS indicator does not stay
on, no DTC is stored, and
there is no power assist
1. Check the motor wires between the EPS control unit and the
motor for a short to ground. Repair as needed.
2. lf the motor wires are OK, replace the steering gearbox
{short in the motor).
17-23

EPS Gontrol Unit Inputs and Outputs at Connestor C (20P1
EPS CONTROL UNIT CONNECTOR C (2OP)
Wire side of female terminals
TerminalnumbelWire colorTerminal sign{Terminel name}DescriplionMeasuremeniTerminalsConditions{lqnition switch ON {lll)Voltage
2PNKT/S GND(Torque sensor qround)Ground for the torque
ORNvccl(Voltaqe common 1Power source fortorque3-Groundtartthe enqrneBa$erv voltaqeOV
5YEUBEDVT6(Voltaqe torque 6)Detects torque sensorstonal5 GroundStartthe engine andturn the steerino wheelAbout
YEUBLU(Warninq lamp)Drives the EPS indicatorlidhr6 GroundEPS ONtnotcatol uTl-OVBanerv voltaqe
7BLUAVHTVSP(Vehicle speed pulseiDetects the vehicle speedinput signal for the speedsensor or the ECM (4 pulse/
Raise the vehicle off theground and spin theAlternatingvoltage aboutOV 5V OV-5V
BRNSCS{Servjco check siqnal)Detects service check8-GroundSCS not groundedBattery voltage
10YELIG1llqnition 1Power source for activating10-Groundon switch ON (ll)Batterv voltaqeon switch OFF11G RN//ELvcc2(Voltaqe common 2)Drives the torque sensor1'l-Groundtan the enoineAbout5Von switch OFF8LU/ORNVT3(Voltaoe toroue 3)Detects torque sensor13-GroundStartthe engine andtrrrn the steerino wheelAbout5-0 v
YEUBLKT/SIG(Torque sensor F/SDetects torque sensorsrgnal15-GroundStartthe engineMomentarily 5 V
1'lLT GRN/BI KPSWiPower steerino switch)Provides power steeringswitch sionall7-GroundStartthe engine andnrrn the steerino wheel0-12V
19BLUNEPDetects the engine pulse19-GroundStartthe engine, and let;t idte
20GRYDIAG-HCommunications withHonda PGNI Tester20-GroundPGM Tester not5V
17-25

'I 1.Substitute a known-good EPS control unit, and
connect the all disconnected connectors.
Sta rt the engine.
Does the EPS indicator come on?
YES Go to step 13.
NO Check for loose EPS control unitconnectors. lf
necessary, replace the EPS control unit and
retest.l
Stop the engine, and verify the DTC.
ls DTCl2 indicated?
YES Check for loose torque sensor connectors.
lf necessary, substitute a known-good steering
gearbox and recheck.l
NO-Perform the appropriate troubleshooting for
the code indicated. !
12.
13.
DTC 16: Torque Sensor VT3 and W6
1. Clear the DTC.
2. Start the engine.
3. Wait at least 10 seconds.
Does the EPS indicator come on?
YES Go to step 4.
NO Check for loose wires or poor connnections. lf
the connections are good, the system is OK at this
time.l
4. Stop the engine, and verify the DTC.
ls DTC16 indicated?
YES-Go to step 5.
NO Perform the appropriate troubleshooting for
the code indicated. t
5. Make sure the ignition switch is OFF, then
disconnect EPS control unit connector C (20P) and
the torque sensor 6P connector.
6, Check for continuity between the appropriate EPS
control unit connector C (20P) terminal and body
ground (see table).
Terminal nameEPS control unit connector C
terminal No.
Vccl3
Vcc211
VT313
VT65
T/S GND2
W re s d€ oltemalelermi.als
ls there continuity?
YES- Repair short to body ground in the
appropriate sensor circuit between the torque
sensor and EPS control unit, !
NO Go to step 7.
{cont'd)
EPS CONINOT UNITCONNECIOR C (2OP)
17-29

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.