ELECTRIC POWER STEERING (EPS) ON-BOARD DIAGNOSIS

BHE060201038W02

On-Board Diagnostic (OBD) Test Description

• The OBD test inspects the integrity and function of the EPS and outputs the results when requested by the specific tests.

• On-board diagnostic test also:

– Provides a quick inspection of the EPS usually performed at the start of each diagnostic procedure.
– Provides verification after repairs to ensure that no other faults occurred during service.

• The OBD test is divided into 3 tests:

– Read/clear diagnostic results, PID monitor and record and active command modes.

Read/clear diagnostic results

• This function allows reading or clearing of DTCs in the EPS control module memory.

PID/Data monitor and record

• This function allows access of certain data values, input signals, calculated values, and system status information.

Active command modes

• This function allows control of devices through the WDS or equivalent.

Reading DTCs Procedure

1. Connect the WDS or equivalent to the vehicle DLC-2 connector.

2. Retrieve DTCs using the WDS or equivalent.

Clearing DTCs Procedure

1. After repairs have been made, perform the Reading DTCs Procedure.

2. Clear DTCs using the WDS or equivalent.

3. Verify that the customer's concern has been resolved.

PID/Data Monitor and Record Procedure

1. Connect the WDS or equivalent to the vehicle DLC-2 connector.

2. Access and monitor PIDs using the WDS or equivalent.

Active Command Modes Procedure

1. Connect the WDS or equivalent to the vehicle DLC-2 connector.

2. Activate active command modes using the WDS or equivalent.

DTC Table

DTC

Diagnosis system component

Page

WDS or equivalent

B1318
Battery power supply
(See DTC B1318.)
B1342
EPS control module
(See DTC B1342.)
B2141
EPS system (neutral position setting not performed)
(See DTC B2141.)
B2278
Torque sensor
(See DTC B2278.)
C1099
EPS motor
(See DTC C1099.)
U0073
CAN bus communication error
U1900
CAN communication error
U2023
CAN communication error

PID/DATA Monitor Table

PID Name

(Definition)

Unit/

Condition

Condition/Specification

Action

EPS control module terminal

B+
(System battery voltage value)
V
• IG switch ON: B+
Inspect battery. (See BATTERY INSPECTION.)
Inspect power supply circuit (such as IG switch, fuse).
2P
CCNT
(Number of continuous codes)
-
• DTCs are detected: 1-255
• No DTCs are detected: 0
Perform inspection using appropriate DTC.
-
EPS_MTR
(EPS motor drive signal)
A
• Steering wheel is not turned: Near 0 A
• Steering wheel is turned right: 0-127 A
• Steering wheel is turned left: 0- -128 A
Inspect EPS control module. (See EPS CONTROL MODULE INSPECTION.)
Inspect EPS motor circuit.
Inspect power supply circuit (such as IG switch, fuse).
4A, 4B
EPSLAMP
(EPS warning light output state)
ON/OFF
• EPS warning light is illuminated: ON
• EPS warning light is not illuminated: OFF
Inspect EPS control module. (See EPS CONTROL MODULE INSPECTION.)
Inspect instrument cluster.
-
RPM
(Engine speed signal)
RPM
• Engine speed 1,000 rpm: 1000RPM
Inspect PCM. (See PCM INSPECTION.)
-
TRQ_S_CORR
(System neutral position setting)
NM
• Steering wheel is not turned: Near 0 NM
(If system neutral position setting has not been performed, 31.75 NM is output.)
Perform EPS system neutral position setting. (See EPS SYSTEM NEUTRAL POSITION SETTING.)
-
TRQ_SENS
(Torque sensor signal)
NM
• Steering wheel is not turned: Near 0 NM
• Steering wheel is turned right: 0-31.75 NM
• Steering wheel is turned left: 0- -32 NM
Inspect torque sensor. (See TORQUE SENSOR INSPECTION.)
Inspect torque sensor circuit.
3A, 3B. 3C
VSS
(Vehicle speed signal)
KPH/MPH
• Vehicle is stopped:

0 KPH/0 MPH

• Vehicle speed 20 km/h {12 mph}: 20 KPH/12 MPH
Inspect PCM. (See PCM INSPECTION.)
Inspect instrument cluster. (See INSTRUMENT CLUSTER INSPECTION.)
Inspect DSC HU/CM. (See DSC HU/CM INSPECTION.)
-

Active Command Mode Table

Command Name

Definition

Operation

Note

TRQ_S_CAL
EPS system neutral position setting
ON/OFF
Ignition switch at ON