ON-BOARD DIAGNOSTIC SYSTEM [ELECTRIC POWER STEERING (EPS)]

id0602001009a1


Outline

•  The on-board diagnostic system consists of a malfunction detection system that detects abnormalities in input/output signals when the ignition switch is ON, a data monitor function that reads out specified input/output signals.
•  The data link connector 2 (DLC-2), which groups together all the connectors used for malfunction diagnosis into a single location, has been adopted, thereby improving serviceability. Diagnosis is performed by connecting the Mazda Modular Diagnostic System (M-MDS) to the DLC-2.
•  In addition to DTC read-out, the Mazda Modular Diagnostic System (M-MDS) is used to clear DTCs using the display screen of the diagnostic tester, and to access the PID/data monitor, providing enhanced malfunction diagnosis and improved serviceability.

Block diagram

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Function


Malfunction detection function

•  The malfunction detection function detects malfunctions in the input/output signal system of the EPS control module when the ignition switched ON or driving the vehicle.


Malfunction display function

•  When the malfunction detection function detects a malfunction, the power steering malfunction indicator light illuminates or flashes to advise the driver. Using the external tester communication function, DTCs can be output to the DLC-2 via the CAN line. At the same time, malfunction detection results are sent to the memory and fail-safe functions.
•  The power steering malfunction indicator light may not illuminate depending on the detected malfunction.


Memory function

•  The memory function stores DTCs of malfunctions in input/output signal systems. With this function, once a DTC is stored it is not cleared after the ignition switch has been switched off, even if the malfunctioning signal system has returned to normal.
•  Since the EPS control module has a built-in non-volatile memory, DTCs are not cleared even if the battery is removed. Therefore, it is necessary to clear the memory after performing repairs. Refer to the Workshop Manual for the DTC clearing procedure.

DTC table

DTC

Power steering malfunction indicator light illumination status

Diagnosis system component

Fail-safe

Drive cycle

Self test type*1

Memory function

M-MDS
C200B:02
Illuminated/Indication
Torque sensor
×
—
C, D
×
C200B:16
Illuminated/Indication
Torque sensor
×
—
C, D
×
C200B:1C
Illuminated/Indication
Torque sensor
×
—
C, D
×
C200B:62
Illuminated/Indication
Torque sensor
×
—
C, D
×
C200B:64
Illuminated/Indication
Torque sensor
×
—
C, D
×
C200B:85
Illuminated/Indication
Torque sensor
×
—
C, D
×
C200C:1C
Illuminated/Indication
Torque sensor
×
—
C, D
×
C200D:1C
Illuminated/Indication
EPS motor
×
—
C, D
×
C200D:64
Illuminated/Indication
EPS motor
×
—
C, D
×
U0001:88
Illuminated/Indication
CAN system communication error
×
—
C, D
×
U0100:00
Illuminated/Indication
Communication error to PCM
×
—
C, D
×
U0121:00
—
Communication error to DSC HU/CM
×
—
C, D
×
U0126:00
—
Communication error to SAS control module
×
—
C, D
×
U0155:00
—
Communication error to instrument cluster
×
—
C, D
×
U0214:00
—
Communication error to start stop unit
×
—
C, D
×
U023A:00
—
Communication error to forward sensing camera (FSC)
×
—
C, D
×
U0338:00
—
Signal error from start stop unit
×
—
C, D
×
U0401:00
Vehicle speed signal error
•  Illuminated/Indication
Engine speed signal error
•  —
i-stop condition signal error
•  —
Signal (vehicle speed) error from PCM
×
—
C, D
×
U0415:00
—
Signal error from DSC CM
×
—
C, D
×
U0423:00
—
Signal (engine switch status) error from instrument cluster
×
—
C, D
×
U0428:00
—
Signal error to SAS control module
×
—
C, D
×
U0515:00
—
Signal error from start stop unit
×
—
C, D
×
U053B:00
Illuminated/Indication
Signal error to forward sensing camera (FSC)
×
—
C, D
×
U053B:61
Illuminated/Indication
Forward sensing camera (FSC)
×
—
C, D
×
U053B:82
Illuminated/Indication
Signal error to forward sensing camera (FSC)
×
—
C, D
×
U053B:83
Illuminated/Indication
Signal error to forward sensing camera (FSC)
×
—
C, D
×
U2011:19
Illuminated/Indication
EPS motor
×
—
C, D
×
U2011:1C
Illuminated/Indication
EPS motor
×
—
C, D
×
U2011:62
Illuminated/Indication
EPS motor
×
—
C, D
×
U2011:72
Illuminated/Indication
EPS motor
×
—
C, D
×
U2011:92
Illuminated/Indication
EPS motor
×
—
C, D
×
U2300:54
—
EPS configuration
×
—
C, D
×
U2300:55
Illuminated/Indication
EPS configuration
×
—
C, D
×
U2300:56
—
EPS configuration
×
—
C, D
×
U3000:16
Illuminated/Indication
EPS CM
×
—
C, D
×
U3000:1C
Illuminated/Indication
EPS CM
×
—
C, D
×
U3000:28
Illuminated/Indication
EPS CM
×
—
C, D
×
U3000:41
Illuminated/Indication
EPS CM
×
—
C, D
×
U3000:46
—
EPS CM
×
—
C, D
×
U3000:47
Illuminated/Indication
EPS CM
×
—
C, D
×
U3000:49
Illuminated/Indication
EPS CM
×
—
C, D
×
U3000:4B
—
EPS CM
×
—
C, D
×
U3000:61
Illuminated/Indication
EPS CM
×
—
C, D
×
U3000:73
Illuminated/Indication
EPS CM
×
—
C, D
×
U3000:96
Illuminated/Indication
EPS CM
×
—
C, D
×
U3003:16
Illuminated/Indication
Battery power supply
×
—
C, D
×
U3003:17
Illuminated/Indication
Battery power supply
×
—
C, D
×

*1  :C: CMDTC self test, D: ODDTC self test
Status byte for DTC
•  The status byte is the two-digit code (two digits after hyphen (-)) after the DTC.
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•  The status byte is a code which indicates the pending code, current/past malfunction status, or warning illumination status.
•  The status byte can be read by performing a CMDTC self test using the Mazda Modular Diagnostic System (M-MDS).
•  For details on the status byte, refer to the explanation on the M-MDS when reading the DTC.
DTC 7-digit code definition
•  When related systems or components have failed, the CM stores the DTC of the malfunctioning part in the CM memory, and allows for the retrieval of the store data using scanning tool when necessary. The DTCs are indicated using seven digits. Each digit indicates the following.
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Fail-safe function

•  When the malfunction detection function determines a malfunction, the power steering malfunction indicator light illuminates to advise the driver. At this time, the fail-safe function disables system control or gradually reduces the assist power.

DTC

Fail-safe control status

M-MDS
C200B:02
Control disabled
C200B:16
Control disabled
C200B:1C
Control is maintained in the backup control
C200B:62
Control disabled
C200B:64
Inhibits normal control, switches to backup control, and controls electric power steering so that steering assist can be maintained
C200B:85
Control disabled
C200C:1C
Control is maintained in the backup control
C200D:1C
Control is maintained in the backup control
C200D:64
Control disabled
U0001:88
Control enabled
U0100:00
Control is maintained in fail mode by gradually changing controlled vehicle speed
U0121:00
Control enabled
U0126:00
Control enabled
U0155:00
Control enabled
U0214:00
Control enabled
U023A:00
Control enabled
U0338:00
Control enabled
U0401:00
•  Vehicle speed signal error
―  Control is maintained in fail mode by gradually changing controlled vehicle speed
•  Engine speed signal error
―  Control enabled
•  i-stop condition signal error
―  EPS i-stop control is not performed, and normal control is maintained
U0415:00
Control enabled
U0423:00
•  Control enabled
―  If the EPS CM detects the signal that a engine speed is below the specified value, it disables assistance
U0428:00
Control enabled
U0515:00
Control enabled
U053B:00
Control enabled
U053B:61
Control enabled
U053B:82
Control enabled
U053B:83
Control enabled
U2011:19
Control disabled
U2011:1C
Control disabled
U2011:62
Control disabled
U2011:72
•  An open circuit malfunction is detected in the one phase of the three-phase stator in the EPS motor
―  Control is maintained in the backup control
•  Other malfunction detected in EPS motor internal circuit
―  Control disabled
U2011:92
Control disabled
U2300:54
Control enabled
U2300:55
Control enabled
U2300:56
Control enabled
U3000:16
Control disabled
U3000:1C
Control disabled
U3000:28
Control disabled
U3000:41
Control disabled
U3000:46
Control is maintained in fail mode
U3000:47
Control disabled
U3000:49
Control disabled
U3000:4B
Control is maintained in fail mode
U3000:61
Control disabled
U3000:73
Control disabled
U3000:96
Control disabled
U3003:16
•  Control is maintained by gradually decreasing the motor control current
―  However, control is inhibited if the power supply voltage is the specified value of less.
U3003:17
Control disabled

Snapshot data
•  The snapshot data stores the currently detected DTC data.

Snapshot data table

—: Not applicable

Snapshot data item

Unit

Data contents

Data read/use method

Corresponding data monitor items
AAT
°C, °F
Ambient air temperature
—
—
APP_STATUS
Accelerator Pedal Off/
Under 20%/
Over 20%/
FAIL
Accelerator pedal position
—
—
CEN_TRQ_S
Nm
Center value of torque sensor
—
CEN_TRQ_S
CFG_STATUS
Config Complete/
Not Configured/
Config Error
Instrument cluster configuration status
—
—
ECT_STATUS
Under 0 degrees C/
0 - Under 80 degrees C/
Over 80 degrees C/
FAIL
Engine coolant temperature status
—
—
ECU_IN_TMP
°C, °F
ECU internal temperature
—
ECU_IN_TMP
ENG_RPM
RPM
Engine speed
—
ENG_RPM
IC_VPWR
V
Instrument cluster power supply
•  The EPS CM constantly receives the power supply voltage value of the instrument cluster sent via CAN signal from the instrument cluster.
•  If a DTC is detected, the EPS CM records the power supply voltage of the instrument cluster when the DTC was detected, and it is displayed in the M-MDS.
VPWR*2
IG-ON_TIMER
hh:mm:ss*1
Elapsed time since ignition was switched ON
Note
•  The instrument cluster records the elapsed time since the ignition was switched ON.
•  The EPS CM constantly receives the elapsed time since the ignition was switched ON sent via CAN signal from the instrument cluster.
•  If a DTC is detected, the EPS CM records the elapsed time since the ignition was switched ON when the DTC was detected, and it is displayed in the M-MDS.
—
LAS_CUR
A
Lane-keep assist system control output current
—
LAS_CUR
MT_CURRENT
A
Motor current
—
MT_CURRENT
OH_CR_C
No/Yes
Current overheat protection control (complete)
—
OH_CR_C
OH_CR_M
No/Yes
Current overheat protection control (middle)
—
OH_CR_M
OH_HIST_C
No/Yes
History of overheat protection control (complete)
—
OH_HIST_C
OH_HIST_M
No/Yes
History of overheat protection control (middle)
—
OH_HIST_M
OH_IG_CNT_C
—
The number of times the ignition is switched ON during the period from when overheat protection control (complete) is finished to the time the next overheat protection control (complete) is started
•  Displays a maximum number of 255 times in which the ignition is switched ON until the first overheat protection control (complete) is started.
•  During overheat protection control (complete), the number of times the ignition is switched ON is not counted, and 0 is displayed.
—
OH_IG_CNT_C
OH_IG_CNT_M
—
The number of times the ignition is switched ON during the period from when overheat protection control (middle) is finished to the time the next overheat protection control (middle) is started
•  Displays a maximum number of 255 times in which the ignition is switched ON until the first overheat protection control (middle) is started.
•  During overheat protection control (middle), the number of times the ignition is switched ON is not counted, and 0 is displayed.
—
OH_IG_CNT_M
PWR_MODE_KEY
Key Out/Key Recently Out (Position 0)/Accessory (Position 1)/Post Ignition (Position 2)/Ignition On (Position 2)/Running (Position 2)/Running - Starting
Power mode key state
•  When a DTC is detected, the EPS CM receives the ignition switch condition being detected by the instrument cluster via CAN signals and displays it in the M-MDS.
—
RPM_STATUS
Engine Stop/
Under 1500rpm/
Over 1500rpm/
FAIL
Engine RPM status
•  The EPS CM constantly receives the ignition switch status sent via CAN signal from the instrument cluster.
•  If a DTC is detected, the EPS CM records the ignition switch status when the DTC was detected, and it is displayed in the M-MDS.
TACHOMTR*2
SHIFT_STATUS
P/N
D/
R/
FAIL
Shift position status
•  The EPS CM constantly receives the selector lever position sent via CAN signal from the instrument cluster.
•  If a DTC is detected, the EPS CM records the selector lever position when the DTC was detected, and it is displayed in the M-MDS.
Not applicable
STR_ANG
°
Steering wheel angle
—
STR_ANG
STR_ANG_EST
°
Steering wheel estimated absolute angle
—
STR_AB_EST
STR_ROT_SPD
°/s
Steering wheel rotation speed
—
STR_ROT_SPD
STR_TRQ_S_M
Nm
Steering shaft torque (Main)
—
STR_TRQ_S_M
STR_TRQ_S_S
Nm
Steering shaft torque (Sub)
—
STR_TRQ_S_S
TOTAL_DIST
km, ft, mi
Accumulated total traveled distance from completion of vehicle until EPS CM detects DTC (Odometer value in instrument cluster)
The distance traveled when the EPS CM detected a DTC can be calculated by performing the following procedure.
1.  Verify the odometer value in the instrument cluster.
2.  Verify the snap shot data item TOTAL_DIST.
3.  Subtract 2 from 1.
—
TOTAL_TIME
hh:mm:ss*1
Accumulated total elapsed time since vehicle completion until EPS CM detects a DTC
Note
•  When the ROOM removed, and the ignition is switched off, the time is not included in the elapsed time.
The elapsed time when the EPS CM detected a DTC can be calculated by performing the following procedure.
1.  Verify the PID item TOTAL_TIME of the instrument cluster.
2.  Verify the snap shot data item TOTAL_TIME.
3.  Subtract 2 from 1.
TOTAL_TIME*2
VPWR
V
Power supply
—
VPWR
VSPD
KPH, MPH
Vehicle speed
—
VSPD
VSPD_STATUS
Stop/
0 - 10 km/h/
Over 10 km/h/
FAIL
Vehicle speed status
•  The EPS CM constantly receives the vehicle speed sent via CAN signal from the instrument cluster.
•  If a DTC is detected, the EPS CM records the vehicle speed when the DTC was detected, and it is displayed in the M-MDS.
SPEEDOMTR*2

*1  :The seconds may be indicated after the decimal point.
*2  :Instrument cluster PID (See ON-BOARD DIAGNOSTIC [INSTRUMENT CLUSTER].)


PID/data monitor function

•  The PID/data monitor function is used for optionally selecting input/output signal monitor items preset in the EPS control module (CM) and reading them out in real-time.

PID/data monitor table

—: Not applicable

PID name (definition)

Unit/Operation

Operation Status (Reference)

Inspection item(s)

EPS control module terminal

M-MDS display
CEN_TRQ_S
Nm
•  Torque sensor neutral position: Near 0 Nm
•  Steering column replacement
—
ECU_IN_TMP
°C, °F
•  Displays temperature of board in EPS control module: -40°C—+215°C {-40°F—419°F}
•  EPS CM replacement
—
LAS_CUR
A
•  Lane-keep assist system is not operated: 0 A
•  Steered: Changes to positive or negative
•  EPS CM replacement
—
ENG_RPM
RPM
•  Engine stopped: 0 RPM
•  Engine rotating at 3,000 rpm: 3,000 RPM
•  PCM inspection
—
MT_CURRENT
A
•  When not steered: Near 0 A
•  Steered: Changes to positive or negative
•  EPS CM replacement
—
OH_CR_C
Yes/No
•  Overheat protection control (complete) is operating: Yes
•  Overheat protection control (complete) is not operating: No
—
—
OH_CR_M
Yes/No
•  Overheat protection control (middle) is operating: Yes
•  Overheat protection control (middle) is not operating: No
—
—
OH_HIST_C
Yes/No
•  Before overheat protection control (complete) has operated: Yes
•  Before overheat protection control (complete) has not operated: No
—
—
OH_HIST_M
Yes/No
•  Before overheat protection control (middle) has operated: Yes
•  Before overheat protection control (middle) has not operated: No
—
—
OH_IG_CNT_C
—
•  The number of times the ignition is switched ON during the period from when overheat protection control (complete) is finished to the time the next overheat protection control (complete) is started
―  Displays a maximum number of 255 times in which the ignition is switched ON until the first overheat protection control (complete) is started.
―  During overheat protection control (complete), the number of times the ignition is switched ON is not counted, and 0 is displayed.
—
—
OH_IG_CNT_M
—
•  The number of times the ignition is switched ON during the period from when overheat protection control (middle) is finished to the time the next overheat protection control (middle) is started
―  Displays a maximum number of 255 times in which the ignition is switched ON until the first overheat protection control (middle) is started.
―  During overheat protection control (middle), the number of times the ignition is switched ON is not counted, and 0 is displayed.
—
—
STR_AB_EST
°
•  Steering wheel in neutral position (not turned): 0°
•  Steered left: Changes to 0°—Positive
•  Steered right: Changes to 0°—Negative
Note
•  The signal displayed in this item is a estimated absolute steering angle signal output.
Perform the DTC inspection for the PCM, DSC HU/CM, and EPS CM.
If a DTC is displayed after performing the DTC inspection for the PCM, DSC HU/CM, and EPS CM, repair the malfunctioning part according to the applicable DTC troubleshooting.
After performing the DTC inspection, perform the following procedures:
•  Switch the ignition off and maintain condition for approx. 3 s.
•  Set the vehicle wheels straight-ahead.
•  Switch the ignition ON (engine off or on).
If an abnormal value is indicated after verifying the value of the STR_ANG again, replace the EPS CM.
—
STR_ANG
°
•  Steering wheel position when ignition is switched ON (engine off or on): 0°
•  Steered left: Changes to 0°—Positive
•  Steered right: Changes to 0°—Negative
Note
•  The signal displayed in this item is a steering angle (relative angle) signal.
—
STR_ROT_SPD
°/s
•  Not steered: Near 0 °/s
•  Steered: Changes according to steering speed
•  EPS CM replacement
—
STR_TRQ_S_M
Nm
•  Not steered: Near 0 Nm
•  Steered left: Changes to 0 Nm—Positive
•  Steered right: Changes to 0 Nm—Negative
•  EPS CM replacement
—
STR_TRQ_S_S
Nm
•  Not steered: Near 0 Nm
•  Steered left: Changes to 0 Nm—Positive
•  Steered right: Changes to 0 Nm—Negative
•  EPS CM replacement
—
VPWR
V
•  Engine stopped: Approx. 12 V
•  Idling: Approx. 14 V
•  Battery inspection
•  Power supply circuit inspection (ignition switch, fuses)
1B
VSPD
KPH, MPH
•  Vehicle stopped: 0 KPH, 0 MPH
•  Vehicle speed 20 km/h {12 mph}: 20 KPH, 12 MPH
•  PCM inspection
—
YAW_RATE
Deg/Sec
•  Vehicle stopped: 0 °/s
•  EPS control module inspection
•  Forward sensing camera inspection
—


External tester communication function

Outline
•  The external tester communication function enables communication of diagnostic data (DTC read-outs, input/output signal read-outs) between the EPS control module (CM) and an external tester.

Connections/Communication Contents

External tester

Mazda modular diagnostic system (M-MDS)

Connection

Communication method
On-board diagnostic (malfunction detection) function
Input/output: CAN_H (HS), CAN_L (HS)
Serial communication
PID/DATA monitor function
Input/output: CAN_H (HS), CAN_L (HS)
Serial communication

Serial communication
•  Serial communication (two-way communication) allows for multiple data to be sent and received instantly along the same line.
•  By connecting the Mazda modular diagnostic system (M-MDS) to the DLC-2, diagnostic data can be sent and received between the Mazda modular diagnostic system (M-MDS) and the EPS CM via CAN lines.
•  The EPS CM receives the command signals of the malfunction detection function and PID/data monitor function from the Mazda modular diagnostic system (M-MDS), and sends DTCs and data regarding the operating status of each input/output part to the Mazda modular diagnostic system (M-MDS).

Diagnostic function name

Signal received

Signal sent
Malfunction detection function
DTC verification signal
Diagnostic trouble code
PID/DATA monitor function
Command signal to read selected monitor item
Monitored data for requested monitor item