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Free to use workshop manual for your 2015+ Mk4 'ND' Mazda MX-5
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ON-BOARD DIAGNOSTIC SYSTEM [EPS CONTROL MODULE]

Outline

  • The on-board diagnostic system consists of the following functions:

    • A malfunction detection function that detects abnormalities in input/output signals when the ignition switch is at the ON position.

    • A PID/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) has following functions:

    • PID/data monitor access

    • DTC clear using the display screen of the diagnostic tester

Block diagram

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 alert 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 function and fail-safe function.

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
×: Applicable—: Not applicable

DTC

Power steering malfunction indicator light

Description

Fail-safe

Drive cycle

Self test type*1

Memory function

C200B:02

Illuminated

Torque sensor

×

—

C, D

×

C200B:1C

Illuminated

Torque sensor

×

—

C, D

×

C200B:62

Illuminated

Torque sensor

×

—

C, D

×

C200C:1C

Illuminated

Torque sensor

×

—

C, D

×

C200D:1C

Illuminated

Resolver sensor

×

—

C, D

×

C200D:64

Illuminated

Resolver sensor

×

—

C, D

×

U0001:88

Illuminated

CAN communication: module communication error

×

—

C, D

×

U0100:00

Illuminated

CAN communication: communication error to PCM

×

—

C, D

×

U0121:00

Not illuminated

CAN communication: communication error to DSC HU/CM

×

—

C, D

×

U0155:00

Not illuminated

CAN communication: communication error to instrument cluster

×

—

C, D

×

U0338:00

Not illuminated

Signal error from start stop unit

×

—

C, D

×

U0401:00

Illuminated

Signal error from PCM (engine speed signal error before assist started)

×

—

C, D

×

Not illuminated

Signal error from PCM (engine speed signal error after assist started)

×

—

C, D

×

Illuminated

Signal error from PCM (vehicle speed signal error)

×

—

C, D

×

U0415:00

Not illuminated

Signal error from DSC HU/CM

×

—

C, D

×

U0423:00

Not illuminated

Signal error from instrument cluster

×

—

C, D

×

U0515:00

Not illuminated

Signal error from start stop unit

×

—

C, D

×

U2011:19

Illuminated

EPS motor

×

—

C, D

×

U2011:1C

Illuminated

EPS motor

×

—

C, D

×

U2011:61

Illuminated

EPS motor

×

—

C, D

×

U2011:62

Illuminated

EPS motor

×

—

C, D

×

U2011:64

Illuminated

EPS motor

×

—

C, D

×

U2011:72

Illuminated

EPS motor

×

—

C, D

×

U2011:92

Illuminated

EPS motor

×

—

C, D

×

U2300:54

Not illuminated

Configuration

×

—

C, D

×

U2300:55

Illuminated

Configuration

×

—

C, D

×

U2300:56

Not illuminated

Configuration

×

—

C, D

×

U3000:16

Illuminated

EPS control module

×

—

C, D

×

U3000:1C

Illuminated

EPS control module

×

—

C, D

×

U3000:28

Illuminated

EPS control module

×

—

C, D

×

U3000:41

Illuminated

EPS control module

×

—

C, D

×

U3000:46

Not illuminated

EPS control module

×

—

C, D

×

U3000:47

Illuminated

EPS control module

×

—

C, D

×

U3000:49

Illuminated

EPS control module

×

—

C, D

×

U3000:4B

Not illuminated

EPS control module

×

—

C, D

×

U3000:61

Illuminated

EPS control module

×

—

C, D

×

U3000:64

Illuminated

EPS control module

×

—

C, D

×

U3000:73

Illuminated

EPS control module

×

—

C, D

×

U3000:96

Illuminated

EPS control module

×

—

C, D

×

U3003:16

Illuminated

Power supply

×

—

C, D

×

U3003:17

Illuminated

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 seven-digit DTC.

  • 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.

Fail-safe function

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

Fail-safe function table

DTC

EPS motor current control

C200B:02

Permits control

C200B:1C

Permits control

C200B:62

Permits control

C200C:1C

Permits control

C200D:1C

Inhibits control

C200D:64

Inhibits control

U0001:88

Permits control

U0100:00

Control is permited by gradually decreasing the motor current

U0121:00

Permits control

U0155:00

Permits control

U0338:00

Permits control

U0401:00

  • Engine speed (before assist started)

    • Inhibits control

  • Engine speed (after assist started)

    • Permits control

  • Vehicle speed

    • Control is permited by gradually decreasing the motor current

U0415:00

Permits control

U0423:00

Permits control

U0515:00

Permits control

U2011:19

Inhibits control

U2011:1C

Inhibits control

U2011:61

Inhibits control

U2011:62

Inhibits control

U2011:64

Inhibits control

U2011:72

Inhibits control

U2011:92

Inhibits control

U2300:54

Permits control

U2300:55

Permits control

U2300:56

Permits control

U3000:16

Inhibits control

U3000:1C

Inhibits control

U3000:28

Inhibits control

U3000:41

Inhibits control

U3000:46

Permits control

U3000:47

Inhibits control

U3000:49

Inhibits control

U3000:4B

Permits control

U3000:61

Inhibits control

U3000:64

Permits control

U3000:73

Inhibits control

U3000:96

Inhibits control

U3003:16

Inhibits control

U3003:17

Inhibits control
Snapshot data

  • The snapshot data stores the currently detected DTC data.

—: Not applicable

Snapshot data item

Unit

Definition

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

—

—

CFG_STATUS

Config Complete/

Not Configured/

Config Error

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 control module 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 control module records the power supply voltage of the instrument cluster when the DTC was detected, and it is displayed in the M-MDS.

—

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 control module 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 control module records the elapsed time since the ignition was switched ON when the DTC was detected, and it is displayed in the M-MDS.

—

MT_CURRENT

A

EPS motor control 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/Key Approved (Position 0)/Post Accessory (Position 0)/Accessory (Position 1)/Post Ignition (Position 1)/Ignition On (Position 2)/Running (Position 2)/Running - Starting In Progress (Position 2)/Crank (Position 3)

  • Key Out: Ignition switched off

  • Key Recently Out (Position 0): Elapsed time within 3 s since ignition was switched off

  • Accessory (Position 1): Ignition is switched to ACC

  • Post Ignition (Position 2): Elapsed time within 3 s since ignition was switched ON

  • Ignition On (Position 2): Ignition switched ON (engine off)

  • Running (Position 2): Ignition switched ON (engine on)

  • Running - Starting: Cranking condition

  • The EPS control module constantly receives the ignition switch status sent via CAN signal from the instrument cluster.

  • If a DTC is detected, the EPS control module records the ignition switch status when the DTC was detected, and it is displayed in the M-MDS.

—

RPM_STATUS

Engine Stop/

Under 1500 rpm/

Over 1500 rpm/

FAIL

Engine RPM status

  • The EPS control module constantly receives the ignition switch status sent via CAN signal from the instrument cluster.

  • If a DTC is detected, the EPS control module records the ignition switch status when the DTC was detected, and it is displayed in the M-MDS.

—

SHIFT_STATUS

P/N

D/

R/

FAIL

Shift position status

  • The EPS control module constantly receives the selector lever position sent via CAN signal from the instrument cluster.

  • If a DTC is detected, the EPS control module records the selector lever position when the DTC was detected, and it is displayed in the M-MDS.

—

STR_ANG

°

Steering wheel angle

—

STR_ANG

STR_ANG_EST

°

Steering wheel angle (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 control module detects DTC (Odometer value in instrument cluster)

The distance traveled when the EPS control module 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 control module detects a DTC

NOTE:

  • When the ROOM fuse is removed, and the ignition is switched off, the time is not included in the elapsed time.

The elapsed time when the EPS control module 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.

—

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 control module constantly receives the vehicle speed sent via CAN signal from the instrument cluster.

  • If a DTC is detected, the EPS control module records the vehicle speed when the DTC was detected, and it is displayed in the M-MDS.

—
*1
Fractions of seconds may be indicated after the decimal point
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 and reading them out in real-time.

Monitor item

Unit/operation

Definition

ECU_IN_TMP

°C, °F

ECU internal temperature

ENG_RPM

RPM

Engine speed

MT_CURRENT

A

Motor control current

OH_CR_C

Yes/No

Current overheat protection control (complete)

OH_CR_M

Yes/No

Current overheat protection control (middle)

OH_HIST_C

Yes/No

History of overheat protection control (complete)

OH_HIST_M

Yes/No

History of overheat protection control (middle)

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 angle (estimated absolute angle)

STR_ANG

°

Steering wheel angle (relative angle)

STR_ROT_SPD

°/s

Steering wheel rotation speed

STR_TRQ_S_M

Nm

Steering shaft torque (main)

STR_TRQ_S_S

Nm

Steering shaft torque (sub)

VPWR

V

Power supply

VSPD

KPH, MPH

Vehicle speed
External tester communication function

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

  • 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 control module via CAN lines.

  • The EPS control module 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

DTC(s)

PID/data monitor function

Command signal to read selected monitor item

Monitored data for requested monitor item
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Free to use workshop manual for your 2015+ Mk4 'ND' Mazda MX-5

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