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DTC U0298:00 [PCM (SKYACTIV-X)]

id0102u9910500

Outline

System malfunction location

CAN communication: communication error to DC-DC converter (Mazda M Hybrid) (CAN BUS No.2)

Detection condition

•  Communication error between the PCM and DC-DC converter (Mazda M Hybrid) continues for 1 s or more.

Preconditions

•  The ignition switched ON (engine off or on) for 1.5 s.

Fail-safe

•  Inhibits engine-stop by operating the i-stop function.^*1

If U0298:00 is stored before Mazda M Hybrid operates:

•  Power is supplied to the vehicle's electrical devices (12 V power supply) from the battery.

If U0298:00 is stored while or after Mazda M Hybrid operates:

•  Inhibits the motor assist control.

^*1: If U0298:00 is stored during engine stop by i-stop control, restart the engine using the starter.

Possible cause

•  LIN communication line malfunction between DC-DC converter (Mazda M Hybrid) and PCM

•  Main relay or IG1 relay No.2 malfunction

•  DC-DC converter (Mazda M Hybrid) connector or terminals malfunction

•  DC-DC converter (Mazda M Hybrid) power supply circuit malfunction

•  DC-DC converter (Mazda M Hybrid) malfunction (internal malfunction or power supply malfunction)

•  PCM malfunction

System malfunction location	CAN communication: communication error to DC-DC converter (Mazda M Hybrid) (CAN BUS No.2)
Detection condition	• Communication error between the PCM and DC-DC converter (Mazda M Hybrid) continues for 1 s or more. Preconditions • The ignition switched ON (engine off or on) for 1.5 s.
Fail-safe	• Inhibits engine-stop by operating the i-stop function.^1 If U0298:00 is stored before Mazda M Hybrid operates: • Power is supplied to the vehicle's electrical devices (12 V power supply) from the battery. If U0298:00 is stored while or after Mazda M Hybrid operates: • Inhibits the motor assist control. ^1: If U0298:00 is stored during engine stop by i-stop control, restart the engine using the starter.
Possible cause	• LIN communication line malfunction between DC-DC converter (Mazda M Hybrid) and PCM • Main relay or IG1 relay No.2 malfunction • DC-DC converter (Mazda M Hybrid) connector or terminals malfunction • DC-DC converter (Mazda M Hybrid) power supply circuit malfunction • DC-DC converter (Mazda M Hybrid) malfunction (internal malfunction or power supply malfunction) • PCM malfunction

Diagnostic Procedure

Step

Inspection

Results

Action

1

RECORD VEHICLE STATUS WHEN DTC WAS DETECTED TO UTILIZE WITH REPEATABILITY VERIFICATION

•  Record the freeze frame data/snapshot data.

Note

•  Recording can be facilitated using the screen capture function of the PC.

—

Go to the next step.

2

VERIFY RELATED REPAIR INFORMATION OR SERVICE INFORMATION AVAILABILITY

•  Verify related Service Bulletins, on-line repair information, or Service Information availability.

•  Is any related Information available?

Yes

Perform repair or diagnosis according to the available information.

•  If the vehicle is not repaired, go to the next step.

No

Go to the next step.

3

INSPECT FOR OTHER RELATED DTCs

•  Perform the DTC inspection for the PCM.
(See DTC INSPECTION.)

•  Are any other DTCs displayed?

Yes

Repair the malfunctioning location according to the applicable DTC troubleshooting.

(See DTC TABLE [PCM (SKYACTIV-X)].)

No

Go to the next step.

4

INSPECT SUB RELAY AND IG1 RELAY No.2 FOR MALFUNCTION

•  Inspect the applicable part.
(See RELAY INSPECTION.)

•  Is the part normal?

Yes

Install the relay, then go to the next step.

(See RELAY LOCATION [(E)].)

No

Repair or replace the malfunctioning location and perform the repair completion verification.

(See RELAY LOCATION [(E)].)

5

INSPECT DC-DC CONVERTER (Mazda M Hybrid) CONNECTOR FOR MALFUNCTION

•  Inspect the applicable connector and terminal.
(See CONNECTOR INSPECTION.)

•  Are the connector and terminal normal?

Yes

Go to the next step.

No

Repair or replace the malfunctioning location and perform the repair completion verification.

6

INSPECT DC-DC CONVERTER (Mazda M Hybrid) POWER SUPPLY CIRCUIT FOR SHORT TO GROUND AND OPEN CIRCUIT

•  Inspect the power supply circuit for an open circuit and short to ground.
(See CIRCUIT INSPECTION.)

•  Is the circuit normal?

Yes

Go to the next step.

No

Repair or replace the malfunctioning location and perform the repair completion verification.

7

INSPECT DC-DC CONVERTER (Mazda M Hybrid) FOR MALFUNCTION

•  Inspect the applicable part.
(See DC-DC CONVERTER (Mazda M Hybrid) INSPECTION.)

•  Is the part normal?

Yes

Go to the next step.

No

Repair or replace the malfunctioning location and perform the repair completion verification.

(See DC-DC CONVERTER (Mazda M Hybrid) REMOVAL/INSTALLATION.)

Repair completion verification 1

VERIFY THAT VEHICLE IS REPAIRED

•  Install/connect the part removed/disconnected during the troubleshooting procedure.

•  Clear the DTC recorded in the memory.
(See CLEARING DTC.)

•  Replicate the vehicle conditions at the time the DTC was detected using the following procedure.

―  Perform the KOEO or KOER self test.
(See DTC INSPECTION.)

•  Perform the DTC inspection for the PCM.
(See DTC INSPECTION.)

•  Is the same Pending DTC present?

Yes

Refer to the controller area network (CAN) malfunction diagnosis flow to inspect for a CAN communication error.

(See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW [(E)].)

If the CAN communication is normal, perform the diagnosis from Step 1.

•  If the malfunction recurs, replace the PCM, then go to the next step.
(See PCM REMOVAL/INSTALLATION [SKYACTIV-X 2.0].)

No

Go to the next step.

Repair completion verification 2

VERIFY IF OTHER DTCs DISPLAYED

•  Perform the DTC inspection.
(See DTC INSPECTION.)

•  Are any other DTCs displayed?

Yes

Repair the malfunctioning location according to the applicable DTC troubleshooting.

No

DTC troubleshooting completed.

Step	Inspection	Results	Action
1	RECORD VEHICLE STATUS WHEN DTC WAS DETECTED TO UTILIZE WITH REPEATABILITY VERIFICATION • Record the freeze frame data/snapshot data. Note • Recording can be facilitated using the screen capture function of the PC.	—	Go to the next step.
2	VERIFY RELATED REPAIR INFORMATION OR SERVICE INFORMATION AVAILABILITY • Verify related Service Bulletins, on-line repair information, or Service Information availability. • Is any related Information available?	Yes	Perform repair or diagnosis according to the available information. • If the vehicle is not repaired, go to the next step.
2		No	Go to the next step.
3	INSPECT FOR OTHER RELATED DTCs • Perform the DTC inspection for the PCM. (See DTC INSPECTION.) • Are any other DTCs displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting. (See DTC TABLE [PCM (SKYACTIV-X)].)
3		No	Go to the next step.
4	INSPECT SUB RELAY AND IG1 RELAY No.2 FOR MALFUNCTION • Inspect the applicable part. (See RELAY INSPECTION.) • Is the part normal?	Yes	Install the relay, then go to the next step. (See RELAY LOCATION [(E)].)
4		No	Repair or replace the malfunctioning location and perform the repair completion verification. (See RELAY LOCATION [(E)].)
5	INSPECT DC-DC CONVERTER (Mazda M Hybrid) CONNECTOR FOR MALFUNCTION • Inspect the applicable connector and terminal. (See CONNECTOR INSPECTION.) • Are the connector and terminal normal?	Yes	Go to the next step.
5		No	Repair or replace the malfunctioning location and perform the repair completion verification.
6	INSPECT DC-DC CONVERTER (Mazda M Hybrid) POWER SUPPLY CIRCUIT FOR SHORT TO GROUND AND OPEN CIRCUIT • Inspect the power supply circuit for an open circuit and short to ground. (See CIRCUIT INSPECTION.) • Is the circuit normal?	Yes	Go to the next step.
6		No	Repair or replace the malfunctioning location and perform the repair completion verification.
7	INSPECT DC-DC CONVERTER (Mazda M Hybrid) FOR MALFUNCTION • Inspect the applicable part. (See DC-DC CONVERTER (Mazda M Hybrid) INSPECTION.) • Is the part normal?	Yes	Go to the next step.
7		No	Repair or replace the malfunctioning location and perform the repair completion verification. (See DC-DC CONVERTER (Mazda M Hybrid) REMOVAL/INSTALLATION.)
Repair completion verification 1	VERIFY THAT VEHICLE IS REPAIRED • Install/connect the part removed/disconnected during the troubleshooting procedure. • Clear the DTC recorded in the memory. (See CLEARING DTC.) • Replicate the vehicle conditions at the time the DTC was detected using the following procedure. ― Perform the KOEO or KOER self test. (See DTC INSPECTION.) • Perform the DTC inspection for the PCM. (See DTC INSPECTION.) • Is the same Pending DTC present?	Yes	Refer to the controller area network (CAN) malfunction diagnosis flow to inspect for a CAN communication error. (See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW [(E)].) If the CAN communication is normal, perform the diagnosis from Step 1. • If the malfunction recurs, replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION [SKYACTIV-X 2.0].)
Repair completion verification 1		No	Go to the next step.
Repair completion verification 2	VERIFY IF OTHER DTCs DISPLAYED • Perform the DTC inspection. (See DTC INSPECTION.) • Are any other DTCs displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting.
Repair completion verification 2		No	DTC troubleshooting completed.