Mazda CX 7. Manual - part 44

ON-BOARD DIAGNOSTIC [L3 WITH TC]

01-02–131

01-02

End Of Sie

WM: DTC P04XX

DTC P0401[L3 WITH TC]

id010239815300

13

INSPECT STOPPER PIN MECHANISM

• Remove the timing chain.

• Inspect the stopper pin.

 (See01-10-27 VARIABLE VALVE TIMING 
ACTUATOR INSPECTION[L3 WITH TC].)

• Is the stopper pin mechanism normal?

Yes

Go to the next step.

No

Replace the variable valve timing actuator, then go to Step 
15.

14

INSPECT ROTOR POSITION

• Remove the variable valve timing actuator.

(See01-10-28 VARIABLE VALVE TIMING 
ACTUATOR REMOVAL/INSTALLATION[L3 
WITH TC])

• Is the rotor position at the maximum valve 

timing retard?

Yes

VARIABLE VALVE TIMING MECHANISM NORMAL

Note

• This DTC is detected as an intermittent concern.

• The intermittent concern might be removed by 

cleaning the variable valve timing mode control 
function.

Go to the next step.

No

Replace the variable valve timing actuator, then go to the 
next step.

15

VERIFY TROUBLESHOOTING OF DTC P0340 
COMPLETED

• Make sure to reconnect all disconnected 

connectors.

• Turn ignition switch to the ON position (Engine 

off).

• Clear the DTC from the PCM memory using 

the M-MDS.

• Start the engine.

• Access the MAF PID using the M-MDS.

Note

• The MAF PID should indicate 1.95 g/s 

{0.25 lb/min.} or above during this test

• Is same DTC present?

Yes

Replace the PCM, then go to the next step.
 (See01-40-6 PCM REMOVAL/INSTALLATION[L3 WITH 
TC].)

No

Go to the next step.

16

VERIFY AFTER REPAIR PROCEDURE

• Perform the “After Repair Procedure”.

 (See01-02-10 AFTER REPAIR 
PROCEDURE[L3 WITH TC].)

• Are any DTCs present?

Yes

Go to the applicable DTC inspection.
 (See01-02-13 DTC TABLE[L3 WITH TC].)

No

Troubleshooting completed.

STEP

INSPECTION

ACTION

DTC P0401

EGR flow insufficient detected

DETECTION 

CONDITION

• PCM monitors the difference in intake manifold pressures when the EGR is operated and when it is 

stopped. If the difference is too small, the PCM determines that the EGR flow is insufficient.

Diagnostic support note

• This is an intermittent monitor (EGR system).

• The MIL illuminates if the PCM detects the above malfunction condition in two consecutive drive cycles or 

in one drive cycle while the DTC for the same malfunction has been stored in the PCM.

• PENDING CODE is available if the PCM detects the above malfunction condition during first drive cycle.

• FREEZE FRAME DATA is available.

• DTCs are stored in the PCM memory.

POSSIBLE 

CAUSE

• EGR valve malfunction

• MAP sensor malfunction

• EGR gasket malfunction

• Vacuum hose looseness or damage

• PCM malfunction

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ON-BOARD DIAGNOSTIC [L3 WITH TC]

01-02–132

Diagnostic procedure

STEP

INSPECTION

ACTION

1

VERIFY FREEZE FRAME DATA AND 
DIAGNOSTIC MONITORING TEST RESULTS 
HAVE BEEN RECORDED

• Have the FREEZE FRAME DATA and 

DIAGNOSTIC MONITORING TEST RESULTS 
(EGR system related) been recorded?

Yes

Go to the next step.

No

Record FREEZE FRAME DATA and DIAGNOSTIC 
MONITORING TEST RESULTS on the repair order, then 
go to the next step.

2

VERIFY RELATED REPAIR INFORMATION 
AVAILABILITY

• Check for related Service Bulletins and/or on-

line repair information availability.

• Is any related repair information available?

Yes

Perform the repair or diagnosis according to the available 
repair information.

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

No

Go to the next step.

3

INSPECT FOR OTHER DTCS

• Turn the ignition switch off then to the ON 

position (Engine off).

• Have other DTCs been stored?

Yes

Repair the circuit malfunction for applicable DTCs.

No

Go to the next step.

4

INSPECT VACUUM HOSE CONDITION

• Inspect freezing vacuum hoses for clogs, 

damage, frozen, or vacuum leakage.

• Is there any malfunction?

Yes

Replace the vacuum hoses, then go to Step 8.

No

Go to the next step.

5

INSPECT EGR VALVE MALFUNCTION

• Inspect the EGR valve.

(See01-16-12 EGR VALVE INSPECTION[L3 
WITH TC].)

• Is the EGR valve normal?

Yes

Go to the next step.

No

Replace the EGR valve, then go to Step 8.

6

INSPECT MAP SENSOR MALFUNCTION

• Perform the MAP sensor inspection.

(See01-40-29 MANIFOLD ABSOLUTE 
PRESSURE (MAP) SENSOR 
INSPECTION[L3 WITH TC].)

• Is the EGR valve normal?

Yes

Go to the next step.

No

Replace the MAP sensor, then go to Step 8.

7

INSPECT EGR VALVE PASSAGE

• Turn the ignition switch off.

• Remove the EGR valve.

• Is the gasket installation normal?

Yes

Go to the next step.

No

Install the gasket correctly, then go to the next step.

8

MONITOR EGR SYSTEM BY DRIVE MODE

• Clear the DTC from the PCM memory using 

the M-MDS.

• Run the PCM Adaptive Memory Procedure 

Drive Mode.
(See01-02-10 OBD-II DRIVE MODE[L3 WITH 
TC].)

• Stop the vehicle and access the ON BOARD 

READINESS TEST to inspect the DRIVE 
MODE completion status.

• Verify the FUEL_EVAL and EGR_EVAL PIDs 

status.

• Do the FUEL_EVAL and EGR_EVAL PIDs 

change to Yes?

Yes

Go to the next step.

No

Retry this step.

9

VERIFY TROUBLESHOOTING OF DTC P0401 
COMPLETED

• Make sure to reconnect all disconnected 

connectors.

• Access the DIAGNOSTIC MONITORING 

TEST RESULTS.
(See01-02-7 ON-BOARD DIAGNOSTIC 
TEST[L3 WITH TC].)

• Verify the TEST #10: 31: 83 (EGR pressure 

variation) value.

• Is the value within the specification?

Yes

Go to the next step.

No

Replace the PCM, then go to the next step.

10

VERIFY AFTER REPAIR PROCEDURE

• Perform the “AFTER REPAIR PROCEDURE”.

(See01-02-10 AFTER REPAIR 
PROCEDURE[L3 WITH TC].)

• Are any DTCs present?

Yes

Go to the applicable DTC inspection.
(See01-02-13 DTC TABLE[L3 WITH TC].)

No

Troubleshooting completed.

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ON-BOARD DIAGNOSTIC [L3 WITH TC]

01-02–133

01-02

End Of Sie

DTC P0403[L3 WITH TC]

id010239807100

DTC P0403

EGR valve (stepper motor) circuit malfunction

DETECTION 

CONDITION

• PCM monitors the input voltage from the EGR valve. If the voltage remain low or high, the PCM determines 

that the EGR valve circuit has a malfunction.

Diagnostic support note

• This is a continuous monitor (CCM).

• MIL illuminates if the PCM detects above malfunction condition in two consecutive drive cycles or in one 

drive cycle while the DTC for the same malfunction has been stored in the PCM.

• PENDING CODE is available if the PCM detects the above malfunction condition during first drive cycle.

• FREEZE FRAME DATA is not available.

• DTCs are not stored in the PCM memory.

POSSIBLE 

CAUSE

• EGR valve malfunction

• Connector or terminal malfunction

• Short to the power supply in the wiring harness between EGR valve terminal E and PCM terminal 2AQ

• Short to the power supply in the wiring harness between EGR valve terminal A and PCM terminal 2AM

• Short to the power supply in the wiring harness between EGR valve terminal B and PCM terminal 2AR

• Short to the power supply in the wiring harness between EGR valve terminal F and PCM terminal 2AN

• Short to ground circuit in wiring harness between EGR valve terminal E and PCM terminal 2AQ

• Short to ground circuit in wiring harness between EGR valve terminal A and PCM terminal 2AM

• Short to ground circuit in wiring harness between EGR valve terminal B and PCM terminal 2AR

• Short to ground circuit in wiring harness between EGR valve terminal F and PCM terminal 2AN

• Open circuit in the wiring harness between EGR valve terminal E and PCM terminal 2AQ

• Open circuit in the wiring harness between EGR valve terminal A and PCM terminal 2AM

• Open circuit in the wiring harness between EGR valve terminal B and PCM terminal 2AR

• Open circuit in the wiring harness between EGR valve terminal F and PCM terminal 2AN

• Open circuit in the wiring harness between main relay terminal D and EGR valve terminal C

• Open circuit in the wiring harness between main relay terminal D and EGR valve terminal D

• PCM malfunction

MAIN RELAY

C

E

A

B

F

D

C

2AQ

2AM

2AR

2AN

PCM

PCM

WIRING HARNESS SIDE CONNECTOR

EGR VALVE

WIRING HARNESS SIDE CONNECTOR

C

D

A

B

E

F

EGR VALVE

5

7

8

6

4

3

3

3

3

3

3

9

7

8

6

9

7

8

6

9

7

8

6

9

2BE 2BA 2AW 2AS 2AO 2AK 2AG 2AC 2Y 2U 2Q 2M

2E

2A

2I

2BH 2BD 2AZ 2AV 2AR 2AN 2AJ 2AF 2AB 2X 2T 2P

2H

2D

2L

2BG 2BC 2AY 2AU 2AQ 2AM 2AI 2AE 2AA 2W 2S 2O

2G

2C

2K

2BF 2BB 2AX 2AT 2AP 2AL 2AH 2AD 2Z

2V 2R 2N

2F

2B

2J

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ON-BOARD DIAGNOSTIC [L3 WITH TC]

01-02–134

Diagnostic procedure

STEP

INSPECTION

ACTION

1

VERIFY FREEZE FRAME DATA HAS BEEN 
RECORDED

• Has the FREEZE FRAME DATA been 

recorded?

Yes

Go to the next step.

No

Record FREEZE FRAME DATA on the repair order, then go 
to the next step.

2

VERIFY RELATED REPAIR INFORMATION 
AVAILABILITY

• Check for related Service Bulletins and/or on-

line repair information availability.

• Is any related repair information available?

Yes

Perform the repair or diagnosis according to the available 
repair information.

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

No

Go to the next step.

3

INSPECT EGR VALVE CONNECTOR FOR POOR 
CONNECTION

• Turn the ignition switch off.

• Disconnect the EGR valve connector.

• Inspect for poor connection (such as damaged/

pulled-out pins, corrosion).

• Is there any malfunction?

Yes

Repair or replace the terminals and/or connector, then go 
to Step 10.

No

Go to the next step.

4

INSPECT POWER CIRCUIT FOR OPEN CIRCUIT

•  Turn ignition switch to the ON position (Engine 

off).

•  Measure the voltage following the terminal and 

body ground.
— EGR valve terminal C (harness-side)

— EGR valve terminal D (harness-side)

•  Is voltage B+?

Yes

Go to the next step.

No

Repair or replace the wiring harness for an open circuit 
then go to Step 10.

5

INSPECT EGR VALVE

• Perform the EGR valve inspection.

(See01-16-12 EGR VALVE INSPECTION[L3 
WITH TC].)

•  Is the EGR valve normal?

Yes

Go to the next step.

No

Replace the EGR valve, then go to Step 10.

6

INSPECT FOR CONTROL CIRCUIT FOR SHORT 
TO GROUND

• Turn the ignition switch off.

• Inspect for continuity between the following 

terminals and body ground:
— EGR valve terminal E (harness-side)

— EGR valve terminal A (harness-side)

— EGR valve terminal B (harness-side)

— EGR valve terminal F (harness-side)

• is there continuity?

Yes

Repair or replace the wiring harness for a short to ground, 
then go to Step 10.

No

Go to the next step.

7

INSPECT FOR CONTROL CIRCUIT FOR SHORT 
TO POWER SUPPLY

• Turn the ignition switch to the ON position 

(Engine off).

• Measure the voltage between the following 

terminals and body ground:
— EGR valve terminal E (harness-side)

— EGR valve terminal A (harness-side)

— EGR valve terminal B (harness-side)

— EGR valve terminal F (harness-side)

• Is voltage B+?

Yes

Repair or replace wiring harness for a short to power 
supply, then go to Step 10.

No

Go to the next step.

8

INSPECT PCM CONNECTOR FOR POOR 
CONNECTION

• Turn the ignition switch off.

• Disconnect PCM connector.

• Inspect for poor connection (such as damaged/

pulled-out pins, corrosion).

• Is there any malfunction?

Yes

Repair or replace the terminals and/or connector, then go 
to Step 10.

No

Go to the next step.

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