Mazda CX-9 Grand Touring. Manual — part 226

DIAGNOSTIC PROCEDURE

DTC P0020 (MZI-3.7) DIAGNOSTIC PROCEDURE

STEP

INSPECTION

ACTION

1

VERIFY FREEZE FRAME DATA HAS
BEEN RECORDED



Has 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



Verify related Service Bulletins and/or
on-line repair information availability.



Is any related Service Bulletins

Yes

Perform repair or diagnosis according to the
available Service Bulletins.



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

2008 Mazda CX-9 Grand Touring

2008 ENGINE PERFORMANCE On-Board Diagnostic (MZI-3.7) - Mazda CX-9

Microsoft

Sunday, November 15, 2009 10:08:34 AM

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© 2005 Mitchell Repair Information Company, LLC.

available?

No

Go to the next step.

3

INSPECT OCV (LH) CONNECTOR
FOR POOR CONNECTION



Turn the ignition switch off.



Disconnect the OCV (LH) connector.



Inspect for poor connection (such as
damaged/pulled-out pins, corrosion).



Are there any malfunction?

Yes

Repair or replace suspected part, then go to Step
10.

No

Go to the next step.

4

INSPECT OCV (LH)



Inspect the OCV (LH).

(See OIL CONTROL VALVE
(OCV) INSPECTION [MZI-3.7] .)



Is there any malfunction?

Yes

Replace the OCV (LH), then go to Step 10. (See
OIL CONTROL VALVE (OCV)
REMOVAL/INSTALLATION [MZI-3.7] .)

No

Go to the next step.

5

INSPECT OCV (LH) CIRCUIT FOR
OPEN CIRCUIT



Turn the ignition switch to the ON
position (Engine off).



Measure the voltage between the OCV
(LH) connector terminal A (wiring
harness-side) and body ground.



Is the voltage B+?

Yes Go to the next step.

No

Repair or replace suspected part, then go to Step

10.

6

INSPECT OCV (LH) CIRCUIT FOR
SHORT TO POWER SUPPLY



Disconnect the PCM connector.



Turn the ignition switch to the ON
position (Engine off).



Measure the voltage between the OCV
(LH) connector terminal B and body
ground.



Is the voltage B+?

Yes

Repair or replace suspected part, then go to Step
10.

No

Go to the next step.

7

INSPECT OCV (LH) CIRCUIT FOR
SHORT TO GROUND



Turn the ignition switch to the ON
position (Engine off).



Inspect for continuity between OCV
(LH) terminal B (wiring harness-side)
and body ground.

Yes

Repair or replace suspected part, then go to Step
10.

2008 Mazda CX-9 Grand Touring

2008 ENGINE PERFORMANCE On-Board Diagnostic (MZI-3.7) - Mazda CX-9

Microsoft

Sunday, November 15, 2009 10:08:34 AM

Page 38

© 2005 Mitchell Repair Information Company, LLC.

DTC P0021 [MZI-3.7]



Is there continuity?

No

Go to the next step.

8

INSPECT PCM CONNECTOR FOR
POOR CONNECTION



Disconnect the PCM connector.



Inspect for poor connection (such as
damaged/pulled-out pins, corrosion).



Is there any malfunction?

Yes

Repair or replace suspected part, then go to Step
10.

No

Go to the next step.

9

INSPECT OCV (LH) CIRCUIT FOR
OPEN CIRCUIT



Turn the ignition switch off.



Measure the resistance between the
OCV (LH) connector terminal B
(wiring harness-side) and PCM
terminal 2BK (wiring harness-side).



Is there continuity?

Yes Go to the next step.

No

Repair or replace suspected part, Then go to the

next step.

10

VERIFY TROUBLESHOOTING OF
DTC P0020 HAS BEEN COMPLETED



Verify that all disconnected
connectors reconnected.



Turn the ignition switch to the ON
position (Engine off).



Clear the DTC from the PCM memory
using the M-MDS.



Start the engine and run it at idle.



Retrieve DTCs using the M-MDS.



Is the PENDING CODE for this DTC
present?

Yes

Replace the PCM, then go to the next step. (See
PCM REMOVAL/INSTALLATION [MZI-
3.7] .)

No

Go to the next step.

11

VERIFY AFTER REPAIR
PROCEDURE



Perform the "AFTER REPAIR
PROCEDURE".

(See AFTER REPAIR
PROCEDURE [MZI-3.7].)



Are any DTC present?

Yes

Go to the applicable DTC inspection. (See DTC
TABLE [MZI-3.7].)

No

Troubleshooting completed.

2008 Mazda CX-9 Grand Touring

2008 ENGINE PERFORMANCE On-Board Diagnostic (MZI-3.7) - Mazda CX-9

Microsoft

Sunday, November 15, 2009 10:08:34 AM

Page 39

© 2005 Mitchell Repair Information Company, LLC.

DTC P0021 (MZI-3.7) DETECTION CONDITIONS AND POSSIBLE CAUSES

DIAGNOSTIC PROCEDURE

DTC P0021 (MZI-3.7) DIAGNOSTIC PROCEDURE

DTC P0021

CMP timing over-advanced (LH)

DETECTION

CONDITION



The PCM monitors the variable valve timing position for an over-advanced
camshaft timing. The test fails when the camshaft timing exceeds a maximum
calibrated value or remains in an advanced position.

POSSIBLE

CAUSE



OCV (LH) malfunction



Spool valve in OCV (LH) is stuck in advanced position



Improper valve timing due to timing chain slippage

STEP

INSPECTION

ACTION

1

VERIFY FREEZE FRAME DATA HAS
BEEN RECORDED



Has 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



Verify related Service Bulletins and/or
on-line repair information availability.



Is any related Service Bulletins
available?

Yes

Perform repair or diagnosis according to the
available Service Bulletins.



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

No

Go to the next step.

3

VERIFY TIMING CHAIN
INSTALLATION



Stop the engine.



Remove the front cover.



Is the camshaft timing mark at the
correct point?

(See TIMING CHAIN
REMOVAL/INSTALLATION
[MZI-3.7] .)

Yes Go to the next step.

No

Reinstall the timing chain, then go to Step 5.

4

INSPECT OCV (LH)



Inspect the OCV (LH).

(See OIL CONTROL VALVE
(OCV) INSPECTION [MZI-3.7] .)



Is there any malfunction?

Yes

Replace the OCV (LH), then go to the next step.
(See OIL CONTROL VALVE (OCV)
REMOVAL/INSTALLATION [MZI-3.7] .)

No

Go to the next step.

2008 Mazda CX-9 Grand Touring

2008 ENGINE PERFORMANCE On-Board Diagnostic (MZI-3.7) - Mazda CX-9

Microsoft

Sunday, November 15, 2009 10:08:34 AM

Page 40

© 2005 Mitchell Repair Information Company, LLC.