Mazda CX-9 Grand Touring. Manual — part 278

DTC P050E [MZI-3.7]

DTC P050E (MZI-3.7) DETECTION CONDITIONS AND POSSIBLE CAUSES

4



Remove air cleaner element with the
engine running.



Is the engine speed increased?

Yes 7.

No

Go to the next step.

5

INSPECT INTAKE AIR SYSTEM FOR
EXCESSIVE AIR SUCTION



Visually inspect the hose in intake air
system for looseness or damages.



Is there any malfunction?

Yes

Repair or replace the malfunctioning part, then
go to Step 7.

No

Go to the next step.

6

INSPECT THROTTLE BODY
PASSAGE



Is the throttle body clogged?

Yes

Clean or replace the throttle body passage, then
go to Step 7.

No

Go to the next step.

7

VERIFY TROUBLESHOOTING OF
DTC P0507 HAS BEEN COMPLETED



Verify that all disconnected
connectors reconnected.



Start the engine.



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



Depress brake pedal for 14 s or more.



Is 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.

8

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.

DTC P050E

Cold start engine exhaust temperature out of range

DETECTION

CONDITION



The PCM calculates the actual catalyst warm up temperature during a cold start.
The PCM then compares the actual temperature to the expected catalyst
temperature model. The difference between the actual and expected temperatures
is a ratio. When this ratio exceeds the calibrated value this DTC is set and the
malfunction indicator lamp (MIL) illuminates.



Intake air restriction

2008 Mazda CX-9 Grand Touring

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

Microsoft

Sunday, November 15, 2009 10:08:38 AM

Page 245

© 2005 Mitchell Repair Information Company, LLC.

DIAGNOSTIC PROCEDURE

DTC P050E (MZI-3.7) DIAGNOSTIC PROCEDURE

POSSIBLE

CAUSE



Exhaust restriction



Mechanical concern with the engine



Throttle body malfunction



Vacuum leakage



PCM malfunction

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 RELATED PENDING CODE
OR STORED DTCs



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



Verify related pending code or stored
DTCs.



Is other DTCs present?

Yes

Go to the appropriate DTC troubleshooting. (See
DTC TABLE [MZI-3.7].)

No

Go to the next step.

4

INSPECT AIR CLEANER ELEMENT



Remove air cleaner element with the
engine running.



Is the engine speed increased?

Yes

Replace the air cleaner element, then go to Step
9.

No

Go to the next step.

5

INSPECT INTAKE AIR SYSTEM FOR
EXCESSIVE AIR SUCTION



Visually inspect the hose in intake air
system for looseness or damages.



Is there any malfunction?

Yes

Repair or replace the malfunctioning part, then
go to Step 9.

No

Go to the next step.

INSPECT THROTTLE BODY
PASSAGE

Yes

Clean or replace the throttle body passage, then
go to Step 9.

2008 Mazda CX-9 Grand Touring

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

Microsoft

Sunday, November 15, 2009 10:08:38 AM

Page 246

© 2005 Mitchell Repair Information Company, LLC.

DTC P053A [MZI-3.7]

DTC P053A (MZI-3.7) DETECTION CONDITIONS AND POSSIBLE CAUSES

6



Is the throttle body clogged?

No

Go to the next step.

7

INSPECT ENGINE COMPRESSION



Inspect the engine compression. (See
COMPRESSION INSPECTION
[MZI-3.7] .)



Is the engine compression normal?

Yes Go to the next step.

No

Overhaul the engine, then go to Step 9.

8

INSPECT FOR RESTRICTION IN
EXHAUST SYSTEM AND TWC



Is there any restriction?

Yes

Replace malfunctioning part, then go to the next
step.

No

Go to the next step.

9

VERIFY TROUBLESHOOTING OF
DTC P050E HAS BEEN COMPLETED



Verify that all disconnected
connectors are reconnected.



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



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



Perform the "KOEO and KOER self-
test". (See KOEO/KOER SELF
TEST [MZI-3.7].)



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.

10

VERIFY AFTER REPAIR
PROCEDURE



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



Are any DTCs present?

Yes

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

No

Troubleshooting completed.

DTC P053A

PCV valve heater control circuit/open

DETECTION

CONDITION



This DTC is set when the PCM detects a PCV valve heater circuit
malfunction.



Open circuit between PCV valve heater control terminal A and main relay
No.1

2008 Mazda CX-9 Grand Touring

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

Microsoft

Sunday, November 15, 2009 10:08:38 AM

Page 247

© 2005 Mitchell Repair Information Company, LLC.

POSSIBLE CAUSE



Open circuit between PCV valve heater fitting terminal A and main relay
No.1



Short to ground circuit between PCV valve heater control terminal B and
PCM terminal 2BL



Short to ground circuit between PCV valve heater fitting terminal B and PCM
terminal 2AU



Short to power circuit between PCV valve heater control terminal B and PCM
terminal 2BL



Short to power circuit between PCV valve heater fitting terminal B and PCM
terminal 2AU



Open circuit between PCV valve heater control terminal B and PCM terminal
2BL



Open circuit between PCV valve heater fitting B and PCM terminal 2AU



Connector or terminal malfunction



Damaged PCV heater assembly

2008 Mazda CX-9 Grand Touring

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

Microsoft

Sunday, November 15, 2009 10:08:39 AM

Page 248

© 2005 Mitchell Repair Information Company, LLC.