Content .. 38 39 40 41 ..

Mazda CX 7. Manual - part 40

ON-BOARD DIAGNOSTIC [L3 WITH TC]

01-02–115

01-02

End Of Sie

WM: DTC P03XX

DTC P0300[L3 WITH TC]

id010239806500

INSPECT WASTEGATE CONTROL SOLENOID
VALVE

• Inspect the wastegate control solenoid valve.

(See01-13-14 WASTEGATE CONTROL
SOLENOID VALVE INSPECTION[L3 WITH
TC].)

• Is there any malfunction?

Yes

Replace the wastegate control solenoid valve, then go to
Step 7.
(See01-13-5 INTAKE AIR SYSTEM REMOVAL/
INSTALLATION[L3 WITH TC].)

Go to the next step.

INSPECT PCM CONNECTOR FOR POOR
CONNECTION

• Turn the ignition switch off.

• Disconnect the PCM connector.

• Inspect for poor connection (such as damaged/

pulled-out pins, corrosion).

• Is there any malfunction?

Yes

Repair or replace the terminal, then go to Step 7.

Go to the next step.

INSPECT WASTEGATE CONTROL SOLENOID
VALVE CONTROL CIRCUIT FOR SHORT TO
POWER SUPPLY

• Turn the ignition switch to the ON position.

• Inspect for continuity between the wastegate

control solenoid valve terminal B (wiring
harness-side) and body ground.

• Is the voltage B+?

Yes

Repair or replace the wiring harness for a possible short to
power supply, then go to the next step.

Go to the next step.

VERIFY TROUBLESHOOTING OF DTC P0246
COMPLETED

• Make sure to reconnect all disconnected

connectors.

• Clear the DTC from the PCM memory using

the M-MDS.

• Start the engine.

• Is the same DTC present?

Yes

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

Go to the next step.

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 troubleshooting.
(See01-02-13 DTC TABLE[L3 WITH TC].)

DTC troubleshooting completed.

STEP

INSPECTION

ACTION

DTC P0300

Random misfire detected

DETECTION

CONDITION

• The PCM monitors the CKP sensor input signal interval time. The PCM calculates the change of interval

time for each cylinder. If the change of interval time exceeds the preprogrammed criteria, the PCM detects
a misfire in the corresponding cylinder. While the engine is running, the PCM counts the number of misfires
that occurred at 200 crankshaft revolutions and 1,000 crankshaft revolutions and calculates a misfire
ratio for each crankshaft revolution. If the ratio exceeds the preprogrammed criteria, the PCM determines
that a misfire, which can damage the catalytic converter or affect emission performance, has occurred.

Diagnostic support note

• This is a continuous monitor (Misfire).

• The MIL illuminates if the PCM detects a misfire which affects emission performance in two consecutive

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

• The MIL flashes if the PCM detects a misfire which can damage the catalytic converter during the first drive

cycle.

• PENDING CODE is available if the PCM detects a misfire which affects emission performance during the

first drive cycle.

• FREEZE FRAME DATA is available.

• DTC is stored in the PCM memory.

1871-1U-06B(01-02).fm 115 ページ２００６年３月１５日　水曜日　午前１０時３２分

ON-BOARD DIAGNOSTIC [L3 WITH TC]

01-02–116

Diagnostic procedure

POSSIBLE

CAUSE

• CKP sensor malfunction

• CMP sensor malfunction

• Ignition coil malfunction

• Ignition system malfunction

• MAF sensor contamination

• Excess air suction in intake air system (between MAF sensor and intake manifold)

• Fuel pump malfunction

• High pressure fuel pump malfunction

• Relief valve (built-in fuel delivery pipe) malfunction

• Spill valve control solenoid valve (built-in high pressure fuel pump) malfunction

• Improper fuel pump speed control operation

• Fuel pressure regulator (built-in fuel pump unit) malfunction

• Fuel line clogged

• Fuel filter clogged

• Fuel leakage in fuel line

• Fuel runout

• Poor quality fuel

• Purge control solenoid valve malfunction

• PCV valve malfunction

• EGR valve malfunction

• Vacuum hoses damage or improper connection

• Related connector and terminal malfunction

• Related wiring harness malfunction

• Insufficient compression

• Variable valve timing control system improper

STEP

INSPECTION

ACTION

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

• Have the FREEZE FRAME DATA and

DIAGNOSTIC MONITORING TEST RESULTS
(Misfire related) been recorded?

Yes

Go to the next step.

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

VERIFY RELATED REPAIR INFORMATION
AVAILABILITY

• Verify 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.

Go to the next step.

VERIFY RELATED PENDING CODE OR
STORED DTC

• Turn the ignition switch off then to the ON

position (Engine off).

• Verify related pending code or stored DTCs.

• Are other DTCs present?

Yes

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

Go to the next step.

VERIFY CURRENT INPUT SIGNAL STATUS
(KEY TO ON/IDLE)

• Access APP1, APP2, ECT, IAT, MAF, RPM, TP,

and VSS PIDs using the M-MDS.
(See01-40-6 PCM INSPECTION[L3 WITH
TC].)

• Is there any signal that is far out of specification

when the ignition switch is turned to the ON
position and the engine idles?

Yes

Inspect the suspected circuit and/or part according to the
inspection results.
(See01-40-6 PCM INSPECTION[L3 WITH TC].)
Then go to Step 26.

Go to the next step.

VERIFY CURRENT INPUT SIGNAL STATUS
UNDER TROUBLE CONDITION

• Inspect the same PIDs as in Step 4 while

simulating FREEZE FRAME DATA condition.

• Is there any signal which causes drastic

changes?

Yes

Inspect the suspected circuit and/or part according to the
inspection results.
(See01-40-6 PCM INSPECTION[L3 WITH TC].)
Then go to Step 26.

Go to the next step.

INSPECT CMP SENSOR

• Inspect the CMP sensor.

(See01-40-45 CAMSHAFT POSITION (CMP)
SENSOR INSPECTION[L3 WITH TC].)

• Is the CMP sensor normal?

Yes

Go to the next step.

Inspect the installation condition for damage to the timing
chain and gears, repair the malfunctioning part.

• If it is normal, replace the CMP sensor.

Then go to Step 26.

DTC P0300

Random misfire detected

1871-1U-06B(01-02).fm 116 ページ２００６年３月１５日　水曜日　午前１０時３２分

ON-BOARD DIAGNOSTIC [L3 WITH TC]

01-02–117

01-02

VERIFY CKP SENSOR INSTALLATION
CONDITION

• Inspect the CKP sensor for looseness.

• Is the CKP sensor loose?

Yes

Retighten the CKP sensor, then go to Step.

Go to the next step.

INSPECT IGNITION COIL HARNESSES

• Inspect the ignition coil related wiring harness

condition (intermittent open or short) for all
cylinders.

• Are wiring harness conditions normal?

Yes

Go to the next step.

Repair the suspected wiring harnesses, then go to Step 26.

INSPECT IGNITION SYSTEM OPERATION

• Carry the out spark test.

(See01-03-78 ENGINE CONTROL SYSTEM
OPERATION INSPECTION[L3 WITH TC])

• Is a strong blue spark visible at each cylinder?

Yes

Go to the next step.

Repair or replace the malfunctioning part according to the
spark test result.
Then go to Step 26.

INSPECT MAF PID

• Start the engine.

• Access the MAF PID using the M-MDS.

• Race the engine and verify that the MAF PID

changes quickly according to the change in the
engine speed.

• Is the MAF PID response normal?

Yes

Go to the next step.

Replace the MAF sensor, then go to Step 26.

INSPECT IN INTAKE AIR SYSTEM FOR
EXCESSIVE AIR SUCTION

• Inspect for air leakage at the following:

— Between the MAF sensor and throttle body

— Between throttle body and intake manifold

• Is there any malfunction?

Yes

Repair or replace suspected part, then go to Step 26.

Go to the next step.

INSPECT FUEL LINE PRESSURE

• Inspect fuel line pressure.

(See01-14-5 FUEL LINE PRESSURE
INSPECTION[L3 WITH TC].)

• Is the fuel line pressure normal?

Yes

Go to Step 14.

If the fuel line pressure is too low, go to the next step.
If the fuel line pressure is too high, replace the fuel pump
unit,
then go to Step 26.

INSPECT FUEL LINE FROM FUEL PUMP TO
FUEL DELIVERY PIPE

• Visually inspect fuel line for fuel leakage.

• Is there any fuel leakage?

Yes

Replace suspected fuel line, then go to Step 20.

Inspect the fuel filters for following:

• Foreign material or stain inside fuel filter (low-pressure

side)

Perform following actions depend on the result above.

• If foreign materials or stain is found inside fuel filter

(low-pressure side), clean the fuel tank and filter (low-
pressure side).

• If normal, replace the fuel pump unit.

Then, go to Step 26.

INSPECT ENGINE COMPRESSION

• Inspect the engine compression.

(See01-10-9 COMPRESSION
INSPECTION[L3 WITH TC].)

• Is it normal?

Yes

Go to the next step.

Perform engine overhaul for repairs, then go to Step 26.

INSPECT VARIABLE VALVE TIMING CONTROL
SYSTEM OPERATION

• Inspect variable valve timing control system

operation.
(See01-03-78 ENGINE CONTROL SYSTEM
OPERATION INSPECTION[L3 WITH TC])

• Does the variable valve timing control system

work properly?

Yes

Go to the next step.

Repair or replace the malfunctioning part according to the
variable valve timing control system inspection results, then
go to Step 26.

STEP

INSPECTION

ACTION

1871-1U-06B(01-02).fm 117 ページ２００６年３月１５日　水曜日　午前１０時３２分

ON-BOARD DIAGNOSTIC [L3 WITH TC]

01-02–118

INSPECT OPERATION OF PURGE CONTROL
SOLENOID VALVE

• Turn the ignition switch off.

• Connect the vacuum pump to the purge control

solenoid valve and apply vacuum to the
solenoid.

• Verify that the solenoid holds vacuum.

• Turn the ignition switch to the ON position

(Engine off).

• Access EVAPCP PID in the SIMULATION

TEST using the M-MDS.

• Set duty value to 100% for the EVAPCP PID.

• Apply vacuum while turning the solenoid from

OFF to ON and simulating the EVAPCP PID
with a 100% duty value.

• Verify that the solenoid releases vacuum while

the solenoid is turned on.

• Is the purge control solenoid valve operation

normal?

Yes

Go to the next step.

Replace the purge control solenoid valve, then go to Step
26.

INSPECT PCV VALVE OPERATION

• Turn the ignition switch off.

• Remove the PCV valve and inspect the valve

operation.
(See01-16-14 POSITIVE CRANKCASE
VENTILATION (PCV) VALVE INSPECTION[L3
WITH TC].)

• Is the PCV valve operation normal?

Yes

Replace the PCV valve, then go to Step 26.

Go to the next step.

INSPECT OPERATION OF EGR VALVE

• Remove the EGR valve.

• Visually inspect the if EGR valve is stuck open.

• Is the EGR valve stuck open?

Yes

Repair or replace the EGR valve, then go to Step 26.

Go to the next step.

VERIFY FUEL PUMP SPEED CONTROL
OPERATION

• Perform Fuel Pump Speed Control Inspection.

(See01-03-78 ENGINE CONTROL SYSTEM
OPERATION INSPECTION[L3 WITH TC].)

• Does the fuel pump speed control work

properly?

Yes

Go to the next step.

Inspect or replace the malfunctioning parts, according to
inspection results.
Then go to Step 26.

INSPECT FUEL PRESSURE (HIGH-SIDE)

• Access and monitor the FUEL_PRES PID.

• Is the FUEL_PRES PID value within the

specification?
(See01-40-6 PCM INSPECTION[L3 WITH
TC].)

Yes

Go to Step 24.

Go to the next step.

IDENTIFY CAUSE BY FUEL PRESSURE
SENSOR OR HIGH PRESSURE FUEL PUMP

• Is the vehicle accelerate performance

normally?

Yes

Go to the next step.

Go to Step 23.

INSPECT FUEL PRESSURE SENSOR

• Inspect the fuel pressure sensor.

(See01-40-35 FUEL PRESSURE SENSOR
INSPECTION[L3 WITH TC].)

• Is the fuel pressure sensor normal?

Yes

Go to the next step.

Replace the fuel delivery pipe, then go to Step 26.

INSPECT HIGH PRESSURE FUEL PUMP

• Replace the high pressure fuel pump

• Monitor FUEL_PRES PID

• Is the FUEL_PRES PID value within the

specified?
(See01-40-6 PCM INSPECTION[L3 WITH
TC].)

Yes

Go to Step 26.

Go to the next step.

STEP

INSPECTION

ACTION

1871-1U-06B(01-02).fm 118 ページ２００６年３月１５日　水曜日　午前１０時３２分

Content .. 38 39 40 41 ..