Mazda CX 7. Manual — part 88

SYMPTOM TROUBLESHOOTING [L3 WITH TC]

01-03–49

01-03

End Of Sie

Is any engine oil found inside turbocharger
compressor housing?

Yes

Wipe oil out vehicle and install all removed parts in
Step 16. Then, Go to the next step.

Turbocharger is normal.
Install all parts removed in Step 17.
Then, Go to the next step.

Inspect for leakage in fuel line.
Is there any fuel leakage found?

Yes

Repair or replace suspected part.

Go to the next step.

Access and monitor FUEL_PRES PID.
Is the FUEL_PRES PID value within the
specification?
(See01-40-6 PCM INSPECTION[L3 WITH TC].)

Yes

Go to Step 27.

Go to the next step.

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

Troubleshooting is completed.
Go to Step 30.

Go to the next step.

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 delivery pipe.

Connect the fuel pressure gauge between fuel
pump and high pressure fuel pump.
Measure the fuel pressure line of the low
pressure side.
(See01-14-5 FUEL LINE PRESSURE
INSPECTION[L3 WITH TC].)
Is the fuel pressure within the specification?

Yes

Go to the next step.

Inspect for the following:

• Fuel line restriction

• Fuel filter clogging

If normal replace the fuel pump.

Inspect fuel injector for each cylinder.
(See01-14-27 FUEL INJECTOR
INSPECTION[L3 WITH TC].)
Are fuel injectors normal?

Yes

Go to the next step.

Replace suspected fuel injector.
(See01-14-23 FUEL INJECTOR REMOVAL/
INSTALLATION[L3 WITH TC].)

Measure compression pressure for each
cylinder.
(See01-10-9 COMPRESSION INSPECTION[L3
WITH TC].)
Are compression pressures within the
specification?

Yes

Replace the injector driver module.
If the problem remains, overhaul the engine.

Inspect for the following:

• Damaged valve seat

• Worn valve stem and valve guide

• Worn or stuck piston ring

• Worn piston, piston ring or cylinder

• Improper valve timing

Service if necessary.

Verify test results.

• If normal, return to the diagnostic index to service any additional symptoms.

• If a malfunction remains, inspect the related Service Bulletins and/or On-line Repair Information and perform the

repair or diagnosis.
— If the vehicle is repaired, troubleshooting is completed.

— If the vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later

calibration is available. Retest.

STEP

INSPECTION

RESULTS

ACTION

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SYMPTOM TROUBLESHOOTING [L3 WITH TC]

01-03–50

NO.13 KNOCKING/PINGING[L3 WITH TC]

id010339801900

KNOCKING/PINGING

DESCRIPTION

Sound is produced when air/fuel mixture is ignited by something other than a spark plug (e.g., hot spot in
the combustion chamber).

POSSIBLE CAUSE

• Poor fuel quality

• Engine overheating due to cooling system malfunction

• Variable swirl valve stuck closed

• Improper operation of electronic throttle system

• Air leakage or restriction from intake-air system

• ECT sensor or related circuit malfunction

• MAF sensor or related circuit malfunction

• IAT sensor No.1 or related circuit malfunction

• IAT sensor No.2 or related circuit malfunction

• Incorrect fuel injection timing or amount

• Fuel injector malfunction

• Knock sensor or related circuit malfunction

• Ignition system malfunction

• Erratic signal from CMP sensor

• Inadequate engine compression

• Inadequate fuel pressure (high-pressure side)

• Manifold absolute pressure (MAP) sensor or related malfunction

• Wastegate valve malfunction (stuck closed)

• Charge air cooler malfunction

• Fuel pressure sensor or related circuit malfunction

• Accelerator position sensor or related circuit malfunction

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

• Exhaust system and/or three-way catalytic converter (TWC) restriction

• EGR system malfunction

Warning
The following troubleshooting flow chart contains the fuel system diagnosis and repair
procedures. Read the following warnings before performing the fuel system services:

• Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always

keep sparks and flames away from fuel.

• Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injury or

death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete
“BEFORE REPAIR ROCEDURE” and “AFTER REPAIR PROCEDURE” described in this
manual.
(See01-14-4 BEFORE REPAIR PROCEDURE[L3 WITH TC].)
(See01-14-4 AFTER REPAIR PROCEDURE[L3 WITH TC].)

Caution

• Disconnecting/connecting the quick release connector without cleaning it may possibly

cause damage to the fuel pipe and quick release connector. Always clean the quick release
connector joint area before disconnecting/connecting, and make sure that it is free of
foreign material.

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SYMPTOM TROUBLESHOOTING [L3 WITH TC]

01-03–51

01-03

Diagnostic procedure

STEP

INSPECTION

RESULTS

ACTION

Connect the M-MDS to the DLC-2.
Access the ECT PID.
Verify that the ECT PID is less than 116

°C

{241

°F} during driving.

Is ECT PID less than specified?

Yes

Go to the next step.

The cause of this concern could be from the cooling
system overheating.
Perform the symptom troubleshooting “NO.17
COOLING SYSTEM CONCERNS - OVERHEATING.”
(See01-03-60 NO.17 COOLING SYSTEM
CONCERNS-OVERHEATING[L3 WITH TC].)

Inspect for the following:

• Air leakage or restriction from intake-air

system

• Fuel quality (proper octane, contamination,

winter/summer blend)

• Exhaust system and/or three-way catalytic

converter (TWC) restriction

• Charge air cooler condition (restriction or

damaged)

Are all items normal?

Yes

Go to the next step.

Service if necessary.
Repeat Step 2.

Perform the self-test function using the M-MDS.
Turn the ignition switch to the ON position.
Retrieve any DTCs.
Is a DTC displayed?

Yes

DTC is displayed:
Go to the appropriate DTC test.
(See01-02-13 DTC TABLE[L3 WITH TC].)

No DTC is displayed:
Go to the next step.

Inspect the knock sensor.
(See01-40-47 KNOCK SENSOR (KS)
INSPECTION[L3 WITH TC].)
Is the knock sensor normal?

Yes

Go to the next step.

Replace the knock sensor.
(See01-40-47 KNOCK SENSOR (KS) REMOVAL/
INSTALLATION[L3 WITH TC]

Perform the EGR system operation inspection.
(See01-03-78 ENGINE CONTROL SYSTEM
OPERATION INSPECTION[L3 WITH TC].)
Does the EGR system operate properly?

Yes

Go to the next step.