Mazda CX 7. Manual - part 87

SYMPTOM TROUBLESHOOTING [L3 WITH TC]

01-03–45

01-03

End Of Sie

Perform the 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.

Inspect or replace the malfunctioning parts, according
to the inspection results.

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 27.

Go to the next step.

Is the vehicle accelerate performance normally?

Yes

Go to the next step.

Go to Step.26.

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 Step 27.

Replace the delivery pipe.

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.

Connect the fuel pressure gauge between the
fuel pump and the 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 with in 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 the 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 the suspected fuel injector.
(See01-14-23 FUEL INJECTOR REMOVAL/
INSTALLATION[L3 WITH TC].)

Measure the 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]

01-03–46

NO.12 LACK/LOSS OF POWER (ACCELERATION/CRUISE)[L3 WITH TC]

id010339801800

LACK/LOSS OF POWER (ACCELERATION/CRUISE)

DESCRIPTION

Performance is poor under load (e.g., powers down when climbing hills).

POSSIBLE CAUSE

• Improper A/C system operation

• Improper operation of A/C cut-off control

• Air leakage or restriction from intake-air system

• Loose turbocharger compressor-to-intake manifold duct connecting

• Turbocharger rotating assembly binding or dragging

• Wastegate valve malfunction (stuck open)

• Turbocharger malfunction

• Charge air cooler malfunction

• Variable swirl system malfunction

• Improper operation of electronic throttle control system

• Purge solenoid valve malfunction

• EGR system malfunction

• Brake dragging

• Low engine compression

• Poor fuel quality

• Vacuum leakage

• Incorrect signal to ignition coil

• Spark plug malfunction

• Engine overheating

• Throttle body malfunction

• Air cleaner restriction or dirty

• PCV valve malfunction

• Improper valve timing due to jumping out of timing chain

• Improper operation of variable valve timing control system

• Restriction in exhaust system or three-way catalytic converter (TWC)

• Leakage at exhaust manifold or turbocharger mounting flange

• Intermittent open or short fuel pump related circuit

• Inadequate fuel pressure (high-or low pressure side)

• Fuel pressure sensor or related circuit malfunction

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

• Relief valve malfunction (built-in delivery pipe)

• High pressure fuel pump malfunction

• Improper fuel pump speed control operation

• Fuel pump mechanical malfunction

• Fuel line restriction or clogging

• Fuel injector malfunction

• Incorrect fuel injection timing

• Erratic signal from CKP sensor

• Erratic or no signal from CMP sensor

• ECT sensor or related circuit malfunction

• Manifold absolute pressure (MAP) sensor or related circuit malfunction

• Accelerator position sensor or related circuit malfunction

• MAF/IAT sensor or related circuit malfunction

• IAT sensor No.2 or related circuit malfunction

• Intermittent open or short circuit MAF sensor, accelerator position sensor, TP sensor and VSS

• ATX 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]

01-03–47

01-03

Diagnostic procedure

STEP

INSPECTION

RESULTS

ACTION

Verify the following:

• Fuel quality (proper octane, contamination,

winter/summer blend)

• Air cleaner restriction or dirty

• Intake-air system restriction or leakage

• Charge air cooler condition (restriction or

damaged)

• Turbocharger compressor-to-intake manifold

duct loose connection

• Leakage at exhaust manifold or turbocharger

mounting flange

• Vacuum leakage

• Clutch slippage

• Brake dragging

Are all items normal?

Yes

Go to the next step.

Service if necessary.
Repeat Step 1.

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.

Is the engine overheating?

Yes

Go to symptom troubleshooting “NO.17 COOLING
SYSTEM CONCERN-OVERHEATING.”
(See01-03-60 NO.17 COOLING SYSTEM
CONCERNS-OVERHEATING[L3 WITH TC].)

Go to the next step.

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.

Inspect or replace the malfunctioning parts, according
to the inspection results.

Perform the A/C Cut-off Operation Inspection.
(See01-03-78 ENGINE CONTROL SYSTEM
OPERATION INSPECTION[L3 WITH TC].)
Does the A/C Cut-off Operation work properly?

Yes

Go to the next step.

Repair or replace malfunctioning parts, according to
the inspection results.

Perform the TP sweep inspection.
(See01-03-78 ENGINE CONTROL SYSTEM
OPERATION INSPECTION[L3 WITH TC].)
Does the variable swirl system work properly?

Yes

Visually inspect throttle body (damaged/scratching.) If
normal, go to the next step.

Inspect or replace the malfunctioning parts, according
to the inspection results.

Perform the Variable Swirl Control System
Operation Inspection.
(See01-03-78 ENGINE CONTROL SYSTEM
OPERATION INSPECTION[L3 WITH TC].)

Yes

Go to the next step.

Inspect or replace the malfunctioning parts, according
to the inspection results.

Perform the Variable Valve Timing Control
System Operation Inspection.
(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.

Inspect or replace the malfunctioning parts, according
to the inspection results.

Perform the Purge Control System Operation
Inspection.
(See01-03-78 ENGINE CONTROL SYSTEM
OPERATION INSPECTION[L3 WITH TC].)
Does the purge control system work properly?

Yes

Go to the next step.

Inspect or replace the malfunctioning parts, according
to the inspection results.

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 the inspection results.

Perform the Wastegate Control System
Operation Inspection.
(See01-03-78 ENGINE CONTROL SYSTEM
OPERATION INSPECTION[L3 WITH TC].)
Does the wastegate control system work
properly?

Yes

Go to the next step.

Inspect or replace the malfunctioning parts, according
to the inspection results.

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SYMPTOM TROUBLESHOOTING [L3 WITH TC]

01-03–48

Connect the M-MDS to DLC-2.
Access and monitor following PIDs using the
data monitor function.

• ECT

• MAF

• IAT

• IAT2

• APP

• TP

• MAP

• FP (Low side pressure line)

• VSS

Do the PIDs indicate correct values under
trouble condition?
(See01-40-6 PCM INSPECTION[L3 WITH TC].)

Yes

Go to the next step.

Inspect and repair or replace suspected parts and
related harnesses.
If the malfunction remains, perform the intermittent
concern troubleshooting procedure.
(See01-03-76 INTERMITTENT CONCERN
TROUBLESHOOTING[L3 WITH TC].)

Inspect CMP and CKP sensor for following;

• Installation condition

(See01-40-45 CAMSHAFT POSITION
(CMP) SENSOR REMOVAL/
INSTALLATION[L3 WITH TC].)
(See01-40-42 CRANKSHAFT POSITION
(CKP) SENSOR REMOVAL/
INSTALLATION[L3 WITH TC].)

• Damaged trigger wheel and camshaft

• Open or short circuit in wiring harnesses Is

there any malfunction detected?

Yes

Repair or replace the malfunctioning part according to
the inspection results.

Go to the next step.

Remove and shake PCV valve.
Does the PCV valve rattle?

Yes

Go to the next step.

Replace the PCV valve.

Inspect spark plug condition.
Is spark plug wet, covered with carbon or grayish
white?

Yes

Spark plug is wet or covered with carbon:
Perform the Spark Test and repair or replace
malfunctioning part according to inspection result.
(See01-03-78 ENGINE CONTROL SYSTEM
OPERATION INSPECTION[L3 WITH TC].)
Spark plug is grayish white:
Go to Step 23.

Install spark plugs on original cylinders.
Go to the next step.

Inspect for restriction in exhaust system and
three-way catalytic converter (TWC).
Is there any restriction?

Yes

Replace malfunctioning part.

Go to the next step.

Remove parts necessary to inspect
turbocharger without removing the turbocharger.
Inspect if turbocharger compressor wheel is
bent, damaged, or interfering with housing on
vehicle.
(See01-13-17 TURBOCHARGER
INSPECTION[L3 WITH TC].)
Is there any problem?

Yes

Replace turbocharger.

Go to the next step.

Inspect turbocharger compressor wheel locknut
is loose or has fallen down inside turbocharger.
Is there any problem?

Yes

Replace turbocharger.

Go to the next step.

Inspect turbocharger compressor wheel by
hand.
Does wheel turn easily and smoothly?

Yes

Go to the next step.

Replace turbocharger.

Inspect turbocharger turbine wheel is damaged,
cracked or interfering with housing on vehicle.

Note

• Inspect all fins on each turbine wheel.

Is there any problem?

Yes

Replace turbocharger.

Go to the next step.

Is any engine oil found inside turbocharger
turbine housing?

Yes

Excessive amount of oil is found:
Replace turbocharger.
Small amount of oil is found:
Wipe oil out of vehicle, then Go to the next step.

Go to the next step.

STEP

INSPECTION

RESULTS

ACTION

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