Mazda CX 7. Manual — part 91

SYMPTOM TROUBLESHOOTING [L3 WITH TC]

01-03–61

01-03

End Of Sie

NO.18 COOLING SYSTEM CONCERNS-RUNS COLD[L3 WITH TC]

id010339802400

Diagnostic procedure

9

Cool down the engine.
Remove the thermostat and inspect operation.
(See01-12-11 THERMOSTAT REMOVAL/
INSTALLATION[L3 WITH TC].)
(See01-12-11 THERMOSTAT INSPECTION[L3
WITH TC].)
Is thermostat normal?

Yes

Thermostat is normal.
Inspect the cylinder block for leakage or blockage.

No

Access the ECT PID using the M-MDS.
Inspect for both ECT PID and temperature gauge
readings.
If the temperature gauge on instrument cluster
indicates normal but ECT PID is not same as
temperature gauge reading, inspect the ECT sensor.
(See01-03-78 ENGINE CONTROL SYSTEM
OPERATION INSPECTION[L3 WITH TC].)
If the temperature gauge on instrument cluster
indicates overheating but ECT PID is normal, inspect
the instrument cluster.
(See09-22-3 INSTRUMENT CLUSTER INSPECTION.)

10

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

18

COOLING SYSTEM CONCERNS - RUNS COLD

DESCRIPTION

Engine takes excessive time to reach normal operating temperature.

POSSIBLE CAUSE

• Thermostat malfunction

• Condenser fan system malfunction

• Cooling fan system malfunction

STEP

INSPECTION

RESULTS

ACTION

1

Is customer complaint “Lack of passenger
compartment heat” only?

Yes

Inspect the A/C heater system.

No

Go to the next step.

2

Does the engine speed continue at fast idle?

Yes

Go to symptom troubleshooting “NO.9 FAST IDLE/
RUNS ON.”
(See01-03-37 NO.9 FAST IDLE/RUNS ON[L3 WITH
TC].)

No

Go to the next step.

3

Cool down the engine.
Remove the thermostat and inspect operation.
(See01-12-11 THERMOSTAT REMOVAL/
INSTALLATION[L3 WITH TC].)
(See01-12-11 THERMOSTAT INSPECTION[L3
WITH TC].)
Is thermostat normal?

Yes

Go to the next step.

No

Replace the thermostat.

4

Perform the Cooling Fan Control System
Operation Inspection.
(See01-03-78 ENGINE CONTROL SYSTEM
OPERATION INSPECTION[L3 WITH TC].)
Does the cooling fan system operate properly?

Yes

Access the ECT PID using the M-MDS.
Inspect for both ECT PID and temperature gauge
readings.
If the temperature gauge on instrument cluster
indicates normal but ECT PID is not same as
temperature gauge reading, inspect the ECT sensor.
(See01-40-25 ENGINE COOLANT TEMPERATURE
(ECT) SENSOR INSPECTION[L3 WITH TC].)
If the temperature gauge on instrument cluster
indicates overheating but ECT PID is normal, inspect
the instrument cluster.
(See09-22-3 INSTRUMENT CLUSTER INSPECTION.)

No

Repair or replace malfunctioning part, according to
inspection results.

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SYMPTOM TROUBLESHOOTING [L3 WITH TC]

01-03–62

End Of Sie

NO.19 EXCESSIVE BLACK SMOKE[L3 WITH TC]

id010339802500

Diagnostic procedure

5

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

19

EXHAUST SMOKE

DESCRIPTION

Blue, black, or smoke from the exhaust system

POSSIBLE CAUSE

Blue smoke (Burning oil):

• PCV valve malfunction

• Engine internal oil leakage

• Oil leakage at the compressor or turbine end of the turbocharger

White smoke (Water in combustion):

• Cooling system malfunction (coolant loss)

• Engine internal coolant leakage

• Coolant leakage at the compressor or the turbine end of the turbocharger

Black smoke (Rich fuel mixture):

• Air cleaner restriction

• Intake-air system is collapsed or restricted

• Leakage at engine intake or exhaust manifold

• Wastegate valve malfunction (stuck open)

• Excessive fuel pressure

• Improper engine compression

• Ignition system malfunction

• Improper fuel injection timing and amount

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.

STEP

INSPECTION

RESULTS

ACTION

1

What color is smoke coming from the exhaust
system?

Blue

Burning oil is indicated.
Go to the next step.

White

Water in combustion is indicated.
Go to the Step 5.

Black

Rich fuel mixture is indicating.
Go to the Step 6.

2

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

Yes

Go to the next step.

No

Replace the PCV valve.

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SYMPTOM TROUBLESHOOTING [L3 WITH TC]

01-03–63

01-03

3

Remove the parts necessary to inspect
turbocharger without removing the turbocharger.
Visually inspect for the turbocharger compressor
housing.
Is any engine oil found inside turbocharger
compressor housing?

Yes

Install all parts removed in this step.
Perform the following, according to inspection
results. Excessive amount of oil is found:
Replace the turbocharger.
Small amount of oil is found:
Wipe oil out of vehicle, then Go to the next step.

No

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

4

Inspect for the following engine internal parts.

• Damaged valve guide, stems or valve seals

• Blocked oil drain passage in cylinder head

• Piston ring is not seated, seized or worn

• Damage cylinder bore

Are there ant problem found?

Yes

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

No

Engine internal parts are normal.
If other driveability symptoms are present, return to
diagnostic index to service additional symptoms.

5

Does cooling system hold the coolant pressure?
(See01-12-6 ENGINE COOLANT LEAKAGE
INSPECTION[L3 WITH TC].)

Yes

Inspect for the following:

• Cylinder head gasket leakage

• Intake manifold gasket leakage

• Cracked or porous engine block

If other driveability symptoms are present, return to
diagnostic index to service additional symptoms.

No

Inspect for the cause.

6

Inspect for the following for intake-air system.

• Air cleaner restriction

• Collapsed or restricted

• Leakage

Are all items normal?

Yes

Go to the next step.

No

Repair or replace the suspected part.

7

Connect the M-MDS to the DLC-2.
Access following PIDs.

• ECT

• MAF

• IAT

• IAT2

• APP

• TP

• MAP

• VSS

• O2S11

• O2S12

• LONGFT1

• SHTFT1

Monitor the PIDs under the black smoke
appeared engine condition.
Do all PID indicate normal according to engine
conditions?

Yes

Go to the next step.

No

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

8

Inspect the wastegate.
(See01-13-16 WASTEGATE ACTUATOR
INSPECTION[L3 WITH TC].)
Does the wastegate stuck open?

Yes

Perform the wastegate control system operation
inspection.
(See01-03-78 ENGINE CONTROL SYSTEM
OPERATION INSPECTION[L3 WITH TC].)
Repair or replace malfunctioning part according to the
inspection results.

No

Go to the next step.

STEP

INSPECTION

RESULTS

ACTION

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SYMPTOM TROUBLESHOOTING [L3 WITH TC]

01-03–64

End Of Sie

9

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

• ECT

• MAF

• IAT

• IAT2

• APP

• TP

• MAP

• VSS

• O2S11

• O2S12

• LONGFT1

• SHTFT1

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

Yes

Go to the next step.

No

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].)

10

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 14.

No

Go to the next step.

11

Is vehicle accelerate performance normally?

Yes

Go to the next step.

No

Go to Step 13.

12

Inspect the fuel pressure sensor.
(See01-40-35 FUEL PRESSURE SENSOR
INSPECTION[L3 WITH TC].)
Is the fuel pressure sensor normal?

Yes

Go to Step 14.

No

Replace the delivery pipe.

13

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.
Retest Step 16.

No

Go to the next step.

14

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.

No

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

15

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

Yes

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

No

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.

16

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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