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Diagnostic procedure

WARNING: This page is about a different car, the 2009 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.
STEP INSPECTION RESULTS ACTION
1 Warm up the engine.
Idle the engine for 5 min. 
Does the symptom disappear?		 Yes Troubleshooting is completed. (Cause of this symptom is that the idle learning for electronic throttle control system is not completed.)
No Go to the next step.
2 Verify the following.
  • External fuel shut off or accessory (such as kill switch, alarm)
  • Fuel quality (such as proper octane, contamination, winter/summer blend)
  • No air leakage from intake air system
  • Proper sealing of intake manifold and components attached to intake manifold EGR valve
  • Ignition wiring
  • Electrical connections
  • Fuses
  • Smooth operation of throttle valve
  • PCM ground circuit (1E, 1F, 1G, 1 BE, or 1BF)

Are all items normal?		 Yes Go to the next step.
No Service if necessary.
Repeat Step 2.
3 Connect the M-MDS to the DLC-2.
Switch the ignition to ON (Engine off)
Retrieve any DTCs
Are there any DTCs displayed?		 Yes DTC is displayed: 
Go to the appropriate DTC inspection.
(See DTC TABLE [L5] .)
No No DTC is displayed: 
Go to the next step.
4 Is the engine overheating? Yes Go to symptom troubleshooting "No. 17 Cooling system concerns - Overheating".
(See NO. 17 COOLING SYSTEM CONCERNS-OVERHEATING [L5] )
No Go to the next step.
5 Connect the M-MDS to the DLC-2.
Access MAF PID
Drive vehicle while monitoring the PID Is the MAF PID within the specification?		 Yes Go to the next step.
No Inspect for an open or short circuit in the MAF sensor and related wiring harness.
6
NOTE:
  • The following test is for engine running at rough idle with A/C on If other symptoms exist, go to the next step.
Connect a pressure gauge to the A/C low and high pressure side lines.Start the engine and idle it.Turn the A/C switch on.Measure the low side and high side pressures.Are the pressures within the specifications?(See REFRIGERANT PRESSURE CHECK )		 Yes Go to the next step.
No If the A/C is always on, go to symptom troubleshooting "No. 24 A/C is always on or A/C compressor runs continuously".
(See NO. 24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [L5] .)
For other symptoms, inspect the following:
  • Refrigerant charging amount
  • Condenser fan operation
7 Visually inspect the CKP sensor and teeth of the crankshaft pulley.
(See CRANKSHAFT POSITION (CKP) SENSOR INSPECTION [L5] .)
Are the CKP sensor and teeth of the crankshaft pulley normal?		 Yes Go to the next step.
No Replace the malfunctioning part.
8 Inspect the ignition coil related wiring harness condition (intermittent open or short circuit) for all cylinders Are the wiring harness conditions normal? Yes Go to the next step.
No Repair the wiring harnesses.
9 Inspect the spark plug condition.
(See SPARK PLUG INSPECTION [L5] .)
Is the spark plug wet, covered with carbon or grayish white?		 Yes Spark plug is wet or covered with carbon: 
Inspect for fuel leakage from the injector.
Spark plug is grayish white: 
Inspect the fuel injector for clogging.
No Install the spark plugs on original cylinders.
Go to the next step.
10 Access the PSP PID using the M-MDS.
Do the PIDs indicate the correct values under trouble condition?		 Yes Go to the next step
No Inspect and repair or replace power steering pressure switch and the related harnesses.
(See POWER STEERING PRESSURE (PSP) SWITCH INSPECTION [L5] .)
If the malfunction remains, perform the intermittent concern troubleshooting procedure
(See INTERMITTENT CONCERN TROUBLESHOOTING [L5] )
11 Perform the electronic throttle control system operation inspection.
(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L5] .)
Does the electronic throttle control system function properly?		 Yes Go to the next step
No Repair or replace the malfunctioning part according to the electronic throttle control system operation inspection results
12 Inspect the fuel line pressure
(See FUEL LINE PRESSURE INSPECTION [L5] .)
Is the fuel line pressure correct?		 Yes Go to the next step
No Low: 
Inspect the fuel line for clogging
If there is no malfunction, replace fuel pump unit.
High: 
Replace the fuel pump unit.
(See FUEL PUMP UNIT REMOVAL/INSTALLATION [L5] .)
13 Visually inspect for fuel leakage at the fuel injector, O-ring, and fuel line
Service if necessary
Does the fuel line pressure hold after the ignition is off?
(See FUEL LINE PRESSURE INSPECTION [L5] .)		 Yes Go to the next step
No Inspect the fuel injector
(See FUEL INJECTOR INSPECTION [L5] .) If the fuel injector is normal, replace the fuel pump unit.
(See FUEL PUMP UNIT REMOVAL/INSTALLATION [L5] .)
14 Connect the M-MDS to the DLC-2
Start the engine and idle it
Access the LONG FT1 PID
Measure the LONG FT1 PID at idle.
Is the PID value between -14% and +14%? 		 Yes Go to the next step
No LONG FT1 PID is out of specification.
Less than specification (too rich):
  • Inspect the EVAP control system

Greater than specification (too lean):
  • Inspect for air leakage at the intake air system components
    • If the system is normal, go to the next step.
15 Disconnect the vacuum hose between the purge solenoid valve and the intake manifold from the purge solenoid valve side.
Plug the open end of the vacuum hose.
Start the engine.
Does the engine condition improve?		 Yes Check if the purge solenoid valve is stuck open mechanically
Inspect the EVAP control system
No Go to the next step
16 Remove and shake the PCV valve
Does the PCV valve rattle?		 Yes Go to the next step
No Replace the PCV valve
(See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [L5] .)
17 Visually inspect the exhaust system parts.
(See EXHAUST SYSTEM INSPECTION [L5] .)
Is there any deformed exhaust system parts?		 Yes Replace the suspected part
No Go to the next step
18 Visually inspect the CMP sensor and teeth of the camshaft.
(See CAMSHAFT POSITION (CMP) SENSOR INSPECTION [L5] .)
Are the CMP sensor and teeth of the camshaft normal?		 Yes Go to the next step
No Replace the malfunctioning part.
19 Inspect the engine condition while tapping the EGR valve housing
Does the engine condition improve?		 Yes Replace the EGR valve
(See EGR VALVE REMOVAL/INSTALLATION [L5] .)
No Go to the next step
20 Inspect the variable valve timing control system operation
(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L5] )
Does variable valve timing control system function properly?		 Yes Go to the next step
No Repair or replace the malfunctioning part
21 Is the engine compression correct?
(See COMPRESSION INSPECTION [L5] .)		 Yes Inspect the valve timing.
No Inspect for causes
22 Verify test results
  • If normal, return to the diagnostic index to service any additional symptoms.

    (See SYMPTOM DIAGNOSTIC INDEX [L5] .)

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