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Home >> Mazda >> 2011 >> 6 s Touring Plus >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 3 (Symptom Troubleshooting [Engine Mechanical MZR 2.5]) >> No. 5 Engine Stalls-After Start/At Idle >> Diagnostic procedure

Diagnostic procedure

WARNING: This page is about a different variant/trim than selected.
DIAGNOSTIC PROCEDURE CHART

STEP INSPECTION RESULTS ACTION
1 INSPECT RELATED PART CONDITION 
  • Inspect the following:
    • Vacuum connection
    • Air cleaner element
    • No air leakage from intake air system
    • No restriction of intake air system
    • Proper sealing of intake manifold and components attached to intake manifold
    • EGR valve
    • Ignition wiring
    • Fuel quality: proper octane, contamination, winter/summer blend
    • Electrical connections
    • Smooth operation of throttle valve
  • Are all items normal?
Yes Go to the next step.
No Repair or replace the malfunctioning part according to the inspection results.
Repeat Step 1.
2 INSPECT APP SENSOR SIGNAL 
  • Access the PCM PIDs APP1 and APP2 using the M-MDS.

    (See ON-BOARD DIAGNOSTIC TEST .)

  • Crank the engine with the accelerator pedal released.
  • Are the APP1 and APP2 PIDs indicating that the accelerator pedal is in the released position?
Yes Go to the next step.
No Inspect the following:
  • APP sensor terminal A-PCM terminal 1W
  • APP sensor terminal B-PCM terminal 1AP
  • APP sensor terminal C-PCM terminal 1AV
  • APP sensor terminal D-PCM terminal 1AS
  • APP sensor terminal E-PCM terminal 1AO
  • APP sensor terminal F-PCM terminal 1AL

Repair or replace the malfunctioning part according to the inspection results.
3 INSPECT TP SENSOR SIGNAL 
  • Access the PCM PID TP REL using the M-MDS.

    (See ON-BOARD DIAGNOSTIC TEST .)

  • Crank the engine with the accelerator pedal released.
  • Is the TP REL PID indicating that the accelerator pedal is in the released position?
Yes Go to the next step.
No Inspect the following:
  • TP sensor terminal A-PCM terminal 2AK
  • TP sensor terminal B-PCM terminal 2AO
  • TP sensor terminal C-PCM terminal 2AL
  • TP sensor terminal D-PCM terminal 2AP

Repair or replace the malfunctioning part according to the inspection results.
4 VERIFY PRESENT MALFUNCTION DTC 
  • Retrieve any continuous memory, KOEO and KOER DTCs using the M-MDS.

    (See ON-BOARD DIAGNOSTIC TEST .)

    (See KOEO/KOER SELF TEST .)

  • If the engine stalls, retrieve the continuous memory and KOEO DTCs.
  • Are there any DTCs displayed?
Yes DTC is displayed:
  • Go to the appropriate DTC inspection.

    (See DTC TABLE .)

    Communication error message is displayed:

  • Inspect the following:
  • Open circuit in the wiring harness between main relay terminal B and PCM terminal 1Q
  • Open circuit in the wiring harness between main relay terminal D and PCM terminal 1A, 1B
  • Main relay is stuck open.
  • Open or short circuit in the wiring harness between DLC-2 and PCM terminals 1AM or 1AI
  • Open or poor ground circuit (PCM terminal 1E, 1F, 1G, 1BE, or 1BF)
  • Poor connection of vehicle body ground

Repair or replace the malfunctioning part according to the inspection results.
No Go to the next step.
5 DETERMINE IF MALFUNCTION CAUSE IS DRIVE-BY-WIRE CONTROL SYSTEM OR OTHER 
  • Attempt to start the engine at part throttle.
  • Does the engine run smoothly at part throttle.
Yes Inspect the drive-by-wire control system operation. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION .)
Repair or replace the malfunctioning part according to the inspection results.
No Go to the next step.
6 DETERMINE IF MALFUNCTION CAUSE IS CKP SENSOR WIRING HARNESS OR OTHER 
  • Access the PCM PID RPM using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST .)
  • Is the RPM PID indicating the engine speed during engine cranking?
Yes Go to the next step.
No Inspect the following:
  • Open or short circuit in CKP sensor
  • Open or short circuit between CKP sensor terminal A and ground
  • Open or short circuit between CKP sensor terminal B and PCM terminal 2W
  • Open or short circuit between CKP sensor terminal C and PCM terminal 2AQ

Repair or replace the malfunctioning part according to the inspection results.
  • If the CKP sensor and wiring harness are normal, go to the next step.
7 VISUALLY INSPECT CKP SENSOR AND PULSE WHEEL 
  • Visually inspect the CKP sensor and teeth of the crankshaft pulley.
  • Are the CKP sensor and teeth of the crankshaft pulley normal?
Yes Go to the next step.
No Repair or replace the malfunctioning part according to the inspection results.
8 INSPECT IGNITION SYSTEM RELATED WIRING HARNESS 
  • 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 or replace suspected wiring harness and connector.
9 INSPECT IGNITION SYSTEM OPERATION  Yes Go to the next step.
  • If a symptom occurs with the A/C on, go to Step 15.
No Repair of replace the malfunctioning part according to the inspection results.
10 VERIFY SPARK PLUG CONDITION 
  • Verify the spark plug conditions when the spark plug removed in Step 9.

    (See SPARK PLUG INSPECTION .)

  • Is spark plug wet, covered with carbon or grayish white?
Yes Spark plug is wet or covered with carbon:
  • Inspect for fuel leakage from fuel injector.

Spark plug is grayish white:
  • Inspect the fuel injector for clogging.

Repair or replace the malfunctioning part according to the inspection results.
No Install the spark plugs on original cylinders.
Go to the next step.
11 INSPECT DEFORMED IN EXHAUST SYSTEM 
  • Visually inspect the exhaust system part.
  • Is there any deformed exhaust system part?
Yes Repair or replace the malfunctioning part according to the inspection results.
No Go to the next step.
12 INSPECT FUEL LINE PRESSURE  Yes Go to the next step.
No Zero or low:
  • Inspect the following:
  • Fuel pump relay
  • Fuel pump circuit
  • Fuel line for clogging
  • If there is no malfunction, replace the fuel pump unit.

(See FUEL PUMP UNIT REMOVAL/INSTALLATION .)
High:
  • Replace the fuel pump unit.

(See FUEL PUMP UNIT REMOVAL/INSTALLATION .)
13 INSPECT FUEL SYSTEM FOR FUEL LEAKAGE 
  • Visually inspect for fuel leakage at the fuel injector O-ring and fuel line.
  • Service if necessary.
  • Is the fuel line pressure held after ignition is off?

(See FUEL LINE PRESSURE INSPECTOR .)
Yes Go to the next step.
No Inspect the fuel injector.
(See FUEL INJECTOR INSPECTION .)
  • If the fuel injector is normal, replace the fuel pump unit.

(See FUEL PUMP UNIT REMOVAL/INSTALLATION .)
14 DETERMINE IF MALFUNCTION CAUSE IS A/C SYSTEM OR OTHER 
NOTE:
  • The following test is for stall concerns with the A/C on. If other symptoms exist, go to the next step.
  • Connect the pressure gauges to the A/C low side and high side pressure lines.
  • Turn the A/C on and 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 the 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 .)
For other symptoms:
  • Inspect the following:
    • Refrigerant charging amount
    • Cooling fan operation
  • Repair or replace the malfunctioning part according to the inspection results.
15 DETERMINE IF MALFUNCTION CAUSE IS EVAP CONTROL SYSTEM OR OTHER 
  • Disconnect the vacuum hose between purge solenoid valve and intake manifold from the purge solenoid valve side.
  • Plug the open end of the vacuum hose.
  • Start the engine.
  • Is the engine stall now eliminated?
Yes Inspect the following:
  • If the purge solenoid valve is stuck open.
  • EVAP control system

Repair or replace the malfunctioning part according to the inspection results.
No Go to the next step.
16 INSPECT INTAKE AIR SYSTEM FOR AIR LEAKAGE 
  • Is air leakage felt or heard at the intake air system components while racing the engine to higher speed?
Yes Repair or replace the malfunctioning part according to the inspection results.
No Go to the next step.
17 INSPECT EGR VALVE FOR STUCK 
  • 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 .)
No Go to the next step.
18 INSPECT VARIABLE VALVE TIMING CONTROL SYSTEM OPERATION  Yes Go to the next step.
No Repair or replace the malfunctioning part according to the inspection results.
19 INSPECT ENGINE COMPRESSION 
  • Is the engine compression correct?

(See COMPRESSION INSPECTION .)
Yes Go to the next step.
No Inspect for cause. Repair or replace the malfunctioning part according to the inspection results.
20 INSPECT IF MALFUNCTION CAUSE IS PCV VALVE OR VALVE TIMING  Yes Inspect the valve timing.
Repair or replace the malfunctioning part according to the inspection results.
No Replace the PCV valve and the oil separator as a single unit, then go to the next step.
(See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION .)
21
  • Verify test results.
  • If normal, return to diagnostic index to service any additional symptoms.

    (See SYMPTOM DIAGNOSTIC INDEX .)

  • If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis.
  • If vehicle is repaired, troubleshooting completed.
  • If vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.