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Home >> Mazda >> 2012 >> 6 i Touring >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 7 (Symptom Troubleshooting [Engine Control System - MZI 3.7 V6]) >> No. 26 Exhaust Sulphur Smell >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different variant/trim than selected.
STEP INSPECTION RESULTS ACTION
1 VERIFY IF THERE IS DRIVEABILITY MALFUNCTION OR EXHAUST GAS MALFUNCTION 
  • Are any driveability or exhaust smoke concerns present?
Yes Go to the appropriate symptom troubleshooting.
No Go to the next step.
2 INSPECT RELATED PART CONDITION 
  • Inspect the following:
    • Electrical connections
    • Vacuum lines
    • Fuel quality
  • Are all items normal?
Yes Go to the next step.
No Repair or replace the malfunctioning part according to the inspection results.
Repeat Step 2.
3 VERIFY PCM DTC 
  • Switch the ignition to ON (Engine off).
  • Retrieve any DTCs using the M-MDS.

    (See ON-BOARD DIAGNOSTIC TEST .)

  • Are there any DTCs displayed?
Yes DTC is displayed:
  • Go to the appropriate DTC inspection.

    (See DTC TABLE .)

No No DTC is displayed:
  • Go to the next step.
4 INSPECT FUEL LINE PRESSURE 
  • Install the fuel pressure gauge between the fuel pipe and fuel distributor.
  • Start the engine and idle it.
  • Measure the fuel line pressure during idle.

    (See FUEL LINE PRESSURE INSPECTION .)

  • Is the fuel line pressure correct during idle?
Yes Go to the next step.
No Zero or low:
  • Inspect for the following:
    • Fuel pump relay
    • Fuel pump circuit
    • Fuel line for clogging

High:
5 DETERMINE IF MALFUNCTION CAUSE IS CHARCOAL CANISTER OR FUEL TANK VENT SYSTEM 
  • Inspect the charcoal canister for fuel saturation.
  • Is excess amount of liquid fuel present in canister?
Yes Replace the charcoal canister.
(See CHARCOAL CANISTER, CANISTER VENT (CV) SOLENOID VALVE, AIR FILTER COMPONENT REMOVAL/INSTALLATION .)
No Inspect the fuel tank vent system.
Repair or replace the malfunctioning part according to the inspection results.
  • If the fuel tank vent system is normal, suggest trying a different brand since sulphur content can vary in different fuels.
6 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.