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Home >> Mazda >> 2021 >> 3 Base >> Repair and Diagnosis >> Engine Performance >> System >> Symptom Troubleshooting - Engine (VINS 7, L, M) >> Emission Compliance >> Notes

Emission Compliance: Notes

EMISSION COMPLIANCE (VINs 7, L, M), US) DESCRIPTION AND POSSIBLE CAUSE

Troubleshooting item Emission compliance
Description
  • Fails emissions test.
Possible cause
  • Engine overheating
  • Cooling system malfunction
  • PCM DTC is stored
  • Incorrect fuel injection timing
  • Incorrect ignition timing
  • Spark plug malfunction
  • Ignition coil malfunction
  • CMP sensor malfunction
  • CKP sensor malfunction
  • Purge solenoid valve malfunction
  • Inadequate fuel pressure
  • Fuel leakage at the fuel line and/or fuel injector
  • Fuel pressure sensor or related circuit malfunction
  • High pressure fuel pump malfunction
  • Spill valve control solenoid valve control circuit malfunction (damage to driver in PCM caused by short circuit to ground system)
  • Spill valve control solenoid valve malfunction (built-into high pressure fuel pump)
  • Relief valve (built-into high pressure fuel pump) malfunction
  • Fuel line restriction
  • Fuel pump unit malfunction
  • Air leakage from intake-air system
  • Vacuum lines leakage or blockage
  • Charcoal canister main damage (U. S. A. and CANADA)
  • Charcoal canister sub damage (U. S. A. and CANADA)
  • Charcoal canister damage (Except (U. S. A. and CANADA))
  • Improper engine coolant level
  • Excessive carbon built-up in combustion chamber
  • Improper engine compression
  • Improper intake valve timing
  • Improper exhaust valve timing
  • Exhaust system and/or TWC restriction
  • Exhaust gas leakage from exhaust system
  • TWC malfunction (PCM DTC is stored.)
  • Positive crankcase ventilation system malfunction
  • PCV valve malfunction or incorrect valve installation
  • Clogging in positive crankcase ventilation system hoses (PCV valve hose, ventilation hose)
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 may cause irritation if it comes in contact with skin and eyes.
  • If fuel ignites and causes a fire, it may lead to serious injury or death, and damage to property and facilities.
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.
System wiring diagram
  • Not applicable
Connector diagram
  • Not applicable