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Home >> Mazda >> 2021 >> CX-9 Signature >> Repair and Diagnosis >> Engine Performance >> System >> Symptom Troubleshooting - Engine >> No. 12 Lack/Loss Of Power-Acceleration/Cruise >> Notes
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No. 12 Lack/Loss Of Power-Acceleration/Cruise: Notes

NO. 12 LACK/LOSS OF POWER-ACCELERATION/CRUISE (SKYACTIV-G 2.5T) DESCRIPTION AND POSSIBLE CAUSE

12 LACK/LOSS OF POWER-ACCELERATION/CRUISE
DESCRIPTION
  • Performance is poor under load. (e.g., power down when climbing hills)
POSSIBLE CAUSE
  • Engine overheating
  • The engine torque control is activated when the engine coolant temperature is high
  • Drive-by-wire control system operates with brake override system
  • PCM DTC is stored
  • Erratic signal to PCM
    • APP sensor or related circuit malfunction
    • Communication error between TCM and PCM
    • ECT sensor No. 1 or related circuit malfunction
    • Fuel pressure sensor or related circuit malfunction
    • IAT sensor No. 1 (integrated in MAF sensor/IAT sensor No. 1) or related circuit malfunction
    • MAF sensor or related circuit malfunction
    • MAP sensor or related circuit malfunction
    • A/F sensor or related circuit malfunction
    • HO2S or related circuit malfunction
    • Boost air temperature sensor or related circuit malfunction
    • Boost pressure sensor or related circuit malfunction
    • Improper air/fuel mixture ratio control operation
      • Intermittent open or short circuit MAF sensor, APP sensor, TP sensor
  • Improper operation of A/C system
  • Improper operation of drive-by-wire control system
  • Throttle body malfunction
  • Incorrect fuel injection timing
  • Fuel injector malfunction
  • Purge solenoid valve malfunction
  • Fuel leakage
  • Poor fuel quality
  • Air leakage or restriction in intake-air system
  • Vacuum leakage
  • Air cleaner restricted or dirty
  • Charge air cooler malfunction
  • Brake dragging
  • Tire air pressure malfunction
  • Erratic signal from CKP sensor
    • Loose installation
    • Damaged trigger wheel (crankshaft pulley)
      • Open or short circuit in related wiring harness
  • Erratic or no signal from CMP sensor
    • Loose installation
    • Damaged trigger wheel (intake camshaft)
    • Damaged trigger wheel (exhaust camshaft)
      • Open or short circuit in related wiring harness
  • Inadequate fuel pressure (high or low pressure side)
    • Fuel pressure sensor 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 (built-into high pressure fuel pump) malfunction
    • Relief valve (built-into high pressure fuel pump) malfunction
    • Fuel line restricted or clogged
    • Fuel filter clogged (built-into fuel pump unit)
    • Fuel pump mechanical malfunction
      • Fuel pump control module malfunction
  • Throttle valve restricted or clogged
  • Low engine compression
  • Improper intake valve timing
  • Improper exhaust valve timing
  • Wastegate control system malfunction
    • Wastegate valve stuck open
    • Wastegate valve position sensor malfunction
      • Wastegate valve actuator malfunction
  • Improper operation of electric variable valve timing control system
    • Electric variable valve timing driver malfunction
    • Electric variable valve timing motor malfunction
      • Electric variable valve timing actuator malfunction
  • Improper operation of hydraulic variable valve timing control system
  • Spark plug malfunction
  • Ignition coil malfunction
  • Exhaust system and/or TWC restriction
  • PCV valve malfunction
  • EGR valve stuck open
  • Three way solenoid valve stuck open
  • Turbocharger malfunction
  • Injector driver (built-into PCM) malfunction
  • ATX internal malfunction
    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.
      • Highly pressurized fuel may spray out if the fuel line is cut. Due to the following dangers occurring with a fuel spray, always complete the "Fuel Line Safety Procedure" to prevent the fuel from spraying. (See BEFORE SERVICE PRECAUTION [SKYACTIV-G 2.5T] .)
  • 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.
      • Fuel is highly flammable and dangerous. Fuel line spills and leakage can cause serious injury or death, and damage to equipment. Always refer to the "Quick Release Connector Removal/Installation (fuel system)" before performing the fuel hose installation, and execute the "Fuel Leakage Inspection" after installation. (See QUICK RELEASE CONNECTOR REMOVAL/INSTALLATION [SKYACTIV-G 2.5T] .) (See AFTER SERVICE PRECAUTION [SKYACTIV-G 2.5T] .)
        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.