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No. 12 Lack/Loss Of Power-Acceleration/Cruise: Contents

12 LACK/LOSS OF POWER-ACCELERATION/CRUISE
DESCRIPTION
  • Performance is poor under load. (e.g., power down when climbing hills)
TROUBLE AREA
  • Engine overheating
  • Drive-by-wire control system operates with brake override system
  • ECM DTC is stored
  • 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 VSV malfunction
  • Erratic signal to ECM
    • APP sensor or related circuit malfunction
    • Neutral switch or related circuit malfunction (MTX)
    • Communication error between TCM and ECM (ATX)
    • 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
    • Improper air/fuel mixture ratio control operation
    • Intermittent open or short circuit MAF sensor, APP sensor, TP sensor
  • Fuel leakage
  • Poor fuel quality
  • Air leakage or restriction in intake-air system
  • Air cleaner restricted or dirty
  • Vacuum leakage
  • Clutch slippage (MTX)
  • Brake dragging
  • Tire air pressure malfunction
  • Erratic or no signal from CMP sensor
    • Loose installation
    • Damaged trigger wheel
    • Open or short circuit in related wiring harness
  • Erratic signal from CKP sensor
    • Loose installation
    • Damaged trigger wheel (crankshaft pulley)
    • 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 ECM 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
    • Fuel filter clogged (built-into fuel pump unit)
    • Fuel pump mechanical malfunction
  • Throttle valve clogged
  • Low engine compression
  • Improper intake valve timing
  • Improper operation of hydraulic variable valve timing control system
  • Spark plug malfunction
  • Incorrect signal to ignition coil
  • Exhaust system and/or TWC restriction
  • PCV valve malfunction
  • Injector driver (built-into ECM) malfunction
  • ATX internal malfunction (ATX)
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 line spills and leakage are dangerous. Fuel can ignite and cause serious injury or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this information.

    Refer to PRECAUTION [07/2015 - ]

    Refer to ON-VEHICLE INSPECTION [07/2015 - ]

NOTE:
  • 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 matter.
NOTE:
  • Verify the malfunction symptom according to not only the PID value but also the symptom troubleshooting.
RELATED PIDS

Item (definition) Unit/Condition Definition Condition/Specification (Reference)
Accelerator pedal position sensor 1 % Accelerator pedal opening angle (absolute value) input from APP sensor No. 1
  • Accelerator pedal released: Approx. 16%
  • Accelerator pedal fully depressed: Approx. 91%
V APP sensor No. 1 voltage
  • Accelerator pedal released: Approx. 0.78 V
  • Accelerator pedal fully depressed: Approx. 4.54 V
Accelerator pedal position sensor 2 % Accelerator pedal opening angle (absolute value) input from APP sensor No. 2
  • Accelerator pedal released: Approx. 7.84%
  • Accelerator pedal fully depressed: Approx. 45.49%
V APP sensor No. 2 voltage
  • Accelerator pedal released: Approx. 0.39 V
  • Accelerator pedal fully depressed: Approx. 2.27 V
Clutch Pedal Position Switch/Neutral Switch Circuit (MTX) False/True Shift lever position
  • Other than neutral: False
  • Neutral: True
Engine coolant temperature °C, °F Engine coolant temperature
  • Displays ECT
V ECT sensor No. 1 voltage Ignition switched ON (engine off)
  • ECT is 29°C {84°F}: Approx. 2.65 V
  • ECT is 88°C {190°F}: Approx. 0.71 V
Fuel pressure sensor kPa Fuel pressure
  • Displays fuel pressure
V Fuel pressure sensor voltage Ignition switched ON (engine off)
  • Fuel pressure is approx. 16.91 MPa {172.4 kgf/cm2 , 2453 psi}: Approx. 2.91 V

Idle (after warm up)
  • Fuel pressure is 3.44-3.95 MPa {35.1-40.2 kgf/cm2 , 499-572 psi}: 0.98-1.05 V (ECT is 90°C {194°F})
Intake Air Temperature °C, °F Intake air temperature (No. 1)
  • Displays IAT (No. 1)
V IAT sensor No. 1 voltage
  • IAT is 20°C {68°F}: Approx. 2.70 V
  • IAT is 40°C {104°F}: Approx. 1.80 V
  • IAT is 60°C {140°F}: Approx. 1.20 V
Engine load % Ratio of actual amount of intake air to the maximum air charging amount (mass volume) of cylinder
  • Idle (after warm up): Approx. 17.64%
  • Racing (engine speed is 2000 RPM): Approx. 14.51%
  • Racing (engine speed is 4000 RPM): Approx. 21.17%
Long term fuel trim 1 % Fuel learning correction amount estimated based on A/F sensor signal
  • Idle (after warm up): Approx. -2.34%
  • Racing (engine speed is 2000 RPM): Approx. -0.78%
  • Racing (engine speed is 4000 RPM): Approx. -0.78%
Mass Air Flow gm/sec Mass air flow
  • Displays MAF
V MAF sensor voltage
  • Ignition switched ON (engine off) (MAF: 0.59 g/s {0.078 lb/min}): Approx. 0.72 V
  • Idle (after warm up) (MAF: 2.17 g/s {0.287 lb/min}): Approx. 0.97 V
  • Racing (engine speed is 2000 RPM) (MAF: 4.73 g/s {0.626 lb/min}): Approx. 1.26 V
Manifold absolute pressure sensor kPa Manifold absolute pressure
  • Displays MAP
V MAP sensor voltage
  • Ignition switched ON (engine off) (MAP:101 kPa {1.03 kgf/cm2 , 14.6 psi}): Approx. 4.12 V
  • Idle (after warm up) (MAP: 33 kPa {0.34 kgf/cm2 , 4.8 psi}): Approx. 1.9 V
  • Racing (engine speed is 2000 RPM) (MAP: 26 kPa {0.27 kgf/cm2 , 3.8 psi}): Approx. 1.23 V
Heated Exhaust Gas Oxygen Sensor (bank 1, sensor 1) μA A/F sensor current
  • Idle (after warm up): Approx. 0-50 μA
  • Deceleration fuel cut (accelerator pedal released from engine speed of 4000 RPM or more): Approx. 3.84 mA
Heated Exhaust Gas Oxygen Sensor (bank 1, sensor 2) V HO2S voltage
  • Idle (after warm up): 0-1.0 V
  • Deceleration fuel cut (accelerator pedal released from engine speed of 4000 RPM or more): Approx. 0 V
Engine Revolutions Per Minute RPM Engine speed
  • Displays engine speed
Short term fuel trim 1 % Fuel feedback correction amount estimated based on A/F sensor signal
  • Idle (after warm up): Approx. 0%
  • Racing (engine speed is 2000 RPM): Approx. 1.56%
  • Racing (engine speed is 4000 RPM): Approx. 4.68%
Relative Throttle Position % Throttle valve opening angle (relative value) with value at throttle valve fully open timing as the start point
  • Accelerator pedal released: Approx. 12%
  • Accelerator pedal fully depressed: Approx. 82%
Vehicle Speed km/h Vehicle speed
  • Displays vehicle speed
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