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

NO. 12 LACK/LOSS OF POWER-ACCELERATION/CRUISE DESCRIPTION AND POSSIBLE CAUSES (SKYACTIV-G 2.0, SKYACTIV-G 2.5)

12	LACK/LOSS OF POWER-ACCELERATION/CRUISE
DESCRIPTION	Performance is poor under load, (e.g., power down when climbing hills)
POSSIBLE CAUSE	Engine overheating Drive-by-wire control system operates with brake override system PCM 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 solenoid valve malfunction Erratic signal to PCM APP sensor or related circuit malfunction Neutral switch or related circuit malfunction (MTX) Communication error between TCM and PCM (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 (intake camshaft and/or exhaust camshaft) 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 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 Fuel filter clogged (built-into fuel pump unit) Fuel pump mechanical malfunction Throttle valve clogged Low engine compression Improper intake valve timing Improper exhaust valve timing 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 Incorrect signal to ignition coil Exhaust system and/or TWC restriction PCV valve malfunction Injector driver (built-into PCM) 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 manual. (See BEFORE SERVICE PRECAUTION .) (See AFTER SERVICE PRECAUTION .) 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 matter.

CAUTION:

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)
APP1	%	Accelerator pedal opening angle (absolute value) input from APP sensor No. 1	Accelerator pedal released: Approx. 15% Accelerator pedal fully depressed: Approx. 82%
APP1	V	APP sensor No. 1 voltage	Accelerator pedal released: Approx. 0.75 V Accelerator pedal fully depressed: Approx. 4.1 V
APP2	%	Accelerator pedal opening angle (absolute value) input from APP sensor No. 2	Accelerator pedal released: Approx. 7.45% Accelerator pedal fully depressed: Approx. 41%
APP2	V	APP sensor No. 2 voltage	Accelerator pedal released: Approx. 0.38 V Accelerator pedal fully depressed: Approx. 2.05 V
CPP/PNP (MTX)	Off/On	Shift lever position	Other than neutral: Off Neutral: On
ECT	°C, °F	Engine coolant temperature	Displays ECT
ECT	V	ECT sensor No. 1 voltage	ECT is 20 °C {68 °F}: Approx. 3.10 V ECT is 40 °C {104 °F}: Approx. 2.16 V ECT is 60 °C {140 °F}: Approx. 1.40 V ECT is 80 °C {176 °F}: Approx. 0.87 V ECT is 100 °C {212 °F}: Approx. 0.54 V
FUEL_PRES	KPa {MPa}, mBar {Bar}, psi, in H20	Fuel pressure	Displays fuel pressure
FUEL_PRES	V	Fuel pressure sensor voltage	Fuel pressure is 3.0 MPa {31 kgf/cm² , 435 psi}: Approx. 0.92 V Fuel pressure is 4.8 MPa {49 kgf/cm² , 696 psi}: Approx. 1.17 V
IAT	°C,°F	Intake air temperature (No. 1)	Displays IAT (No. 1)
IAT	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
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 2, 000 rpm): Approx. 14.51% Racing (engine speed is 4, 000 rpm): Approx. 21.17%
LONGFT1	%	Fuel learning correction amount estimated based on A/F sensor signal	Idle (after warm up): Approx. -2.34% Racing (engine speed is 2, 000 rpm): Approx. -0.78% Racing (engine speed is 4, 000 rpm): Approx. -0.78%
MAF	g/Sec	Mass air flow	Displays MAF
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. 0.86 V Racing (engine speed is 2, 000 rpm) (MAF: 4.73 g/s {0.626 lb/min}): Approx. 1.07 V
MAP	KPa {MPa}, mBar {Bar}, psi, in H20	Manifold absolute pressure	Displays MAP
MAP	V	MAP sensor voltage	Ignition switched ON (engine off) (MAP: 101 kPa {1.03 kgf/cm² , 14.6 psi}): Approx. 4.07 V Idle (after warm up) (MAP: 33 kPa {0.34 kgf/cm² , 4.8 psi}): Approx. 1.34 V Racing (engine speed is 2, 000 rpm) (MAP: 26 kPa {0.27 kgf/cm² , 3.8 psi}): Approx.1.05 V
O2S11	μA	A/F sensor current	Idle (after warm up): Approx. -39 μA Deceleration fuel cut (accelerator pedal released from engine speed of 4, 000 rpm or more): Approx. 3.84 mA
O2S12	V	HO2S voltage	Idle (after warm up): 0-1.0 V Deceleration fuel cut (accelerator pedal released from engine speed of 4, 000 rpm or more): Approx. 0 V
RPM	RPM	Engine speed	Displays engine speed
SHRTFT1	%	Fuel feedback correction amount estimated based on A/F sensor signal	Idle (after warm up): Approx. 1.56% Racing (engine speed is 2, 000 rpm): Approx. -3.12% Racing (engine speed is 4, 000 rpm): Approx. -8.59%
TP_REL	%	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%
VSS	KPH, MPH	Vehicle speed	Displays vehicle speed