NO.12 LACK/LOSS OF POWER-ACCELERATION/CRUISE [SKYACTIV-G 2.5]

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2014 - Mazda6 - Engine

NO.12 LACK/LOSS OF POWER-ACCELERATION/CRUISE [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 pump mechanical malfunction Improper operation of electric variable valve timing control system (PCM DTC is stored.) Improper operation of hydraulic variable valve timing control system Throttle valve clogged Low engine compression Improper intake valve timing due to timing chain jumping Improper exhaust valve timing due to timing chain jumping 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)
POSSIBLE CAUSE	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 [SKYACTIV-G 2.5].) (See AFTER SERVICE PRECAUTION [SKYACTIV-G 2.5].) 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	%	APP sensor No.1	Accelerator pedal released: Approx. 15% Accelerator pedal depressed: Approx. 82%
APP1	V	APP sensor No.1	Accelerator pedal released: Approx. 0.75 V Accelerator pedal depressed: Approx. 4.1 V
APP2	%	APP sensor No.2	Accelerator pedal released: Approx. 7.45% Accelerator pedal depressed: Approx. 41%
APP2	V	APP sensor No.2	Accelerator pedal released: Approx. 0.38 V Accelerator pedal 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 (No.1)	Displays ECT
ECT	V	Engine coolant temperature (No.1)	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	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	Intake air temperature (No.1)	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	%	Engine load	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	%	Long term fuel trim	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	Mass air flow	Switch ignition 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	Manifold absolute pressure	Switch ignition 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	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	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	%	Short term fuel trim	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 position signal (relative value)	Accelerator pedal released: Approx. 12% Accelerator pedal depressed: Approx. 82%
VSS	KPH, MPH	Vehicle speed	Displays vehicle speed

Diagnostic Procedure


STEP	INSPECTION	RESULTS	ACTION
1	VERIFY IF MALFUNCTION INCLUDES ROUGH IDLING Does the engine idle rough?	Yes	Perform the symptom troubleshooting “NO.8 ENGINE RUNS ROUGH/ROLLING IDLE”. (See NO.8 ENGINE RUNS ROUGH/ROLLING IDLE [SKYACTIV-G 2.5].)
1		No	Go to the next step.
2	VERIFY IF MALFUNCTION CAUSE IS OVERHEATING Is the engine overheating?	Yes	Perform the symptom troubleshooting “NO.17 COOLING SYSTEM CONCERNS-OVERHEATING”. (See NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [SKYACTIV-G 2.5].)
2		No	Go to the next step.
3	VERIFY DRIVE-BY-WIRE CONTROL SYSTEM OPERATES WITH BRAKE OVERRIDE SYSTEM Retrieve the PCM DTC using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [SKYACTIV-G 2.5].) Is the DTC P2299:00 present?	Yes	Go to the applicable DTC inspection. (drive-by-wire control system operates with brake override system.) (See DTC P2299:00 [SKYACTIV-G 2.5].)
3		No	Go to the next step.
4	VERIFY PCM DTC Retrieve any DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [SKYACTIV-G 2.5].) Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [SKYACTIV-G 2.5].)
4		No	Go to the next step.
5	VERIFY CURRENT INPUT SIGNAL STATUS CAUTION: While performing this step, always operate the vehicle in a safe and lawful manner. When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later. Access the following PIDs using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST [SKYACTIV-G 2.5].) APP1 APP2 CPP/PNP (MTX) ECT FUEL_PRES IAT MAF MAP TP REL O2S11 O2S12 SHRTFT1 LONGFT1 Do the PIDs indicate the correct values under the malfunction condition? (See PCM INSPECTION [SKYACTIV-G 2.5].)	Yes	Go to the next step.
5		No	APP1, APP2 PIDs are not as specified: Inspect the APP sensor. (See ACCELERATOR PEDAL POSITION (APP) SENSOR INSPECTION [SKYACTIV-G 2.5].) CPP/PNP PID is not as specified: (MTX) Inspect the neutral switch. (See NEUTRAL SWITCH INSPECTION [SKYACTIV-G 2.5].) ECT PID is not as specified: Inspect the ECT sensor No.1. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION [SKYACTIV-G 2.5].) FUEL_PRES PID is not as specified: Inspect the fuel pressure sensor. (See FUEL PRESSURE SENSOR INSPECTION [SKYACTIV-G 2.5].) IAT PID is not as specified: Inspect the IAT sensor No.1. (See INTAKE AIR TEMPERATURE (IAT) SENSOR INSPECTION [SKYACTIV-G 2.5].) MAF PID is not as specified: Inspect the MAF sensor. (See MASS AIR FLOW (MAF) SENSOR INSPECTION [SKYACTIV-G 2.5].) MAP PID is not as specified: Inspect the MAP sensor. (See MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR INSPECTION [SKYACTIV-G 2.5].) TP REL PID is not as specified: Inspect the TP sensor. (See THROTTLE POSITION (TP) SENSOR INSPECTION [SKYACTIV-G 2.5].) O2S11, SHRTFT1, LONGFT1 PIDs are not as specified: Inspect the A/F sensor. (See AIR FUEL RATIO (A/F) SENSOR INSPECTION [SKYACTIV-G 2.5].) O2S12 PID is not as specified: Inspect the HO2S. (See HEATED OXYGEN SENSOR (HO2S) INSPECTION [SKYACTIV-G 2.5].) Repair or replace the malfunctioning part according to the inspection results. If the malfunction remains: Inspect communication error between TCM and PCM. (ATX) Repair or replace the malfunctioning part according to the inspection results if necessary. Perform the “INTERMITTENT CONCERN TROUBLESHOOTING” procedure. (See INTERMITTENT CONCERN TROUBLESHOOTING [SKYACTIV-G 2.5].)
6	INSPECT A/C CUT-OFF CONTROL SYSTEM OPERATION Perform the A/C Cut-off Control System Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [SKYACTIV-G 2.5].) Does the A/C cut-off operation work properly?	Yes	Go to the next step.
6		No	Repair or replace the malfunctioning part according to the inspection results.
7	INSPECT DRIVE-BY-WIRE CONTROL SYSTEM OPERATION Perform the TP sweep inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [SKYACTIV-G 2.5].) Does the drive-by-wire control system work properly?	Yes	Go to the next step.
7		No	Repair or replace the malfunctioning part according to the inspection results.
8	INSPECT FUEL INJECTOR OPERATION Perform the Fuel Injector Operation Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [SKYACTIV-G 2.5].) Do the fuel injectors operate properly?	Yes	Go to the next step.
8		No	Repair or replace the malfunctioning part according to the inspection results.
9	INSPECT PURGE CONTROL SYSTEM OPERATION Perform the Purge Control System Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [SKYACTIV-G 2.5].) Does the purge solenoid valve work properly?	Yes	Go to the next step.
9		No	Repair or replace the malfunctioning part according to the inspection results.
10	INSPECT FUEL SYSTEM FOR FUEL LEAKAGE Inspect for fuel leakage in the fuel line. Is there any leakage?	Yes	Repair or replace the malfunctioning part according to the inspection results.
10		No	Go to the next step.
11	INSPECT RELATED PART CONDITION Inspect the following: Fuel quality (proper octane, contamination, winter/summer blend) Air leakage or restriction in intake-air system Air cleaner restricted or dirty Vacuum leakage Clutch slippage (MTX) Brake dragging Tire air pressure CKP sensor, intake CMP sensor and exhaust CMP sensor Installation condition (See CRANKSHAFT POSITION (CKP) SENSOR REMOVAL/INSTALLATION [SKYACTIV-G 2.5].) (See CAMSHAFT POSITION (CMP) SENSOR REMOVAL/INSTALLATION [SKYACTIV-G 2.5].) Damaged trigger wheel, intake camshaft and exhaust camshaft Is there any malfunction?	Yes	Service if necessary. Repeat this step.
11		No	Go to the next step.
12	INSPECT FUEL PRESSURE (HIGH-SIDE) Start the engine and warm it up completely. Access the FUEL_PRES PID using the M-MDS at idle. (See ON-BOARD DIAGNOSTIC TEST [SKYACTIV-G 2.5].) Is the FUEL_PRES PID value approx. 3 MPa {31 kgf/cm², 435 psi}?	Yes	Go to Step 14.
12		No	Lower than 3 MPa {31 kgf/cm², 435 psi}: Inspect the following: Fuel leakage at the fuel line and fuel injector Fuel pump Perform the Fuel Pump (Low-pressure Side) Operation Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [SKYACTIV-G 2.5].) Fuel pressure sensor (See FUEL PRESSURE SENSOR INSPECTION [SKYACTIV-G 2.5].) High pressure fuel pump (See HIGH PRESSURE FUEL PUMP INSPECTION [SKYACTIV-G 2.5].) If there is any malfunction: Repair or replace the malfunctioning part according to the inspection results. If there is no malfunction: Go to the next step. Higher than 3 MPa {31 kgf/cm², 435 psi}: Go to the next step.
13	INSPECT SPILL VALVE CONTROL SOLENOID VALVE CONTROL CIRCUIT FOR SHORT TO GROUND Switch the ignition off. Disconnect the high pressure fuel pump and PCM connectors. Inspect for continuity between high pressure fuel pump terminal A (wiring harness-side) and body ground. Is there continuity?	Yes	Refer to the wiring diagram and verify whether or not there is a common connector between high pressure fuel pump terminal A and PCM terminal 1EE. If there is a common connector: Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to ground. Repair or replace the malfunctioning part. If there is no common connector: Repair or replace the wiring harness which has a short to ground. If the malfunction remains: Replace the PCM. (damage to driver in PCM) (See PCM REMOVAL/INSTALLATION [SKYACTIV-G 2.5].)
13		No	Replace the high pressure fuel pump. (See HIGH PRESSURE FUEL PUMP REMOVAL/INSTALLATION [SKYACTIV-G 2.5].)
14	INSPECT FUEL PRESSURE (LOW-SIDE) Connect the fuel pressure gauge between fuel pump and high pressure fuel pump. Measure the low side fuel pressure. (See FUEL LINE PRESSURE INSPECTION [SKYACTIV-G 2.5].) Is the low side fuel pressure within specification? Specification: 405—485 kPa {4.13—4.94 kgf/cm², 58.8—70.3 psi}	Yes	Go to the next step.
14		No	Inspect the following: Fuel line restriction Fuel filter clogged If there is any malfunction: Repair or replace the malfunctioning part according to the inspection results. If there is no malfunction: Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [SKYACTIV-G 2.5].)
15	INSPECT HYDRAULIC VARIABLE VALVE TIMING CONTROL SYSTEM OPERATION Perform the Hydraulic Variable Valve Timing Control System Operation Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [SKYACTIV-G 2.5].) Does the hydraulic variable valve timing control system work properly?	Yes	Go to the next step.
15		No	Repair or replace the malfunctioning part according to the inspection results.
16	INSPECT THROTTLE BODY FOR CLOGGING Visually inspect the throttle valve. (See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION [SKYACTIV-G 2.5].) Is any foreign matter adhering around the throttle valve?	Yes	Clean the throttle valve.
16		No	Go to the next step.
17	INSPECT ENGINE COMPRESSION Measure the compression pressure for each cylinder. (See COMPRESSION INSPECTION [SKYACTIV-G 2.5].) Are compression pressures within specification? Specification: Compression Standard: 954 kPa {9.73 kgf/cm², 138 psi} (300 rpm) Minimum: 763 kPa {7.78 kgf/cm², 111 psi} (300 rpm) Maximum difference between cylinders: 161 kPa {1.64 kgf/cm², 23.4 psi} (300 rpm) NOTE: Because the SKYACTIV-G 2.5 retards the intake valve closing timing, compression pressure is low.	Yes	Go to the next step.
17		No	Inspect the following: Damaged valve seat Worn valve stem and valve guide Worn or stuck piston ring Worn piston, piston ring or cylinder Improper intake valve timing Improper exhaust valve timing Service if necessary.
18	VERIFY SPARK PLUG CONDITION Inspect the spark plug condition. (See SPARK PLUG INSPECTION [SKYACTIV-G 2.5].) Is the spark plug wet, covered with carbon or grayish white?	Yes	Spark plug is wet or covered with carbon: Perform the Spark Test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [SKYACTIV-G 2.5].) Repair or replace the malfunctioning part according to the inspection results. Spark plug is grayish white: Inspect the fuel injector for restriction. Repair or replace the malfunctioning part according to the inspection results.
18		No	Go to the next step.
19	INSPECT EXHAUST SYSTEM FOR RESTRICTION Inspect for restriction in the exhaust system and the TWC. Is there any restriction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
19		No	Go to the next step.
20	INSPECT IF MALFUNCTION CAUSE IS PCV VALVE OR INJECTOR DRIVER (PCM INTEGRATED) Inspect the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [SKYACTIV-G 2.5].) Is there any malfunction?	Yes	Replace the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [SKYACTIV-G 2.5].)
20		No	Injector driver malfunction. Replace the PCM. (See PCM REMOVAL/INSTALLATION [SKYACTIV-G 2.5].) If the problem remains, overhaul the engine.
21	Verify the test results. If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [SKYACTIV-G 2.5].) If the malfunction remains, inspect the related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If the vehicle is repaired, troubleshooting is completed. If the vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.

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