Diagnostic Procedure

NO. 14 POOR FUEL ECONOMY (SKYACTIV-G 2.0, SKYACTIV-G 2.5) - DIAGNOSTIC PROCEDURE

STEP	INSPECTION	RESULTS	ACTION
1	VERIFY IF MALFUNCTION CAUSED BY ENGINE MALFUNCTION Verify the vehicle engine condition. Can malfunction symptoms other than "NO. 14 POOR FUEL ECONOMY" be verified?	Yes	Go to the applicable symptom troubleshooting. (See SYMPTOM DIAGNOSTIC INDEX .)
1		No	Go to the next step.
2	INSPECT COOLING SYSTEM FOR MALFUNCTION Is any cooling system concern (overheating, runs cold) present?	Yes	Perform the applicable symptom troubleshooting. (See NO. 17 COOLING SYSTEM CONCERNS-OVERHEATING .) (See NO. 18 COOLING SYSTEM CONCERNS-RUNS COLD .)
2		No	Go to the next step.
3	VERIFY PCM DTC Retrieve any DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST .) Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [PCM (SKYACTIV-G 2.0, SKYACTIV-G 2.5)] .)
3		No	Go to the next step.
4	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 .) APP1 APP2 ECT IAT MAF MAP TP_REL Do the PIDs indicate the correct values under the malfunction condition? (See PCM INSPECTION .)	Yes	Go to the next step.
4		No	APP1, APP2 PIDs are not as specified: Inspect the APP sensor. (See ACCELERATOR PEDAL POSITION (APP) SENSOR INSPECTION .) ECT PID is not as specified: Inspect the ECT sensor No. 1. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION .) IAT PID is not as specified: Inspect the IAT sensor No. 1. (See INTAKE AIR TEMPERATURE (IAT) SENSOR INSPECTION .) MAF PID is not as specified: Inspect the MAF sensor. (See MASS AIR FLOW (MAF) SENSOR INSPECTION .) MAP PID is not as specified: Inspect the MAP sensor. (See MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR INSPECTION .) TP_REL PID is not as specified: Inspect the TP sensor. (See THROTTLE POSITION (TP) SENSOR INSPECTION .) Repair or replace the malfunctioning part according to the inspection results. If the malfunction remains: Perform the "INTERMITTENT CONCERN TROUBLESHOOTING" procedure. (See INTERMITTENT CONCERN TROUBLESHOOTING .)
5	DETERMINE IF MALFUNCTION CAUSE IS A/C REQUEST SIGNAL OR OTHER Access the AC_REQ PID using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST .) Monitor the AC_REQ PID while turning on and off the air conditioner using the switch on the control panel. Does the AC_REQ PID value change from on to off according to switch control panel?	Yes	Go to the next step.
5		No	If the AC_REQ PID is always ON: Perform the symptom troubleshooting "NO. 24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY". (See NO. 24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY .) If the AC_REQ PID is always OFF: Perform the symptom troubleshooting "NO. 23 A/C DOES NOT WORK SUFFICIENTLY". (See NO. 23 A/C DOES NOT WORK SUFFICIENTLY .)
6	INSPECT FUEL INJECTOR OPERATION Perform the Fuel Injector Operation Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION .) Do the fuel injectors operate properly?	Yes	Go to the next step.
6		No	Repair or replace the malfunctioning part according to the inspection results.
7	INSPECT ENGINE.IG1 15 A FUSE Switch the ignition off. Remove the ENGINE.IG1 15 A fuse. Inspect the ENGINE.IG1 15 A fuse. Is there any malfunction?	Yes	If the fuse is blown: Refer to the wiring diagram and verify whether or not there is a common connector between ENGINE.IG1 15 A fuse and PCM terminal 2H. 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. Replace the fuse. If the fuse is damaged: Replace the fuse. Go to the next step.
7		No	Reinstall the ENGINE.IG1 15 A fuse, then go to the next step.
8	INSPECT IG1 RELAY CIRCUIT FOR SHORT TO POWER SUPPLY Remove the IG1 relay. Disconnect the PCM connector. Measure the voltage at the IG1 relay terminal C (wiring harness-side). Is the voltage 0 V?	Yes	Inspect the IG1 relay. (See RELAY INSPECTION .) If there is any malfunction: Replace the IG1 relay. If there is no malfunction: Reconnect all disconnected connectors. Go to the next step.
8		No	Refer to the wiring diagram and verify whether or not there is a common connector between IG1 relay terminal C and PCM terminal 2H. 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 power supply. Repair or replace the malfunctioning part. If there is no common connector: Repair or replace the wiring harness which has a short to power supply.
9	INSPECT RELATED PART CONDITION Inspect the following: Air cleaner element for contamination Intake-air system restriction Fuel quality (proper octane, contamination, winter/summer blend) Coolant level Clutch slippage (MTX) ATF level (ATX) Brake dragging Tire air pressure Vacuum leakage Fuel leakage MAF sensor contaminated Tires, wheels (large size) Change of intake air system components and exhaust system components Engine operation time is longer than traveled distance Vehicle is driven in congested traffic frequently Left idling for long periods Amount of fuel injection increases Overloaded Frequent acceleration/deceleration Frequently driving on ascending roads Travel distance per one drive is short (amount of time for warm-up is long during engine operation) Improper load signal input Discharge is high when the vehicle is not used Driver forgets to switch electronic device off Electronic device is frequently used with engine stopped (no power generation) Remote transmitter is left in vehicle with engine stopped (no power generation) (with advanced keyless entry system) Vehicle left undriven for long periods Large amount of parasitic draw (especially after-market electronic devices) CKP sensor, intake CMP sensor and exhaust CMP sensor Installation condition (See CRANKSHAFT POSITION (CKP) SENSOR REMOVAL/INSTALLATION .) (See CAMSHAFT POSITION (CMP) SENSOR REMOVAL/INSTALLATION .) Damaged trigger wheel, intake camshaft and exhaust camshaft Is there any malfunction?	Yes	Service if necessary. Repeat this step.
9		No	Go to the next step.
10	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 .) Is the FUEL_PRES PID value approx. 3 MPa {31 kgf/cm² , 435 psi}?	Yes	Go to Step 14.
10		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 .) Fuel pressure sensor (See FUEL PRESSURE SENSOR INSPECTION .) High pressure fuel pump (See HIGH PRESSURE FUEL PUMP INSPECTION .) If there is any malfunction: Repair or replace the malfunctioning part according to the inspection results. If there is no malfunction: Go to Step 13. Higher than 3 MPa {31 kgf/cm² , 435 psi}: Go to the next step.
11	DETERMINE IF MALFUNCTION CAUSE IS FUEL PRESSURE SENSOR OR HIGH PRESSURE FUEL PUMP Is the vehicle acceleration performance normal?	Yes	Go to the next step.
11		No	Go to Step 13.
12	INSPECT FUEL PRESSURE SENSOR Inspect the fuel pressure sensor. (See FUEL PRESSURE SENSOR INSPECTION .) Is there any malfunction?	Yes	Replace the fuel distributor. (See FUEL INJECTOR REMOVAL/INSTALLATION .)
12		No	Go to Step 14.
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 .)
13		No	Replace the high pressure fuel pump. (See HIGH PRESSURE FUEL PUMP REMOVAL/INSTALLATION .)
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 .) 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 .)
15	INSPECT ENGINE COMPRESSION Measure the compression pressure for each cylinder. (See COMPRESSION INSPECTION .) Are compression pressures within specification? Specification: Compression [SKYACTIV-G 2.0] Standard: 885 kPa {9.02 kgf/cm² , 128 psi} (300 RPM) Minimum: 708 kPa {7.22 kgf/cm² , 103 psi} (300 RPM) Maximum difference between cylinders: 148 kPa {1.51 kgf/cm² , 21.5 psi} (250 RPM) Compression [SKYACTIV-G 2.5] 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: 160 kPa {1.63 kgf/cm² , 23.2 psi} (250 RPM) NOTE: Because the SKYACTIV-G 2.0 and SKYACTIV-G 2.5 retards the intake valve closing timing, compression pressure is low.	Yes	Go to Step 21.
15		No	Go to the next step.
16	INSPECT ELECTRIC VARIABLE VALVE TIMING DRIVER Inspect the electric variable valve timing driver. (See ELECTRIC VARIABLE VALVE TIMING MOTOR/DRIVER INSPECTION .) Is there any malfunction?	Yes	Replace the electric variable valve timing motor/driver. (See ELECTRIC VARIABLE VALVE TIMING MOTOR/DRIVER REMOVAL/INSTALLATION .)
16		No	Go to the next step.
17	INSPECT ELECTRIC VARIABLE VALVE TIMING MOTOR Inspect the electric variable valve timing motor. (See ELECTRIC VARIABLE VALVE TIMING MOTOR/DRIVER INSPECTION .) Is there any malfunction?	Yes	Replace the electric variable valve timing motor/driver. (See ELECTRIC VARIABLE VALVE TIMING MOTOR/DRIVER REMOVAL/INSTALLATION .)
17		No	Go to the next step.
18	INSPECT ELECTRIC VARIABLE VALVE TIMING ACTUATOR Inspect the electric variable valve timing actuator. (See ELECTRIC VARIABLE VALVE TIMING ACTUATOR INSPECTION .) Is there any malfunction?	Yes	Replace the electric variable valve timing actuator. (See ELECTRIC VARIABLE VALVE TIMING ACTUATOR, HYDRAULIC VARIABLE VALVE TIMING ACTUATOR REMOVAL/INSTALLATION .)
18		No	Go to the next step.
19	INSPECT HYDRAULIC VARIABLE VALVE TIMING CONTROL SYSTEM OPERATION Perform the Hydraulic Variable Valve Timing Control System Operation Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION .) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
19		No	Go to the next step.
20	INSPECT FOR MALFUNCTION DUE TO DEVIATED VALVE TIMING Inspect the valve timing (timing chain installation condition). (See TIMING CHAIN REMOVAL/INSTALLATION .) Is the valve timing normal?	Yes	Inspect for the following engine internal parts: Cylinder Piston ring Intake valve Exhaust valve Such as cylinder head gasket If there is any malfunction: Repair or replace the malfunctioning part according to the inspection results.
20		No	Adjust the valve timing to the correct timing.
21	INSPECT IGNITION SYSTEM OPERATION Perform the Spark Test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION .) Is the strong blue spark visible at each cylinder?	Yes	Go to the next step.
21		No	Repair or replace the malfunctioning part according to the inspection results.
22	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.
22		No	Go to the next step.
23	INSPECT IF MALFUNCTION CAUSE IS PCV VALVE OR INJECTOR DRIVER (PCM INTEGRATED) Inspect the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION .) Is there any malfunction?	Yes	Replace the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION .)
23		No	Injector driver malfunction. Replace the PCM. (See PCM REMOVAL/INSTALLATION .) If the problem remains, overhaul the engine.
24	Verify the test results. If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX .) 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.