NO.12 LACK/LOSS OF POWER-ACCELERATION/CRUISE [LF, L5]

12	LACK/LOSS OF POWER—ACCELERATION/CRUISE
DESCRIPTION	• Performance is poor under load (such as power down when climbing hills).
POSSIBLE CAUSE	• Drive-by-wire control system operates with brake override system (From BL**-198281,BL1*-239890) • Improper operation of A/C system • Erratic signal or no signal from CMP sensor • Air leakage from intake air system parts • Restriction in intake air system • Intake air temperature too hot • Improper operation of variable intake air control • Improper operation of variable tumble control • Improper operation of electronic throttle control system • Purge solenoid valve malfunction • Improper operation of EGR valve • Brake dragging • Erratic signal from CKP sensor • Low engine compression • Vacuum leakage • Poor fuel quality • Erratic signal to ignition coil • Engine overheating • Throttle body malfunction • Spark plug malfunction • Improper valve timing due to jumping out of timing chain • Improper operation of variable valve timing control • Restriction in exhaust system • Intermittent open or short in fuel pump related circuit • Inadequate fuel pressure • Fuel pump mechanical malfunction • Fuel line restriction or clogging • Fuel leakage from fuel injector • Fuel injector clogging • Erratic signal from APP sensor • Erratic signal from TP sensor • Intermittent open or short circuit in MAF sensor, APP sensor, TP sensor, IAT sensor and VSS • ATX malfunction (ATX) • Clutch slippage (MTX) • PCV valve malfunction • PCM malfunction Warning The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before servicing the fuel system: • 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 injuries 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 [LF, L5].) (See AFTER SERVICE PRECAUTION [LF, L5].) Caution • Disconnecting/connecting the quick release connector without cleaning it may cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

LACK/LOSS OF POWER—ACCELERATION/CRUISE

DESCRIPTION

• Performance is poor under load (such as power down when climbing hills).

POSSIBLE CAUSE

• Drive-by-wire control system operates with brake override system (From BL****-198281,BL1***-239890)

• Improper operation of A/C system

• Erratic signal or no signal from CMP sensor

• Air leakage from intake air system parts

• Restriction in intake air system

• Intake air temperature too hot

• Improper operation of variable intake air control

• Improper operation of variable tumble control

• Improper operation of electronic throttle control system

• Purge solenoid valve malfunction

• Improper operation of EGR valve

• Brake dragging

• Erratic signal from CKP sensor

• Low engine compression

• Vacuum leakage

• Poor fuel quality

• Erratic signal to ignition coil

• Engine overheating

• Throttle body malfunction

• Spark plug malfunction

• Improper valve timing due to jumping out of timing chain

• Improper operation of variable valve timing control

• Restriction in exhaust system

• Intermittent open or short in fuel pump related circuit

• Inadequate fuel pressure

• Fuel pump mechanical malfunction

• Fuel line restriction or clogging

• Fuel leakage from fuel injector

• Fuel injector clogging

• Erratic signal from APP sensor

• Erratic signal from TP sensor

• Intermittent open or short circuit in MAF sensor, APP sensor, TP sensor, IAT sensor and VSS

• ATX malfunction (ATX)

• Clutch slippage (MTX)

• PCV valve malfunction

• PCM malfunction

Warning

The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before servicing the fuel system:

• 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 injuries 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 [LF, L5].) (See AFTER SERVICE PRECAUTION [LF, L5].)

Caution

• Disconnecting/connecting the quick release connector without cleaning it may cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

STEP	INSPECTION	RESULTS	ACTION
1^*1	CONFIRM DRIVE-BY-WIRE CONTROL SYSTEM OPERATES WITH BRAKE OVERRIDE SYSTEM • Retrieve the PCM DTC using the M-MDS. (See DTC P2299:00 [LF, L5]) • Is the DTC P2299 present?	Yes	Go to the applicable DTC inspection. (drive-by-wire control system operates with brake override system.) (See DTC P2299:00 [LF, L5])
No	Go to the next step.
2	Inspect the following: • Vacuum connection • Restriction in the intake air system (such as the air cleaner element, fresh air duct) • No air leakage from the intake air system • No restriction of the intake air system • Proper sealing of the intake manifold and components attached to the intake manifold; such as the EGR valve • Fuel quality (such as proper octane, contamination, winter/summer blend) Are all items normal?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part according to the inspection results. Repeat Step 2.
3	Connect the M-MDS to the DLC-2. Switch the ignition to ON (engine off). Retrieve any DTCs. (See ON-BOARD DIAGNOSTIC TEST [LF, L5].) Are any DTCs present?	Yes	Go to the appropriate DTC inspection. (See DTC TABLE [LF, L5].)
No	Go to the next step.
4	Is the engine overheating?	Yes	Go to the symptom troubleshooting “NO.17 COOLING SYSTEM CONCERNS-OVERHEATING”. (See NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [LF, L5].)
No	Go to the next step.
5	Connect the M-MDS to the DLC-2. Access the APP1, APP2, RPM, MAF, TP REL, IAT and VSS PIDs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [LF, L5].) Drive the vehicle while monitoring PIDs. Are the PIDs within specifications? (See PCM INSPECTION [LF, L5].)	Yes	Go to the next step.
No	APP1, APP2 PIDs: • Inspect if the output signal APP sensor changes smoothly. RPM PID: • Inspect the CKP sensor and the related wiring harness for vibration or intermittent open/short circuit or both. MAF PID: • Inspect for an intermittent open circuit of MAF sensor and the related wiring harness. TP REL PID: • Inspect if the output signal TP sensor changes smoothly. IAT PID: • Inspect for air suction in the intake air system. • If normal: ― Inspect for an intermittent short circuit in the IAT sensor and related wiring harnesses. VSS PID: • Inspect for an intermittent open circuit in the VSS and related wiring harness. Repair or replace the malfunctioning part according to the inspection results.
6	Visually inspect the CKP sensor and teeth of the crankshaft pulley. Are the CKP sensor and the teeth of the crankshaft pulley normal?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part according to the inspection results.
7	Inspect the spark plug condition. (See SPARK PLUG INSPECTION [LF, L5].) Are the spark plugs wet, covered with carbon or grayish white?	Yes	Spark plug is wet or covered with carbon: • Inspect the fuel injector for fuel leakage. • Inspect spark plug and high-tension lead. Spark plug is grayish white: • Inspect the fuel injector for clogging. Repair or replace the malfunctioning part according to the inspection results.
No	Install the spark plugs on original cylinders, then go to the next step.
8	Perform the Electronic Throttle Control System Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [LF, L5].) Does the electronic throttle control system function properly?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part according to the inspection results.
9	Visually inspect for deformed exhaust system parts. Are there any deformed exhaust system parts?	Yes	Repair or replace the malfunctioning part according to the inspection results.
No	Go to the next step.
10	Inspect the fuel line pressure. (See FUEL LINE PRESSURE INSPECTION [LF, L5].) Is the fuel line pressure correct?	Yes	Go to the next step.
No	Low: • Inspect the following: ― Fuel pump relay and fuel pump circuit ― Fuel line for clogging • If there is no malfunction: ― Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF, L5].) High: • Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF, L5].)
11	Perform the Variable Tumble Control Operation Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [LF, L5].) Does the variable tumble control function properly?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part according to the inspection results.
12	Perform the Variable Intake air Control Operation Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [LF, L5].) Does the variable intake air control function properly?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part according to the inspection results.
13	Note • The following test is for an engine stalling with the A/C on concern. If other symptoms exist, go to the next step. Connect the pressure gauge to the A/C low and high side pressure lines. Turn the A/C on and measure the low side and high side pressures. Are the pressures within specifications? (See REFRIGERANT PRESSURE CHECK.)	Yes	Go to the next step.
No	If the A/C is always on: • Go to 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 [LF, L5].) For other symptoms: • Inspect the following: ― Refrigerant charging amount ― Condenser fan operation • Repair or replace the malfunctioning part according to the inspection results.
14	Inspect the A/C cut-off operation. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [LF, L5].) Does the A/C cut-off function properly?	Yes	Go to the next step.
No	Inspect the A/C cut-off system components.
15	Disconnect the vacuum hose between the purge solenoid valve and the intake manifold from the purge solenoid valve side. Plug the open end of the vacuum hose. Drive the vehicle. Does the engine condition improve?	Yes	Inspect the following: • Purge solenoid valve is stuck open mechanically • EVAP control system Repair or replace the malfunctioning part according to the inspection results.
No	Go to the next step.
16	Visually inspect the CMP sensor and teeth of the camshaft. Are the CMP sensor and teeth of the camshaft normal?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part according to the inspection results.
17	Inspect the EGR system. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [LF, L5].) Is the EGR system normal?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part according to the inspection results.
18	Perform the Variable Valve Timing Control System Operation Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [LF, L5].) Does the variable valve timing control system function properly?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part according to the inspection results.
19	Is the engine compression correct? (See COMPRESSION INSPECTION [LF, L5].)	Yes	Go to the next step.
No	Inspect for cause. Repair or replace the malfunctioning part according to the inspection results.
20	Inspect the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [LF, L5].) Is there any malfunction?	Yes	Replace the PCV valve and oil separator as a single unit. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [LF, L5].)
No	Inspect the following: • Valve timing • Internal transaxle components (ATX) • Clutch (MTX) • Brake system for dragging Repair or replace the malfunctioning part according to the inspection results.
21	• Verify the test results. ― If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [LF, L5].) ― If the malfunction remains, inspect the related Service 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, replace the PCM. (See PCM REMOVAL/INSTALLATION [LF, L5].)

STEP

INSPECTION

RESULTS

ACTION

1^*1

CONFIRM DRIVE-BY-WIRE CONTROL SYSTEM OPERATES WITH BRAKE OVERRIDE SYSTEM

• Retrieve the PCM DTC using the M-MDS.

(See DTC P2299:00 [LF, L5])

• Is the DTC P2299 present?

Yes

Go to the applicable DTC inspection. (drive-by-wire control system operates with brake override system.)

(See DTC P2299:00 [LF, L5])

Go to the next step.

Inspect the following:

• Vacuum connection

• Restriction in the intake air system (such as the air cleaner element, fresh air duct)

• No air leakage from the intake air system

• No restriction of the intake air system

• Proper sealing of the intake manifold and components attached to the intake manifold; such as the EGR valve

• Fuel quality (such as proper octane, contamination, winter/summer blend)

Are all items normal?

Yes

Go to the next step.

Repair or replace the malfunctioning part according to the inspection results.

Repeat Step 2.

Connect the M-MDS to the DLC-2.

Switch the ignition to ON (engine off).

Retrieve any DTCs.

(See ON-BOARD DIAGNOSTIC TEST [LF, L5].)

Are any DTCs present?

Yes

Go to the appropriate DTC inspection.

(See DTC TABLE [LF, L5].)

Go to the next step.

Is the engine overheating?

Yes

Go to the symptom troubleshooting “NO.17 COOLING SYSTEM CONCERNS-OVERHEATING”.

(See NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [LF, L5].)

Go to the next step.

Connect the M-MDS to the DLC-2.

Access the APP1, APP2, RPM, MAF, TP REL, IAT and VSS PIDs using the M-MDS.

(See ON-BOARD DIAGNOSTIC TEST [LF, L5].)

Drive the vehicle while monitoring PIDs.

Are the PIDs within specifications?

(See PCM INSPECTION [LF, L5].)

Yes

Go to the next step.

APP1, APP2 PIDs:

• Inspect if the output signal APP sensor changes smoothly.

RPM PID:

• Inspect the CKP sensor and the related wiring harness for vibration or intermittent open/short circuit or both.

MAF PID:

• Inspect for an intermittent open circuit of MAF sensor and the related wiring harness.

TP REL PID:

• Inspect if the output signal TP sensor changes smoothly.

IAT PID:

• Inspect for air suction in the intake air system.

• If normal:

― Inspect for an intermittent short circuit in the IAT sensor and related wiring harnesses.

VSS PID:

• Inspect for an intermittent open circuit in the VSS and related wiring harness.

Repair or replace the malfunctioning part according to the inspection results.

Visually inspect the CKP sensor and teeth of the crankshaft pulley.

Are the CKP sensor and the teeth of the crankshaft pulley normal?

Yes

Go to the next step.

Repair or replace the malfunctioning part according to the inspection results.

Inspect the spark plug condition.

(See SPARK PLUG INSPECTION [LF, L5].)

Are the spark plugs wet, covered with carbon or grayish white?

Yes

Spark plug is wet or covered with carbon:

• Inspect the fuel injector for fuel leakage.

• Inspect spark plug and high-tension lead.

Spark plug is grayish white:

• Inspect the fuel injector for clogging.

Repair or replace the malfunctioning part according to the inspection results.

Install the spark plugs on original cylinders, then go to the next step.

Perform the Electronic Throttle Control System Inspection.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [LF, L5].)

Does the electronic throttle control system function properly?

Yes

Go to the next step.

Repair or replace the malfunctioning part according to the inspection results.

Visually inspect for deformed exhaust system parts.

Are there any deformed exhaust system parts?

Yes

Repair or replace the malfunctioning part according to the inspection results.

Go to the next step.

Inspect the fuel line pressure.

(See FUEL LINE PRESSURE INSPECTION [LF, L5].)

Is the fuel line pressure correct?

Yes

Go to the next step.

Low:

• Inspect the following:

― Fuel pump relay and fuel pump circuit

― Fuel line for clogging

• If there is no malfunction:

― Replace the fuel pump unit.

(See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF, L5].)

High:

• Replace the fuel pump unit.

(See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF, L5].)

Perform the Variable Tumble Control Operation Inspection.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [LF, L5].)

Does the variable tumble control function properly?

Yes

Go to the next step.

Repair or replace the malfunctioning part according to the inspection results.

Perform the Variable Intake air Control Operation Inspection.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [LF, L5].)

Does the variable intake air control function properly?

Yes

Go to the next step.

Repair or replace the malfunctioning part according to the inspection results.

Note

• The following test is for an engine stalling with the A/C on concern. If other symptoms exist, go to the next step.

Connect the pressure gauge to the A/C low and high side pressure lines.

Turn the A/C on and measure the low side and high side pressures.

Are the pressures within specifications?

(See REFRIGERANT PRESSURE CHECK.)

Yes

Go to the next step.

If the A/C is always on:

• Go to 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 [LF, L5].)

For other symptoms:

• Inspect the following:

― Refrigerant charging amount

― Condenser fan operation

• Repair or replace the malfunctioning part according to the inspection results.

Inspect the A/C cut-off operation.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [LF, L5].)

Does the A/C cut-off function properly?

Yes

Go to the next step.

Inspect the A/C cut-off system components.

Disconnect the vacuum hose between the purge solenoid valve and the intake manifold from the purge solenoid valve side.

Plug the open end of the vacuum hose.

Drive the vehicle.

Does the engine condition improve?

Yes

Inspect the following:

• Purge solenoid valve is stuck open mechanically

• EVAP control system

Repair or replace the malfunctioning part according to the inspection results.

Go to the next step.

Visually inspect the CMP sensor and teeth of the camshaft.

Are the CMP sensor and teeth of the camshaft normal?

Yes

Go to the next step.

Repair or replace the malfunctioning part according to the inspection results.

Inspect the EGR system.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [LF, L5].)

Is the EGR system normal?

Yes

Go to the next step.

Repair or replace the malfunctioning part according to the inspection results.

Perform the Variable Valve Timing Control System Operation Inspection.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [LF, L5].)

Does the variable valve timing control system function properly?

Yes

Go to the next step.

Repair or replace the malfunctioning part according to the inspection results.

Is the engine compression correct?

(See COMPRESSION INSPECTION [LF, L5].)

Yes

Go to the next step.

Inspect for cause.

Repair or replace the malfunctioning part according to the inspection results.

Inspect the PCV valve.

(See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [LF, L5].)

Is there any malfunction?

Yes

Replace the PCV valve and oil separator as a single unit.

(See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [LF, L5].)

Inspect the following:

• Valve timing

• Internal transaxle components (ATX)

• Clutch (MTX)

• Brake system for dragging

Repair or replace the malfunctioning part according to the inspection results.

• Verify the test results.

― If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [LF, L5].)

― If the malfunction remains, inspect the related Service 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, replace the PCM. (See PCM REMOVAL/INSTALLATION [LF, L5].)