NO.8 ENGINE RUNS ROUGH/ROLLING IDLE [L3 Turbo]

8	ENGINE RUNS ROUGH/ROLLING IDLE
DESCRIPTION	• Engine speed fluctuates between the specified idle speed and lower speed, and engine shakes excessively. • Idle speed is too slow and the engine shakes excessively.
POSSIBLE CAUSE	• Air leakage from intake-air system • A/C system improper operation • Erratic signal to ignition coil • Spark plug malfunction • Purge solenoid valve malfunction • Improper operation of electronic throttle control system • EGR valve malfunction • Low engine compression or excessive unbalance for each cylinder • Improper valve timing • Improper variable valve timing control system • Poor fuel quality • PCV valve malfunction • Intake-air system restriction • Exhaust system or TWC restriction or clogging • Disconnected electrical connectors • Inadequate fuel pressure (high or low pressure side) • Fuel pressure sensor or related circuit malfunction • Spill valve control solenoid valve malfunction (built-in high pressure fuel pump) • Relief valve malfunction (built-in delivery pipe) • Fuel pump (low-side) body mechanical malfunction • Fuel filter restriction or clogging • Fuel leakage • Incorrect fuel injection timing • Unbalanced fuel injection amount for each cylinder • High pressure fuel pump malfunction • Fuel injector malfunction • Erratic signal from CKP sensor • Erratic or no signal from CMP sensor • ECT sensor or related circuit malfunction • MAP sensor or related circuit malfunction • APP sensor or related circuit malfunction • MAF sensor malfunction • Incorrect or no load signal input • Engine overheating • Vacuum leakage 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 [L3 Turbo].) (See AFTER SERVICE PRECAUTION [L3 Turbo].) 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 material.

ENGINE RUNS ROUGH/ROLLING IDLE

DESCRIPTION

• Engine speed fluctuates between the specified idle speed and lower speed, and engine shakes excessively.

• Idle speed is too slow and the engine shakes excessively.

POSSIBLE CAUSE

• Air leakage from intake-air system

• A/C system improper operation

• Erratic signal to ignition coil

• Spark plug malfunction

• Purge solenoid valve malfunction

• Improper operation of electronic throttle control system

• EGR valve malfunction

• Low engine compression or excessive unbalance for each cylinder

• Improper valve timing

• Improper variable valve timing control system

• Poor fuel quality

• PCV valve malfunction

• Intake-air system restriction

• Exhaust system or TWC restriction or clogging

• Disconnected electrical connectors

• Inadequate fuel pressure (high or low pressure side)

• Fuel pressure sensor or related circuit malfunction

• Spill valve control solenoid valve malfunction (built-in high pressure fuel pump)

• Relief valve malfunction (built-in delivery pipe)

• Fuel pump (low-side) body mechanical malfunction

• Fuel filter restriction or clogging

• Fuel leakage

• Incorrect fuel injection timing

• Unbalanced fuel injection amount for each cylinder

• High pressure fuel pump malfunction

• Fuel injector malfunction

• Erratic signal from CKP sensor

• Erratic or no signal from CMP sensor

• ECT sensor or related circuit malfunction

• MAP sensor or related circuit malfunction

• APP sensor or related circuit malfunction

• MAF sensor malfunction

• Incorrect or no load signal input

• Engine overheating

• Vacuum leakage

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 [L3 Turbo].) (See AFTER SERVICE PRECAUTION [L3 Turbo].)

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 material.

STEP	INSPECTION	RESULTS	ACTION
1	Inspect for the following: • Fuel quality (proper octane, contamination, winter/summer blend) • Intake-air system restriction or leakage • Electrical connectors connection • Fuel leakage in fuel system • Vacuum leakage Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results. Repeat this step.
No	Go to the next step.
2	Turn the ignition switch to the ON position. Retrieve any DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [L3 Turbo].) Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [L3 Turbo].)
No	Go to the next step.
3	Access the ECT PID using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [L3 Turbo].) Verify that the ECT PID value is less than 116 °C {241 °F} during driving. Is the ECT PID value less than specification? (See PCM INSPECTION [L3 Turbo].)	Yes	Go to the next step.
No	The cause of this concern could be from the cooling system overheating. Perform the symptom troubleshooting “NO.17 COOLING SYSTEM CONCERNS-OVERHEATING”. (See NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [L3 Turbo].)
4	Perform the A/C Cut-off Control System Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L3 Turbo].) Does the A/C cut-off operation work properly?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part according to the inspection results.
5	Perform the EGR Control System Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L3 Turbo].) Does the EGR system operate properly?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part according to the inspection results.
6	Perform the TP sweep inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L3 Turbo].) Does the electronic throttle control system work properly?	Yes	Visually inspect the throttle body (damage/scratching.) • If normal: ― Go to the next step. • If not: ― Repair or replace the malfunctioning part according to the inspection results.
No	Repair or replace the malfunctioning part according to the inspection results.
7	Perform the Purge Control System Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L3 Turbo].) Does the purge solenoid valve work properly?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part according to the inspection results.
8	Perform the Variable Valve Timing Control System Operation Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L3 Turbo].) Does the variable valve timing control system work properly?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part according to the inspection results.
9	Inspect the CMP and CKP sensor for the following: • Installation condition (See CAMSHAFT POSITION (CMP) SENSOR REMOVAL/INSTALLATION [L3 Turbo].) (See CRANKSHAFT POSITION (CKP) SENSOR REMOVAL/INSTALLATION [L3 Turbo].) • Damaged trigger wheel and camshaft • Open or short circuit in the wiring harnesses Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
No	Go to the next step.
10	Access the following PIDs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [L3 Turbo].) • AC_REQ • APP1 • APP2 • ECT • MAF • MAP • PSP (PCM terminal 1AD) Do the PIDs indicate the correct values under trouble condition? (See PCM INSPECTION [L3 Turbo].)	Yes	Go to the next step.
No	Inspect the suspected parts and related wiring harness. • If normal: ― Perform the “INTERMITTENT CONCERN TROUBLESHOOTING” procedure. (See INTERMITTENT CONCERN TROUBLESHOOTING [L3 Turbo].) • If not: ― Repair or replace the malfunctioning part according to the inspection results.
11	Inspect for restriction in the exhaust system and TWC. Is there any restriction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
No	Go to the next step.
12	Perform the Spark Test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L3 Turbo].) Is a strong blue spark visible at each cylinder?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part according to the inspection results.
13	Access the FUEL_PRES PID using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [L3 Turbo].) Is the FUEL_PRES PID value within the specification? (See PCM INSPECTION [L3 Turbo].)	Yes	Go to Step 17.
No	Go to the next step.
14	Is the vehicle accelerate performance normally?	Yes	Go to the next step.
No	Go to Step 16.
15	Inspect the fuel pressure sensor. (See FUEL PRESSURE SENSOR INSPECTION [L3 Turbo].) Is there any malfunction?	Yes	Replace the fuel delivery pipe. (See FUEL INJECTOR REMOVAL/INSTALLATION [L3 Turbo].)
No	Go to Step 17.
16	Replace the high pressure fuel pump. (See HIGH PRESSURE FUEL PUMP REMOVAL/INSTALLATION [L3 Turbo].) Access the FUEL_PRES PID using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [L3 Turbo].) Is the FUEL_PRES PID value within the specification? (See PCM INSPECTION [L3 Turbo].)	Yes	High pressure fuel pump or spill valve control solenoid valve (built-in high pressure fuel pump) malfunction. • Go to Step 21.
No	Relief valve malfunction. • Replace the fuel delivery pipe. (See FUEL INJECTOR REMOVAL/INSTALLATION [L3 Turbo].)
17	Connect the fuel pressure gauge between the fuel pump and the high pressure fuel pump. Measure the fuel pressure line of the low pressure side. (See FUEL LINE PRESSURE INSPECTION [L3 Turbo].) Is the fuel pressure within the specification?	Yes	Go to the next step.
No	Inspect for the following: • Fuel line restriction • Fuel filter clogging • If normal: ― Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [L3 Turbo].) • If not: ― Repair or replace the malfunctioning part according to the inspection results.
18	Perform the Fuel Injector Operation Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L3 Turbo].) Do the fuel injectors operate normally?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part according to the inspection results.
19	Measure the compression pressure for each cylinder. (See COMPRESSION INSPECTION [L3 Turbo].) Are the compression pressures within the specification?	Yes	Go to the next step.
No	Inspect for the following: • Damaged valve seat • Worn valve stem and valve guide • Worn or stuck piston ring • Worn piston, piston ring or cylinder • Improper valve timing Repair or replace the malfunctioning part according to the inspection results.
20	Inspect the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [L3 Turbo].) Is there any malfunction?	Yes	Replace the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [L3 Turbo].)
No	Replace the PCM (injector driver circuit malfunction). (See PCM REMOVAL/INSTALLATION [L3 Turbo].) • If the problem remains: ― Repair or replace the malfunctioning part according to the inspection results.
21	Verify test results. • If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [L3 Turbo].) • If the malfunction remains, inspect the related Service Information and perform the 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.

STEP

INSPECTION

RESULTS

ACTION

Inspect for the following:

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

• Intake-air system restriction or leakage

• Electrical connectors connection

• Fuel leakage in fuel system

• Vacuum leakage

Is there any malfunction?

Yes

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

Repeat this step.

Go to the next step.

Turn the ignition switch to the ON position.

Retrieve any DTCs using the M-MDS.

(See ON-BOARD DIAGNOSTIC TEST [L3 Turbo].)

Are any DTCs present?

Yes

Go to the applicable DTC inspection.

(See DTC TABLE [L3 Turbo].)

Go to the next step.

Access the ECT PID using the M-MDS.

(See ON-BOARD DIAGNOSTIC TEST [L3 Turbo].)

Verify that the ECT PID value is less than 116 °C {241 °F} during driving.

Is the ECT PID value less than specification?

(See PCM INSPECTION [L3 Turbo].)

Yes

Go to the next step.

The cause of this concern could be from the cooling system overheating.

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

(See NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [L3 Turbo].)

Perform the A/C Cut-off Control System Inspection.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L3 Turbo].)

Does the A/C cut-off operation work properly?

Yes

Go to the next step.

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

Perform the EGR Control System Inspection.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L3 Turbo].)

Does the EGR system operate properly?

Yes

Go to the next step.

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

Perform the TP sweep inspection.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L3 Turbo].)

Does the electronic throttle control system work properly?

Yes

Visually inspect the throttle body (damage/scratching.)

• If normal:

― Go to the next step.

• If not:

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

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

Perform the Purge Control System Inspection.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L3 Turbo].)

Does the purge solenoid valve work properly?

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 [L3 Turbo].)

Does the variable valve timing control system work properly?

Yes

Go to the next step.

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

Inspect the CMP and CKP sensor for the following:

• Installation condition (See CAMSHAFT POSITION (CMP) SENSOR REMOVAL/INSTALLATION [L3 Turbo].) (See CRANKSHAFT POSITION (CKP) SENSOR REMOVAL/INSTALLATION [L3 Turbo].)

• Damaged trigger wheel and camshaft

• Open or short circuit in the wiring harnesses

Is there any malfunction?

Yes

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

Go to the next step.

Access the following PIDs using the M-MDS.

(See ON-BOARD DIAGNOSTIC TEST [L3 Turbo].)

• AC_REQ

• APP1

• APP2

• ECT

• MAF

• MAP

• PSP (PCM terminal 1AD)

Do the PIDs indicate the correct values under trouble condition?

(See PCM INSPECTION [L3 Turbo].)

Yes

Go to the next step.

Inspect the suspected parts and related wiring harness.

• If normal:

― Perform the “INTERMITTENT CONCERN TROUBLESHOOTING” procedure. (See INTERMITTENT CONCERN TROUBLESHOOTING [L3 Turbo].)

• If not:

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

Inspect for restriction in the exhaust system and TWC.

Is there any restriction?

Yes

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

Go to the next step.

Perform the Spark Test.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L3 Turbo].)

Is a strong blue spark visible at each cylinder?

Yes

Go to the next step.

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

Access the FUEL_PRES PID using the M-MDS.

(See ON-BOARD DIAGNOSTIC TEST [L3 Turbo].)

Is the FUEL_PRES PID value within the specification?

(See PCM INSPECTION [L3 Turbo].)

Yes

Go to Step 17.

Go to the next step.

Is the vehicle accelerate performance normally?

Yes

Go to the next step.

Go to Step 16.

Inspect the fuel pressure sensor.

(See FUEL PRESSURE SENSOR INSPECTION [L3 Turbo].)

Is there any malfunction?

Yes

Replace the fuel delivery pipe.

(See FUEL INJECTOR REMOVAL/INSTALLATION [L3 Turbo].)

Go to Step 17.

Replace the high pressure fuel pump.

(See HIGH PRESSURE FUEL PUMP REMOVAL/INSTALLATION [L3 Turbo].)

Access the FUEL_PRES PID using the M-MDS.

(See ON-BOARD DIAGNOSTIC TEST [L3 Turbo].)

Is the FUEL_PRES PID value within the specification?

(See PCM INSPECTION [L3 Turbo].)

Yes

High pressure fuel pump or spill valve control solenoid valve (built-in high pressure fuel pump) malfunction.

• Go to Step 21.

Relief valve malfunction.

• Replace the fuel delivery pipe. (See FUEL INJECTOR REMOVAL/INSTALLATION [L3 Turbo].)

Connect the fuel pressure gauge between the fuel pump and the high pressure fuel pump.

Measure the fuel pressure line of the low pressure side.

(See FUEL LINE PRESSURE INSPECTION [L3 Turbo].)

Is the fuel pressure within the specification?

Yes

Go to the next step.

Inspect for the following:

• Fuel line restriction

• Fuel filter clogging

• If normal:

― Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [L3 Turbo].)

• If not:

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

Perform the Fuel Injector Operation Inspection.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L3 Turbo].)

Do the fuel injectors operate normally?

Yes

Go to the next step.

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

Measure the compression pressure for each cylinder.

(See COMPRESSION INSPECTION [L3 Turbo].)

Are the compression pressures within the specification?

Yes

Go to the next step.

Inspect for the following:

• Damaged valve seat

• Worn valve stem and valve guide

• Worn or stuck piston ring

• Worn piston, piston ring or cylinder

• Improper valve timing

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

Inspect the PCV valve.

(See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [L3 Turbo].)

Is there any malfunction?

Yes

Replace the PCV valve.

(See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [L3 Turbo].)

Replace the PCM (injector driver circuit malfunction).

(See PCM REMOVAL/INSTALLATION [L3 Turbo].)

• If the problem remains:

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

Verify test results.

• If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [L3 Turbo].)

• If the malfunction remains, inspect the related Service Information and perform the 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.