NO.11 ENGINE STALLS/QUITS, ENGINE RUNS ROUGH, MISSES, BUCK/JERK, HESITATION/STUMBLE, SURGES [MZR 2.0 DISI]

11	ENGINE STALLS/QUITS—ACCELERATION/CRUISE ENGINE RUNS ROUGH—ACCELERATION/CRUISE MISSES—ACCELERATION/CRUISE BUCK/JERK—ACCELERATION/CRUISE/DECELERATION HESITATION/STUMBLE—ACCELERATION SURGES—ACCELERATION/CRUISE
DESCRIPTION	• Engine stops unexpectedly at beginning of acceleration or during acceleration. • Engine stops unexpectedly while cruising. • Engine speed fluctuates during acceleration or cruising. • Engine misses during acceleration or cruising. • Vehicle bucks/jerks during acceleration, cruising, or deceleration. • Momentary pause at beginning of acceleration or during acceleration. • Momentary minor irregularity in engine output.
POSSIBLE CAUSE	• Drive-by-wire control system operates with brake override system (GH1***-442043) • Poor fuel quality • Air leakage from intake-air system • Intake-air system restriction • Air cleaner restriction • Clutch slippage (MTX) • Fuel leakage • Vacuum leakage • Engine mount installation looseness • PCM DTC is stored • Engine overheating • Main relay intermittent malfunction • Erratic or no signal from CMP sensor • Erratic signal from CKP sensor • Erratic signal to PCM ― APP sensor or related circuit malfunction ― ECT sensor or related circuit malfunction ― Fuel pressure sensor or related circuit malfunction ― IAT sensor 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 and VSS • EGR system malfunction • Improper operation of A/C system • Improper operation of electronic throttle control system • Throttle body malfunction • Variable swirl system malfunction • Purge solenoid valve malfunction • Exhaust system and/or TWC restriction • Spark plug malfunction • 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-in high pressure fuel pump) malfunction ― Relief valve (built-in fuel delivery pipe) malfunction ― Fuel line restriction or clogging ― Fuel pump mechanical malfunction • Incorrect fuel injection timing • Fuel injector malfunction • Improper valve timing due to jumping out timing chain • Low engine compression • PCV valve malfunction • Injector driver (built-in PCM) malfunction • Check valve (two-way) malfunction • ATX 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 [MZR 2.0 DISI].) (See AFTER SERVICE PRECAUTION [MZR 2.0 DISI].) 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 STALLS/QUITS—ACCELERATION/CRUISE

ENGINE RUNS ROUGH—ACCELERATION/CRUISE

MISSES—ACCELERATION/CRUISE

BUCK/JERK—ACCELERATION/CRUISE/DECELERATION

HESITATION/STUMBLE—ACCELERATION

SURGES—ACCELERATION/CRUISE

DESCRIPTION

• Engine stops unexpectedly at beginning of acceleration or during acceleration.

• Engine stops unexpectedly while cruising.

• Engine speed fluctuates during acceleration or cruising.

• Engine misses during acceleration or cruising.

• Vehicle bucks/jerks during acceleration, cruising, or deceleration.

• Momentary pause at beginning of acceleration or during acceleration.

• Momentary minor irregularity in engine output.

POSSIBLE CAUSE

• Drive-by-wire control system operates with brake override system (GH1***-442043)

• Poor fuel quality

• Air leakage from intake-air system

• Intake-air system restriction

• Air cleaner restriction

• Clutch slippage (MTX)

• Fuel leakage

• Vacuum leakage

• Engine mount installation looseness

• PCM DTC is stored

• Engine overheating

• Main relay intermittent malfunction

• Erratic or no signal from CMP sensor

• Erratic signal from CKP sensor

• Erratic signal to PCM

― APP sensor or related circuit malfunction

― ECT sensor or related circuit malfunction

― Fuel pressure sensor or related circuit malfunction

― IAT sensor 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 and VSS

• EGR system malfunction

• Improper operation of A/C system

• Improper operation of electronic throttle control system

• Throttle body malfunction

• Variable swirl system malfunction

• Purge solenoid valve malfunction

• Exhaust system and/or TWC restriction

• Spark plug malfunction

• 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-in high pressure fuel pump) malfunction

― Relief valve (built-in fuel delivery pipe) malfunction

― Fuel line restriction or clogging

― Fuel pump mechanical malfunction

• Incorrect fuel injection timing

• Fuel injector malfunction

• Improper valve timing due to jumping out timing chain

• Low engine compression

• PCV valve malfunction

• Injector driver (built-in PCM) malfunction

• Check valve (two-way) malfunction

• ATX 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 [MZR 2.0 DISI].) (See AFTER SERVICE PRECAUTION [MZR 2.0 DISI].)

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^*1	CONFIRM DRIVE-BY-WIRE CONTROL SYSTEM OPERATES WITH BRAKE OVERRIDE SYSTEM • Retrieve any PCM DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZR 2.0 DISI].) • Are any DTCs present?	Yes	Go to the applicable DTC inspection. (drive-by-wire control system operates with brake override system.) (See DTC P2299:00 [MZR 2.0 DISI].)
No	Go to the next step.
2	Inspect for following: • Fuel quality (proper octane, contamination, winter/summer blend) • Air leakage from intake-air system • Intake-air system restriction • Air cleaner element • Clutch slippage (MTX) • Fuel leakage from fuel line • Vacuum leakage • Engine mount looseness Is there any malfunction?	Yes	Service if necessary. • Repeat this step.
No	Go to the next step.
3	Retrieve any PCM DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZR 2.0 DISI].) Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [MZR 2.0 DISI].)
No	Go to the next step.
4	Access the ECT PID using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZR 2.0 DISI].) Is the ECT PID value less than 116 °C {241 °F} during driving?	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 [MZR 2.0 DISI].)
5	Perform the Main Relay Operation Inspection with wiggle the related harness. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 2.0 DISI].) Does the main relay operate properly?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part according to the inspection results.
6	Inspect the CMP sensor and CKP sensor for the following: • Installation condition (See CAMSHAFT POSITION (CMP) SENSOR REMOVAL/INSTALLATION [MZR 2.0 DISI].) (See CRANKSHAFT POSITION (CKP) SENSOR REMOVAL/INSTALLATION [MZR 2.0 DISI].) • Damaged trigger wheel and camshaft • Open or short circuit in related circuit Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
No	Go to the next step.
7	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 [MZR 2.0 DISI].) • APP • ECT • FP • IAT • LONGFT1 • MAF • MAP • O2S11 • O2S12 • SHTFT1 • VSS Do the PIDs indicate the correct values under the trouble condition? (See PCM INSPECTION [MZR 2.0 DISI].)	Yes	Go to the next step.
No	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 [MZR 2.0 DISI].)
8	Perform the EGR Control System Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 2.0 DISI].) Does the EGR system operate properly?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part according to the inspection results.
9	Perform the A/C Cut-off Control System Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 2.0 DISI].) 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.
10	Perform the TP sweep inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 2.0 DISI].) Does the electronic throttle control system work properly?	Yes	Visually inspect the throttle body (damage/scratching). • 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.
No	Repair or replace the malfunctioning part according to the inspection results.
11	Perform the Variable Swirl System Operation Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 2.0 DISI].) Does the variable swirl system work properly?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part according to the inspection results.
12	Perform the Purge Control System Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 2.0 DISI].) 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.
13	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.
No	Go to the next step.
14	Perform the Spark Test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 2.0 DISI].) 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.
15	Access the FUEL_PRES PID using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZR 2.0 DISI].) Is the FUEL_PRES PID value within the specification? (See PCM INSPECTION [MZR 2.0 DISI].)	Yes	Go to Step 20.
No	Go to the next step.
16	Is the vehicle accelerate performance normally?	Yes	Go to the next step.
No	Go to Step 18.
17	Inspect the fuel pressure sensor. (See FUEL PRESSURE SENSOR INSPECTION [MZR 2.0 DISI].) Is there any malfunction?	Yes	Replace the fuel delivery pipe. (See FUEL INJECTOR REMOVAL/INSTALLATION [MZR 2.0 DISI].)
No	Go to Step 20.
18	Switch the ignition to 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	Repair or replace the wiring harness for a possible short to ground. • If the malfunction remains: ― Replace the PCM. (damage to driver in PCM) (See PCM REMOVAL/INSTALLATION [MZR 2.0 DISI].)
No	Go to the next step.
19	Replace the high pressure fuel pump. (See HIGH PRESSURE FUEL PUMP REMOVAL/INSTALLATION [MZR 2.0 DISI].) Access the FUEL_PRES PID using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZR 2.0 DISI].) Is the FUEL_PRES PID value within the specification? (See PCM INSPECTION [MZR 2.0 DISI].)	Yes	High pressure fuel pump or spill valve control solenoid valve (built-in high pressure fuel pump) malfunction. • Symptom troubleshooting is completed. • Go to Step 24.
No	Relief valve (built-in fuel delivery pipe) malfunction. • Replace the fuel delivery pipe. (See FUEL INJECTOR REMOVAL/INSTALLATION [MZR 2.0 DISI].)
20	Connect the fuel pressure gauge between fuel pump and high pressure fuel pump. Measure the low side fuel pressure. (See FUEL LINE PRESSURE INSPECTION [MZR 2.0 DISI].) Is the low side fuel pressure within the specification?	Yes	Go to the next step.
No	Inspect for following: • Fuel line restriction • Fuel filter clogging ― 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 [MZR 2.0 DISI].)
21	Perform the Fuel Injector Operation Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 2.0 DISI].) Do the fuel injectors operate properly?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part according to the inspection results.
22	Measure the compression pressure for each cylinder. (See COMPRESSION INSPECTION [MZR 2.0 DISI].) Are the compression pressures within the specification?	Yes	Go to the next step.
No	Inspect for following: • Damaged valve seat • Worn valve stem and valve guide • Worn or stuck piston ring • Worn piston, piston ring or cylinder • Improper valve timing Service if necessary.
23	Inspect the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [MZR 2.0 DISI].) Is there any malfunction?	Yes	Replace the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [MZR 2.0 DISI].)
No	Inspect the check valve (two-way). • If there is any malfunction: ― Repair or replace the malfunctioning part according to the inspection results. • If there is no malfunction: ― Injector driver is malfunction. • Replace the PCM. (See PCM REMOVAL/INSTALLATION [MZR 2.0 DISI].) If the malfunction remains: • Inspect the transaxle internal components (ATX). • Overhaul the engine.
24	Verify the test results. • If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZR 2.0 DISI].) • If a 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, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZR 2.0 DISI].)

STEP

INSPECTION

RESULTS

ACTION

1^*1

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

• Retrieve any PCM DTCs using the M-MDS.

(See ON-BOARD DIAGNOSTIC TEST [MZR 2.0 DISI].)

• Are any DTCs present?

Yes

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

(See DTC P2299:00 [MZR 2.0 DISI].)

Go to the next step.

Inspect for following:

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

• Air leakage from intake-air system

• Intake-air system restriction

• Air cleaner element

• Clutch slippage (MTX)

• Fuel leakage from fuel line

• Vacuum leakage

• Engine mount looseness

Is there any malfunction?

Yes

Service if necessary.

• Repeat this step.

Go to the next step.

Retrieve any PCM DTCs using the M-MDS.

(See ON-BOARD DIAGNOSTIC TEST [MZR 2.0 DISI].)

Are any DTCs present?

Yes

Go to the applicable DTC inspection.

(See DTC TABLE [MZR 2.0 DISI].)

Go to the next step.

Access the ECT PID using the M-MDS.

(See ON-BOARD DIAGNOSTIC TEST [MZR 2.0 DISI].)

Is the ECT PID value less than 116 °C {241 °F} during driving?

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 [MZR 2.0 DISI].)

Perform the Main Relay Operation Inspection with wiggle the related harness.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 2.0 DISI].)

Does the main relay operate properly?

Yes

Go to the next step.

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

Inspect the CMP sensor and CKP sensor for the following:

• Installation condition

(See CAMSHAFT POSITION (CMP) SENSOR REMOVAL/INSTALLATION [MZR 2.0 DISI].)

(See CRANKSHAFT POSITION (CKP) SENSOR REMOVAL/INSTALLATION [MZR 2.0 DISI].)

• Damaged trigger wheel and camshaft

• Open or short circuit in related circuit

Is there any malfunction?

Yes

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

Go to the next step.

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 [MZR 2.0 DISI].)

• APP

• ECT

• FP

• IAT

• LONGFT1

• MAF

• MAP

• O2S11

• O2S12

• SHTFT1

• VSS

Do the PIDs indicate the correct values under the trouble condition?

(See PCM INSPECTION [MZR 2.0 DISI].)

Yes

Go to the next step.

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 [MZR 2.0 DISI].)

Perform the EGR Control System Inspection.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 2.0 DISI].)

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 A/C Cut-off Control System Inspection.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 2.0 DISI].)

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 TP sweep inspection.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 2.0 DISI].)

Does the electronic throttle control system work properly?

Yes

Visually inspect the throttle body (damage/scratching).

• 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.

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

Perform the Variable Swirl System Operation Inspection.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 2.0 DISI].)

Does the variable swirl system work properly?

Yes

Go to the next step.

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

Perform the Purge Control System Inspection.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 2.0 DISI].)

Does the purge solenoid valve work properly?

Yes

Go to the next step.

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

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.

Go to the next step.

Perform the Spark Test.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 2.0 DISI].)

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 [MZR 2.0 DISI].)

Is the FUEL_PRES PID value within the specification?

(See PCM INSPECTION [MZR 2.0 DISI].)

Yes

Go to Step 20.

Go to the next step.

Is the vehicle accelerate performance normally?

Yes

Go to the next step.

Go to Step 18.

Inspect the fuel pressure sensor.

(See FUEL PRESSURE SENSOR INSPECTION [MZR 2.0 DISI].)

Is there any malfunction?

Yes

Replace the fuel delivery pipe.

(See FUEL INJECTOR REMOVAL/INSTALLATION [MZR 2.0 DISI].)

Go to Step 20.

Switch the ignition to 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

Repair or replace the wiring harness for a possible short to ground.

• If the malfunction remains:

― Replace the PCM. (damage to driver in PCM)

(See PCM REMOVAL/INSTALLATION [MZR 2.0 DISI].)

Go to the next step.

Replace the high pressure fuel pump.

(See HIGH PRESSURE FUEL PUMP REMOVAL/INSTALLATION [MZR 2.0 DISI].)

Access the FUEL_PRES PID using the M-MDS.

(See ON-BOARD DIAGNOSTIC TEST [MZR 2.0 DISI].)

Is the FUEL_PRES PID value within the specification?

(See PCM INSPECTION [MZR 2.0 DISI].)

Yes

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

• Symptom troubleshooting is completed.

• Go to Step 24.

Relief valve (built-in fuel delivery pipe) malfunction.

• Replace the fuel delivery pipe.

(See FUEL INJECTOR REMOVAL/INSTALLATION [MZR 2.0 DISI].)

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

Measure the low side fuel pressure.

(See FUEL LINE PRESSURE INSPECTION [MZR 2.0 DISI].)

Is the low side fuel pressure within the specification?

Yes

Go to the next step.

Inspect for following:

• Fuel line restriction

• Fuel filter clogging

― 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 [MZR 2.0 DISI].)

Perform the Fuel Injector Operation Inspection.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 2.0 DISI].)

Do the fuel injectors operate properly?

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 [MZR 2.0 DISI].)

Are the compression pressures within the specification?

Yes

Go to the next step.

Inspect for following:

• Damaged valve seat

• Worn valve stem and valve guide

• Worn or stuck piston ring

• Worn piston, piston ring or cylinder

• Improper valve timing

Service if necessary.

Inspect the PCV valve.

(See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [MZR 2.0 DISI].)

Is there any malfunction?

Yes

Replace the PCV valve.

(See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [MZR 2.0 DISI].)

Inspect the check valve (two-way).

• If there is any malfunction:

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

• If there is no malfunction:

― Injector driver is malfunction.

• Replace the PCM.

(See PCM REMOVAL/INSTALLATION [MZR 2.0 DISI].)

If the malfunction remains:

• Inspect the transaxle internal components (ATX).

• Overhaul the engine.

Verify the test results.

• If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZR 2.0 DISI].)

• If a 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, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZR 2.0 DISI].)