NO.12 LACK/LOSS OF POWER-ACCELERATION/CRUISE [MZI-3.7]

id0103d2804800

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.
•  Vacuum leakage
•  Restriction in intake-air system
•  Air leakage from intake-air system parts
•  Poor fuel quality
•  PCM DTC is stored.
•  Engine overheating
•  Intake air temperature too hot
•  Erratic signal to PCM
―  APP sensor or related circuit malfunction
―  MAF sensor or related circuit malfunction
―  TP sensor or related circuit malfunction
―  IAT sensor or related circuit malfunction
―  CKP sensor or related circuit malfunction
―  VSS or related circuit malfunction
•  Erratic signal from CKP sensor
•  Fuel leakage from fuel injector
•  Fuel injector clogging
•  Throttle body restriction or clogged
•  Improper operation of drive-by-wire control system
•  Restriction in exhaust system
•  Inadequate fuel pressure
―  Open or short in fuel pump related circuit
―  Fuel pump mechanical malfunction
―  Fuel line restriction or clogging
―  Pressure regulator malfunction (built-in fuel pump unit)
•  Improper A/C system operation
•  Improper A/C cut-off operation
•  PCV valve malfunction
•  Purge control solenoid malfunction
•  Erratic signal or no signal from CMP sensor
•  Improper variable valve timing control operation
•  Low engine compression
•  Improper valve timing due to jumping out of timing chain
•  ATX malfunction
•  Brake dragging
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 [MZI-3.7].)(See AFTER SERVICE PRECAUTION [MZI-3.7].)
Caution
•  Disconnecting/connecting quick release connector without cleaning it may cause damage to fuel pipe and quick release connector. Always clean quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

Diagnostic procedure

STEP

INSPECTION

RESULTS

ACTION
1
Retrieve any PCM DTCs using the M-MDS.
(See ON-BOARD DIAGNOSTIC TEST [MZI-3.7 (PCM CONNECTOR (3 TYPES))].)
Is the DTC P2299:00 displayed?
Yes
Go to the appropriate DTC inspection. (Drive-by-wire control system operates with brake override system.)
(See DTC P2299:00 [MZI-3.7 (PCM CONNECTOR (3 TYPES))].)
No
Go to the next step.
2
Verify the following:
•  Vacuum connection
•  Restriction in intake-air system (such as air cleaner element, fresh air duct)
•  No air leakage from intake-air system
•  No restriction of intake-air system
•  Proper sealing of intake manifold and components attached to intake manifold
•  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
Turn the ignition switch to the ON position (Engine off).
Retrieve any PCM DTCs using the M-MDS.
(See ON-BOARD DIAGNOSTIC TEST [MZI-3.7 (PCM CONNECTOR (2 TYPES))].)
(See ON-BOARD DIAGNOSTIC TEST [MZI-3.7 (PCM CONNECTOR (3 TYPES))].)
Are there any DTCs displayed?
Yes
DTC is displayed:
•  Go to the appropriate DTC inspection.
No
No DTC is displayed:
•  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 [MZI-3.7].)
No
Go to the next step.
5
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 PCM PIDs and VSS using the M-MDS:
(See ON-BOARD DIAGNOSTIC TEST [MZI-3.7 (PCM CONNECTOR (2 TYPES))].)
(See ON-BOARD DIAGNOSTIC TEST [MZI-3.7 (PCM CONNECTOR (3 TYPES))].)
•  APP1
•  APP2
•  APP3 (PCM connector (2 types))
•  RPM
•  TP1
•  TP2
•  MAF
•  IAT
•  VSS
Monitor each PID while driving the vehicle.
Do the PIDs indicate the correct values under trouble condition?
(See PCM INSPECTION [MZI-3.7].)
Yes
Go to the next step.
No
APP1, APP2 or APP3 PID is not normal:
•  Inspect if output signal from APP sensor changes smoothly.
RPM PID is not normal:
•  Inspect the CKP sensor and related wiring harness for vibration or intermittent open/short circuit.
TP1 or TP2 PID is not normal:
•  Inspect if output signal from TP sensor changes smoothly.
MAF PID is not normal:
•  Inspect for open circuit of the MAF sensor and related wiring harness intermittently.
IAT PID is not normal:
•  Inspect for air suction in intake-air system.
―  If normal, inspect intermittent short circuit of IAT sensor and related wiring harnesses.
VSS PID is not normal:
•  Inspect for open circuit of VSS and related wiring harness intermittently.
Repair or replace the malfunctioning part according to the inspection results.
6
Inspect the CKP sensor.
(See CRANKSHAFT POSITION (CKP) SENSOR INSPECTION [MZI-3.7].)
Is the CKP sensor normal?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part according to the inspection results.
7
Verify the spark plug conditions.
Is the spark plug wet, covered with carbon or grayish white?
Yes
Spark plug is wet or covered with carbon:
•  Inspect for fuel leakage from fuel injector.
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.
Go to the next step.
8
Visually inspect the throttle valve.
Are any foreign materials adhere to around throttle valve?
Yes
Clean the throttle valve.
No
Go to the next step.
9
Perform the drive-by-wire control system operation inspection.
(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7].)
Does the drive-by-wire control system function properly?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part according to the inspection results.
10
Visually inspect the exhaust system part.
Is there any deformed exhaust system part?
Yes
Repair or replace the malfunctioning part according to the inspection results.
No
Go to the next step.
11
Inspect the fuel line pressure.
(See FUEL LINE PRESSURE INSPECTION [MZI-3.7].)
Is the fuel line pressure correct?
Yes
Go to the next step.
No
Zero or low:
•  Inspect the following:
―  Fuel pump relay
―  Fuel pump circuit
―  Fuel line for clogging
•  If there is no malfunction, replace the fuel pump unit. (Fuel pump or pressure regulator malfunction)
High:
•  Replace the fuel pump unit. (Pressure regulator malfunction)
12
Note
•  The following test is for stall concerns with the A/C on. If other symptoms exist, go to the next step.
Connect the pressure gauges to A/C low and high pressure side lines.
Turn the A/C on and measure low side and high side pressures.
(See REFRIGERANT PRESSURE CHECK.)
Are pressures within specifications?
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”.
For other symptoms:
•  Inspect the following:
―  Refrigerant charging amount
―  Condenser fan operation
•  Repair or replace the malfunctioning part according to the inspection results.
13
Inspect for A/C cut-off operation.
(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7].)
Does the A/C cut-off function properly?
Yes
Go to the next step.
No
Inspect the A/C cut-off system components.
Repair or replace the malfunctioning part according to the inspection results.
14
Note
•  The PCV valve cannot be reassembled once it is removed because the tabs will have bee n broken. Inspect the PCV valve without removing it from the vehicle.
Inspect the PCV valve with it installed.
(See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [MZI-3.7].)
Is the PCV valve normal?
Yes
Go to the next step.
No
Replace the PCV valve.
(See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [MZI-3.7].)
15
Disconnect the vacuum hose between purge solenoid valve and intake manifold from purge solenoid side.
Plug opening end of vacuum hose.
Drive the vehicle.
Does the engine condition improve?
Yes
Inspect the following:
•  If purge solenoid valve is stuck open.
•  EVAP control system
Repair or replace the malfunctioning part according to the inspection results.
No
Go to the next step.
16
Inspect the CMP sensor.
(See CAMSHAFT POSITION (CMP) SENSOR INSPECTION [MZI-3.7].)
Is the CMP sensor normal?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part according to the inspection results.
17
Inspect the variable valve timing control system operation.
(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7].)
Does the variable valve timing control function properly?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part according to the inspection results.
18
Is the engine compression correct?
Yes
Inspect the following:
•  Valve timing
•  Internal transaxle components
•  Brake system for dragging
Repair or replace the malfunctioning part according to the inspection results.
No
Inspect for cause.
Repair or replace the malfunctioning part according to the inspection results.
19
•  Verify test results.
―  If normal, return to diagnostic index to service any additional symptoms.
―  If malfunction remains, inspect related Service Information and perform repair or diagnosis.
•  If vehicle is repaired, troubleshooting completed.
•  If vehicle is not repaired or additional diagnostic information is not available, replace the PCM.