NO.12 LACK/LOSS OF POWER-ACCELERATION/CRUISE [MZR 1.8, MZR 2.0, MZR 2.5]
id0103d4804800
12 |
LACK/LOSS OF POWER—ACCELERATION/CRUISE |
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DESCRIPTION
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• Performance is poor under load (such as power down when climbing hills).
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POSSIBLE CAUSE
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• Drive-by-wire control system operates with brake override system (from GH1***-429761,GH1***-442043,GH10**-206766,GH10**-210449,GH****-210421)
• Poor fuel quality
• Air leakage from intake air system
• Intake air system restriction
• Improper installation of EGR valve
• Vacuum leakage
• Clutch slippage (MTX)
• PCM DTC is stored
• Engine overheating
• Intake air temperature is too hot
• Erratic signal to PCM
• CKP sensor and teeth of crankshaft pulley malfunction
• Spark plug malfunction
• Fuel injector malfunction
• Improper operation of electronic throttle control system
• Exhaust system part malfunction
• Excessive or insufficient fuel pressure
• Improper operation of variable tumble control
• Improper operation of variable intake air control (MZR 2.0, MZR 2.5)
• Improper operation of A/C system
• Purge solenoid valve malfunction
• Evaporative emission control system malfunction
• CMP sensor and teeth of camshaft malfunction
• EGR valve malfunction
• Improper operation of EGR system
• Improper operation of variable valve timing control system (MZR 2.0, MZR 2.5)
• Low engine compression
• Improper valve timing
• PCV valve malfunction
• ATX internal malfunction (ATX)
• Brake dragging
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Diagnostic procedure
STEP |
INSPECTION |
RESULTS |
ACTION |
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1*1
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CONFIRM DRIVE-BY-WIRE CONTROL SYSTEM OPERATES WITH BRAKE OVERRIDE SYSTEM
• Perform the PCM DTC inspection using the M-MDS.
• Are any DTCs present?
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Yes
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Go to the applicable DTC inspection. (drive-by-wire control system operates with brake override system.)
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No
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Go to the next step.
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2
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Inspect the following:
• Fuel quality (such as proper octane, contamination, winter/summer blend)
• 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
• Restriction in the intake air system (such as the air cleaner element, fresh air duct)
• Vacuum connection
• Clutch slippage (MTX)
Is there any malfunction?
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Yes
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Repair or replace the malfunctioning part according to the inspection results.
Repeat Step 2.
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No
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Go to the next step.
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3
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Perform the PCM DTC inspection using the M-MDS.
Are any DTCs present?
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Yes
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Go to the applicable DTC inspection.
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No
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Go to the next step.
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4
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Is the engine overheating?
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Yes
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Go to the symptom troubleshooting “NO.17 COOLING SYSTEM CONCERNS-OVERHEATING”.
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No
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Go to the next step.
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5
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Access the following PIDs using the M-MDS:
• APP1
• APP2
• TP1
• TP2
• RPM
• MAF
• IAT
• VPWR
• VSS
Do the PIDs indicate the correct values under the trouble condition?
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Yes
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Go to the next step.
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No
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APP1, APP2 PIDs are not specified:
• Inspect if the output signal from the APP sensor changes smoothly.
TP1, TP2 PIDs are not specified:
• Inspect if the output signal from the TP sensor changes smoothly.
RPM PID is not specified:
• Inspect the CKP sensor and related wiring harness for vibration or an intermittent open/short circuit.
MAF PID is not specified:
• Inspect for an intermittent open circuit of the MAF sensor and the related wiring harness.
IAT PID is not specified:
• Inspect for an intermittent open circuit of the IAT sensor and the related wiring harness.
VPWR PID is not specified:
• Inspect for an intermittent open circuit.
VSS PID is not specified:
• Inspect for an intermittent open circuit in the VSS and related wiring harness.
Repair or replace the malfunctioning part according to the inspection results.
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6
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Visually inspect the CKP sensor and teeth of the crankshaft pulley.
Is there any malfunction?
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Yes
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Repair or replace the malfunctioning part according to the inspection results.
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No
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Go to the next step.
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7
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Inspect the spark plug condition.
Is the spark plug wet, covered with carbon or grayish white?
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Yes
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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.
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No
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Install the spark plugs on original cylinders, then go to the next step.
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8
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Perform the Electronic Throttle Control System Inspection.
Is there any malfunction?
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Yes
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Repair or replace the malfunctioning part according to the inspection results.
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No
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Go to the next step.
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9
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Visually inspect the exhaust system part.
Is there any malfunction?
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Yes
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Repair or replace the malfunctioning part according to the inspection results.
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No
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Go to the next step.
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10
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Inspect the fuel line pressure.
Is there any malfunction?
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Yes
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Zero or low:
• Inspect the fuel pump relay and the fuel pump circuit.
(See RELAY INSPECTION.)
• Inspect the fuel line for clogging.
High:
• Replace the fuel pump unit.
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No
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Go to the next step.
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11
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Perform the Variable Tumble Control Operation Inspection.
Is there any malfunction?
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Yes
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Repair or replace the malfunctioning part according to the inspection results.
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No
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MZR 1.8:
• Go to Step 13.
MZR 2.0, MZR 2.5:
• Go to the next step.
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12
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Perform the Variable Intake Air Control Operation Inspection.
Is there any malfunction?
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Yes
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Repair or replace the malfunctioning part according to the inspection results.
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No
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Go to the next step.
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13
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Connect the pressure gauges to the A/C low side and high side pressure lines.
Turn the A/C on and measure the low side and high side pressures.
Are the pressures within the specification?
(See REFRIGERANT PRESSURE CHECK.)
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Yes
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Go to the next step.
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No
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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:
• Repair or replace the malfunctioning part according to the inspection results.
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14
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Perform the A/C Cut-off Control System Inspection.
Is there any malfunction?
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Yes
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Inspect the A/C cut-off system components.
Repair or replace the malfunctioning part according to the inspection results.
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No
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Go to the next step.
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15
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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.
Switch the ignition to ON (engine off).
Is the engine stall now eliminated?
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Yes
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Inspect the following:
• Purge solenoid valve
• Evaporative emission control system
Repair or replace the malfunctioning part according to the inspection results.
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No
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Go to the next step.
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16
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Visually inspect the CMP sensor and teeth of the camshaft.
Is there any malfunction?
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Yes
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Repair or replace the malfunctioning part according to the inspection results.
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No
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Go to the next step.
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17
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Perform the EGR Control System Inspection.
Is there any malfunction?
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Yes
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Repair or replace the malfunctioning part according to the inspection results.
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No
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MZR 1.8:
• Go to Step 18.
MZR 2.0, MZR 2.5:
• Go to the next step.
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18
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Perform the Variable Valve Timing Control System Operation Inspection.
Is there any malfunction?
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Yes
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Repair or replace the malfunctioning part according to the inspection results.
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No
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Go to the next step.
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19
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Inspect the engine compression.
Is there any malfunction?
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Yes
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Repair or replace the malfunctioning part according to the inspection results.
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No
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Go to the next step.
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20
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Inspect the PCV valve.
Is there any malfunction?
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Yes
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Replace the PCV valve and the oil separator as a single unit, then go to the next step.
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No
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Inspect the following:
• Valve timing
• Internal transaxle part
• Brake system for dragging
Repair or replace the malfunctioning part according to the inspection results.
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21
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Verify test results.
• If normal, return to the diagnostic index to service any additional symptoms.
• If the malfunction remains, inspect the related Service Information and perform the repair or diagnosis.
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