NO.7 SLOW RETURN TO IDLE [MZR 1.8, MZR 2.0, MZR 2.5]
id0103d4801300
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7 |
SLOW RETURN TO IDLE |
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DESCRIPTION
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• Engine takes more time than normal to return to idle speed.
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POSSIBLE CAUSE
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• PCM DTC is stored
• ECT sensor malfunction
• Thermostat is stuck open
• Throttle body malfunction
• Air leakage from intake air system
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Diagnostic procedure
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STEP |
INSPECTION |
RESULTS |
ACTION |
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1
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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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2
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Access the ECT PID using the M-MDS.
Start the engine and warm it up to ECT PID value is above 90 °C {194 °F}.
Does the ECT PID increasing dull at thermostat initial opening temperature?
• Thermostat initial opening temperature: 80—84 °C {176—183 °F}
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Yes
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Inspect characteristic of the ECT sensor.
Repair or replace the malfunctioning part according to the inspection results.
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No
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Thermostat operation is normal:
• Go to the next step.
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3
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Is the throttle body free of contamination?
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Yes
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Inspect for air leakage from the intake air system components while racing the engine to higher speed.
Repair or replace the malfunctioning part according to the inspection results.
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No
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Clean or replace the throttle body.
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4
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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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