NO.7 SLOW RETURN TO IDLE [ZJ, ZY]
id0103b0801300
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7 |
SLOW RETURN TO IDLE |
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DESCRIPTION
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• The engine takes more time than normal to return to idle speed.
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POSSIBLE CAUSE
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• Continuous memory DTC is stored
• Thermostat malfunction (stuck open)
• ECT sensor malfunction
• Air leakage from intake-air system
• Throttle body contamination
• PCM malfunction
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Diagnostic procedure
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STEP |
INSPECTION |
ACTION |
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1
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Perform the KOER self test.
(See KOEO/KOER SELF TEST [ZJ, ZY].)
Are any continuous memory DTCs present?
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Yes
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Go to the appropriate DTC inspection.
(See DTC TABLE [ZJ, ZY].)
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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 is above 90 °C {194 °F}.
Does the ECT PID increase dull at thermostat initial opening temperature?
• Thermostat initial opening temperature:
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Yes
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Thermostat operation is normal.
• Go to Step 4.
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No
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Go to the next step.
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3
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Cool down the engine.
Remove the thermostat.
Inspect the thermostat.
Is there any malfunction?
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Yes
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Replace the thermostat.
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No
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Inspect the characteristic of the ECT sensor.
Replace the ECT sensor, if necessary.
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4
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Visually inspect the throttle body.
Is the throttle body free of contaminations?
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Yes
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Inspect for air leakage from 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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5
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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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