NO.7 SLOW RETURN TO IDLE [L8, LF]
id0103a0801300
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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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• ECT sensor malfunction
• Thermostat is stuck open
• PSP switch and related wiring harness malfunction
• Throttle body malfunction
• Air leakage from intake-air system
• PCM malfunction
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Diagnostic procedure
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STEP |
INSPECTION |
RESULTS |
ACTION |
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1
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Connect the M-MDS to the DLC-2.
Perform the KOEO/KOER self test and DTC Reading Procedure.
(See KOEO/KOER SELF TEST [L8, LF].)
Are any DTCs present?
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Yes
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Go to the appropriate DTC inspection.
(See DTC TABLE [L8, LF].)
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No
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Go to the next step.
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2
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Perform the PID/DATA Monitor and Record Procedure and access the ECT PID.
Start the engine and warm it up to ECT PID above 90 °C {194 °F}.
Does the ECT PID increasing dull at thermostat initial operating temperature?
Thermostat initial opening temperature
• 80–84 °C {176–183 °F}
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Yes
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Go to the next step.
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No
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Inspect characteristic of the ECT sensor.
If the ECT sensor has a malfunction:
• Replace the ECT sensor.
If the ECT sensor is normal:
• Replace the thermostat.
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3
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Perform the PID/DATA Monitor and Record Procedure and access the PSP PID.
Does the PID indicate the correct values under 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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Inspect the PSP switch and related wiring harness.
Repair or replace the malfunctioning part according to the inspection results.
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4
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Is the throttle body free of contaminations?
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Yes
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Inspect for air leakage from the intake-air system components while racing 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 diagnostic index to service any additional symptoms.
• If malfunction remains, inspect related Service information perform repair or diagnosis.
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