NO.7 SLOW RETURN TO IDLE [L8, LF]

id0103a0801300

7 | SLOW RETURN TO IDLE
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DESCRIPTION | • Engine takes more time than normal to return to idle speed.
POSSIBLE CAUSE | • 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

Diagnostic procedure

STEP | INSPECTION | RESULTS | ACTION
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1 | 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].) (See ON-BOARD DIAGNOSTIC TEST [L8, LF].) Are any DTCs present? | Yes | Go to the appropriate DTC inspection. (See DTC TABLE [L8, LF].)
No | Go to the next step.
2 | Perform the PID/DATA Monitor and Record Procedure and access the ECT PID. (See ON-BOARD DIAGNOSTIC TEST [L8, LF].) 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} | Yes | Go to the next step.
No | Inspect characteristic of the ECT sensor. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION [L8, LF].) If the ECT sensor has a malfunction: • Replace the ECT sensor. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION [L8, LF].) If the ECT sensor is normal: • Replace the thermostat. (See THERMOSTAT REMOVAL/INSTALLATION [L8, LF].)
3 | Perform the PID/DATA Monitor and Record Procedure and access the PSP PID. (See ON-BOARD DIAGNOSTIC TEST [L8, LF].) Does the PID indicate the correct values under trouble condition? | Yes | Go to the next step.
No | Inspect the PSP switch and related wiring harness. (See POWER STEERING PRESSURE (PSP) SWITCH INSPECTION [L8, LF].) Repair or replace the malfunctioning part according to the inspection results.
4 | Is the throttle body free of contaminations? | Yes | 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.
No | Clean or replace the throttle body. (See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION [L8, LF].)
5 | Verify test results. • If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [L8, LF].) • If malfunction remains, inspect related Service information perform repair or diagnosis. ― If vehicle repaired, troubleshooting completed. ― If vehicle not repaired or additional diagnostic information not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [L8, LF].)