13C-IDLE SPEED IS HIGH (IMPROPER IDLE SPEED)

Inspection procedure 8: Idle speed is high (improper idle speed)

COMMENT

In such cases as the above, the cause is probably that the intake air volume during idle is too great.

TROUBLESHOOTING HINTS (The most likely causes for this case:)

Engine coolant temperature sensor signal failed.
Accelerator pedal position sensor (main) signal failed.
Accelerator pedal position sensor (sub) signal failed.
A/C switch signal failed.
Evaporative emission control system failed.
ECM failed.

DIAGNOSIS

Required Special Tool:

MB991958: Scan Tool (M.U.T.-III Sub Assembly)

MB991824: V.C.I.
MB991827: USB Cable
MB991910: Main Harness A

STEP 1. Using scan tool MB991958, read the diagnostic trouble code (DTC).

caution

To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.

(1) Connect scan tool MB991958 to the data link connector.

(2) Turn the ignition switch to the "ON" position.

(3) Read the DTC.

(4) Turn the ignition switch to the "LOCK" (OFF) position.

Is any DTC set?

Refer to, Diagnostic Trouble Code Chart

Go to Step 2.

STEP 2. Using scan tool MB991958, check data list.

(1) Turn the ignition switch to the "ON" position.

(2) Check the following items in the data list. Refer to Data List Reference Table

Item 6: Engine Coolant Temperature Sensor
Item 11: Accelerator Pedal Position Sensor (main)
Item 12: Accelerator Pedal Position Sensor (sub)
Item 76: A/C Switch

(3) Turn the ignition switch to the "LOCK" (OFF) position.

Is the sensor operating properly?

Refer to GROUP 17, Emission Control - Evaporative Emission Control System - Evaporative Emission Purge Solenoid Check

Repair or replace it. Then confirm that the malfunction symptom is eliminated.