Idle Speed: Inspection

WARNING: This page is about a different car, the 2003 Subaru Outback, 2003 Subaru Legacy, and 2003 Subaru Baja. However, it is still accessible from the selected car via links, so may be relevant.

Before checking idle speed, check the following:
1. Ensure that air cleaner element is free from clogging, ignition timing is correct, spark plugs are in good condition, and that hoses are connected properly.
2. Ensure that malfunction indicator light (CHECK ENGINE light) does not illuminate.
Warm-up the engine.
Stop the engine, and turn ignition switch to OFF.
When using SUBARU SELECT MONITOR See SPECIAL TOOLS , PREPARATION TOOL, General Description
1. Insert the cartridge to SUBARU SELECT MONITOR.
2. Connect SUBARU SELECT MONITOR to the data link connector.
  
  Fig 1: Identifying Data Link Connector
  Courtesy of SUBARU OF AMERICA, INC.
3. Turn ignition switch to ON, and SUBARU SELECT MONITOR switch to ON.
4. Select {2. Each System Check} in Main Menu.
5. Select {Engine Control System} in Selection Menu.
6. Select {1. Current Data Display & Save} in Engine Control System Diagnosis.
7. Select {1.12 Data Display} in Data Display Menu.
8. Start the engine, and read engine idle speed.
When using tachometer (Secondary pick-up type).
1. Attach the pick-up clip to No. 1 cylinder spark plug cord.
2. Start the engine, and read engine idle speed.
  
  Fig 2: Checking Engine Idle Speed Using Tachometer
  Courtesy of SUBARU OF AMERICA, INC.
NOTE:
- When using the OBD-II general scan tool, carefully read its operation manual.
- This ignition system provides simultaneous ignition for #1 and #2 plugs. It must be noted that some tachometers may register twice that of actual engine speed.
Check idle speed when unloaded. (With headlights, heater fan, rear defroster, radiator fan, air conditioning, etc. OFF)
Idle speed (No load and gears in neutral (MT), or N or P(AT) position):
1. MT vehicle: 650+/-100 rpm
2. AT vehicle: 700+/-100 rpm
Check idle speed when loaded. (Turn air conditioning switch to "ON" and operate compressor for at least one minute before measurement.)
1. Idle speed [A/C "ON", no load and gears in neutral (MT) or Nor P (AT) position]: 850+/-100 rpm
NOTE: The idle speed is adjusted automatically and manual adjusting cannot be performed. If idle speed is out of specifications, refer to BASIC DIAGNOSTIC PROCEDURES .