Diesel Data: Automotive Repair

Idle Speed: Testing and Inspection

Idle Speed Inspection

NOTE:
- Before checking the idle speed, check these items:
- The malfunction indicator lamp (MIL) has not been reported on.
- Ignition timing
- Sparkplug
- Air cleaner
- PCV system

- Set the parking brake.

1. Disconnect the evaporative emission (EVAP) canister purge valve connector.




2. Connect the HDS to the data link connector (DLC) (A) located behind the driver's side of the front console.
3. Turn the ignition switch ON (11).
4. Make sure the HDS communicates with the vehicle and the ECM. If it doesn't, Go to the DLC circuit troubleshooting.
5. Start the engine. Hold the engine speed at 3,000 rpm without load (in neutral) until the radiator fan comes on, then let it idle.
6. Check the idle speed without load conditions: headlights, blower fan, radiator fan, and air conditioner off.

Idle speed should be: 900±50 rpm

7. Let the engine idle for 1 minute with high electric load (A/C switch ON, temperature set to max cool, blower fan on high, rear window defogger ON, and headlights on high beam).

Idle speed should be: 900±50 rpm

NOTE: If the idle speed is not within specification, do the ECM idle learn procedure. If the idle is still out of specification, Go to the symptom troubleshooting.

8. Reconnect the EVAP canister purge valve connector.