Upper Limit

Checking Throttle Body
- Ignition OFF.
- Check that seal on throttle body (TB) adjusting screw is not broken.
- Is seal intact?

No:
^ Proceed to: Checking the Air Cleaner and Air Intake section below.

Yes:
^ Replace throttle body.
^ Proceed to: Verification section below.





Checking the Air Cleaner and Air Intake
- Ignition OFF.
- Check that the air cleaner, air intake and hoses and pipes between the air cleaner and throttle body are not blocked.
- Check idle air control (IAC) valve terminals.

If reading is OK:
^ Proceed to: Checking Idle Air Control Valve section below.

If reading is incorrect:
^ Remedy as necessary.
^ Proceed to: Verification section below.





Checking Idle Air Control Valve
- Ignition OFF.
- Disconnect idle air control valve.
- Connect an ohmmeter between idle air control valve terminals 1 and 3.
- The ohmmeter should read 18 - 28 ohms at +20°C (+68°F).

If reading is OK:
^ Proceed to: Checking the Idle Air Control Valve Control Slide section below.

If reading is incorrect:
^ Try a new idle air control valve.
^ Proceed to: Verification section below.





Checking the Idle Air Control Valve Control Slide
- Ignition OFF.
- Remove idle air control valve.
- Hold the valve by the connector, twist the valve rapidly but carefully back and forth. Listen for the sound of the slide switching.

CAUTION: Under no circumstances touch the slide with a screwdriver or other tool, as this may scratch and damage the slide.

- Is the idle air control valve control slide switching?

Yes:
^ Check idle air control valve and engine control module (ECM) connectors for contact resistance and oxidation and remedy.
^ Proceed to: Verification section below.

No:
^ Try a new idle air control valve.
^ Proceed to: Verification section below.





Verification
After carrying out the repair, check that the fault has been remedied as follows:

- Ignition ON.
- Throttle position (TP) sensor and engine control module connected.
- Ignition ON.
- Erase all adaptive functions but the flywheel.
- Start the engine and run it until it reaches operating temperature, at least 85°C (185°F).
- Engine idling.
- When the idle air trim adaption value has stabilized. Rev the engine to approx. 2,000 rpm and idle it.
- Wait approx. 30 seconds and read off the value again. Repeat this until the value is stable.
- The value should be between -6 and +15 kg/h (-2.7 and +6.8 lb/h).

If reading is OK:
^ Fault corrected.

If reading is incorrect:
^ Proceed to: Diagnostic Trouble Code Information section below.

Diagnostic Trouble Code Information
The verification result shows that the fault persists.

- Do you want to exit fault-tracing?

Yes:
^ Fault not corrected.

No:
^ Proceed to: Checking Throttle Body section above.