Signal Too Low. Permanent Fault

Checking Power Cable
- Ignition off.
- Disconnect idle air control (IAC) valve.
- Ignition on.
- Connect a voltmeter between idle air control valve connector terminal 2 and ground.
- The voltmeter should read battery voltage.

If reading is OK:
^ Proceed to test step below.

If reading is incorrect:
^ Check cable between main relay (2/32) terminal 3 and idle air control valve terminal 2 for an open-circuit.
^ If there is an open-circuit in the power cable, diagnostic trouble codes (DTCs) EFI-223 and EFI-245 are stored.
^ Then proceed to Verification section below.





Checking Signal Wiring Resistance
- Ignition off.
- Wait for approx. 150 seconds (cars with immobilizer 245 seconds).
- Idle air control valve disconnected.
- Connect an ohmmeter between idle air control valve connector terminals 1 and 3.
- The ohmmeter should read 20 - 40 k ohms.

If reading is OK:
^ Proceed to test step below.

If reading is 0 ohms:
^ Check the cable between the idle air control valve terminal 3 and engine control module (ECM) # A11 for a short-circuit to the cable between idle air control valve terminal 1 and engine control module # A25.
^ Then proceed to Verification section below.

If reading is 10 - 20 k ohms:
^ Check cable between idle air control valve terminal 1 and engine control module # A25 for a short-circuit to ground.
^ Then proceed to Verification section below.





Checking Idle Air Control Valve
- Ignition off.
- Idle air control valve disconnected.
- Connect an ohmmeter between idle air control valve connector terminals 1 and 2.
- Read off value.
- Then connect an ohmmeter between idle air control valve connector terminals 2 and 3.
- Read off value.
- The ohmmeter should read 9 - 14 ohms at +20°C in both cases.

If reading is OK:
^ The diagnostic trouble code has been caused by poor contact in the idle air control valve connector. Check connector for contact resistance and oxidation and remedy.
^ Then proceed to Verification section below.

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





Verification
- After carrying out the repair, check that the fault has been remedied as follows.
- Ignition on.
- Activate idle air control valve.
- A "clicking sound" is heard from the idle air control valve when it is activated.
- Is the idle air control valve working?

If reading is OK:
^ Fault corrected

If reading is incorrect:
^ Proceed to test step below.

Fault-tracing Information
The verification result shows that the fault persists.

- Do you want to exit fault-tracing?

Yes:
^ Fault not corrected

No:
^ Return to Checking Power Cable section above.