With Standard Transmission

ENGINE SPEED DIPS WHEN A/C IS SWITCHED ON

Conditions for Fault Tracing:
^ No DTCs present.
^ Engine hot.
^ Fault is permanent.

Fault sources
^ Open-circuit in signal lead from A/C compressor.
^ Faulty Idle Air Control (IAC) Valve.

TESTING PROCEDURE








Checking A/C Compressor Signal
^ START engine and allow to idle.
^ Switch ON A/C.
^ Select fan speed 1.
^ Display and read A/C compressor status.

If A/C compressor is ON:
- Proceed to: Checking IAC Valve Connector.
If A/C compressor is OFF:
- Proceed to: Checking Signal Lead, section below.





Checking IAC Valve Connector
^ Clean and grease IAC valve connector.
^ Check if engine speed still dips.

If speed dips:
- Try with new IAC valve.








Checking Signal Lead
^ Switch OFF ignition.
^ Connect test box to MFI system and check ground terminals.
^ Plug MFI module into test box adapter.
^ Switch ON A/C.
^ Select fan speed 1.
^ START engine.
^ Connect voltmeter across #25 (MFI A25) and #20 (MFI A20) on test box.

Instrument should indicate battery voltage when compressor runs.

If reading is correct:
- Speed dip is due to contact resistance in MFI Control Module connector.
- Clean and grease connector.
If reading is incorrect:
- Check lead between MFI module A25 and pressostat connector (7/53) terminal 2 for open-circuit.