Unplug the IAC motor harness connector and the MFI relay connector. By touching
the probes of the ohmmeter to both ends of the wiring harness, check for continuity
between the IAC motor terminal 2 and 5 to the MFI relay terminal 5 (3.0L 12
valve engines) or MFI relay terminal 3 (3.0L 24 valve and 3.5L engines). If
no continuity exists, repair the harness between the three terminals.
Unplug the ECM connector, and check for an open or short-circuit to ground
between the ECM terminal and the IAC motor terminals:
3.0L (12 valve) engines:
ECM terminal 58 and IAC motor terminal 1.
ECM terminal 59 and IAC motor terminal 3.
ECM terminal 67 and IAC motor terminal 4.
ECM terminal 68 and IAC motor terminal 6.
3.0L (24 valve) and 3.5L Engines:
ECM terminal 4 and IAC motor terminal 1.
ECM terminal 17 and IAC motor terminal 3.
ECM terminal 5 and IAC motor terminal 4.
ECM terminal 18 and IAC motor terminal 6.
If there is a short or open-circuit, repair the above harnesses, otherwise
the harness is good.
Plug all connectors back into their respective components.
Fig. 1: The harness side connector and terminal numbering — 3.0L
and 3.5L engines
