Diamante Sedan V6-2972cc 3.0L DOHC (1993)
Oscilloscope Test
2. Idle the engine and observe the pattern when the A/C (or any electrical load) is placed on the engine.
NOTE: Since the IAC motor only operates to change the idle speed, the pattern will only be visible when it operates.
HARNESS TEST
1. Turn the key to the ON position.
2. Disconnect the IAC connector.
3. Using a volt meter, check the voltage between IAC connector harness terminal 2 and ground.
Voltage System voltage.
4. Using a volt meter, check the voltage between IAC connector harness terminal 5 and ground.
Voltage System voltage.
5. Disconnect the ECM and IAC connectors.
6. Using an ohm meter, check for continuity between ECM harness terminal 4 and IAC harness terminal 1.
Continuity Should exist
7. Using an ohm meter, check for continuity between ECM harness terminal 17 and IAC harness terminal 3.
Continuity Should exist
8. Using an ohmmeter, check for continuity between ECM harness terminal 5 and IAC harness terminal 4.
Continuity Should exist
9. Using an ohm meter, check for continuity between ECM harness terminal 18 and IAC harness terminal 6.
Continuity Should exist
10. Using an ohm meter, check for continuity between ECM harness terminal 4 and ground.
Continuity Should not exist
11. Using an ohm meter, check for continuity between ECM harness terminal 17 and ground.
Continuity Should not exist
12. Using an ohm meter, check for continuity between ECM harness terminal 5 and ground.
Continuity Should not exist
13. Using an ohm meter, check for continuity between ECM harness terminal 18 and ground.
Continuity Should not exist
If any of the previous tests produce unsatisfactory results, the harness will need to be repaired or replaced. Once repairs have been completed, road
test the vehicle to confirm that the repair has corrected the problem.
If the same problem reoccurs, it is possible that there is an intermittent failure of the component or the ECM. Check for looseness at all harness
junctions and test for an intermittent failure.
