Test NN - Ignition Diagnostic Monitor (IDM)

To prevent replacement of good components, be aware that the following non-EEC related areas may be at fault: ignition module, ignition coil, spark plugs and/or high tension cables, distributor and PIP sensor.

1. Turn key off and wait 10 seconds. Disconnect E-core ignition connector from coil. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Install breakout box, leaving ECA disconnected. Set DVOM on 200,000-ohm scale. Measure resistance between test pin No. 4 and ignition coil negative terminal. If reading is less than 20,000 ohms or higher than 24,000 ohms, repair open circuit and repeat QUICK TEST  . If reading is between 20,000 and 24,000 ohms, go to next step.
2. Turn key off and wait 10 seconds. Leave breakout box installed and ECA disconnected. With DVOM on 200,000-ohm scale, measure resistance between test pin No. 4 and test pins No. 40, 46, and 60. If any reading is less than 10,000 ohms, repair short to ground and repeat QUICK TEST  . If all readings are 10,000 ohms or more, go to next step.
3. Turn key off and wait 10 seconds. Deactivate SELF-TEST. Using CONTINUOUS MONITOR (WIGGLE) TEST, observe VOM or diagnostic tester for indication of fault while lightly tapping on TFI module and wiggling TFI harness connector. If fault is indicated, disconnect TFI harness. Inspect connector and terminals for damage. If connector and terminals are okay, check TFI ignition system. If no fault is indicated, go to next step.
4. While in CONTINUOUS MONITOR (WIGGLE) TEST, observe VOM or diagnostic tester for indication of fault while wiggling, shaking, or bending small sections of harness while working from TFI connector toward firewall. Repeat process from firewall to ECA. Perform this test to check for faults in the following circuits:
   IDM TEST CIRCUITS
   
   

   Condition	Test Pin
   PIP Open/Shorted to Ground	Check circuit at test pin #56.
   SPOUT Shorted to Ground	Check circuit at test pin #36.
   Ignition Ground Open	Check circuit at test pin #16.
   IDM Open to Ground	Check circuit at test pin #4.
   IDM Shorted to Power	Check circuit at test pin #4.

   Perform CONTINUOUS MONITOR (WIGGLE) TEST on these circuits one at a time in order to isolate fault. If fault is indicated, isolate fault and repair harness. Repeat QUICK TEST  . If no fault is indicated, go to next step.

5. Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion or loose wires. If connector is damaged, repair as necessary and repeat QUICK TEST  . If connector is okay, replace ECA. Start and run engine for one minute. Perform KOER SELF-TEST and observe codes. Connect ECA when step is completed.

Fig 1: IDM Circuit