Diagnostic Aids

Perform this test when directed by QUICK TEST . This test is only intended to diagnose EEC-IV portion of ignition system. For additional information on ignition system and component testing, see I - SYS/COMP TESTS article in the ENGINE PERFORMANCE Section. To prevent replacing good components, be aware following non-EEC related areas may be at fault:

EDIS ignition module.
EDIS coil packs.
Spark plugs and/or wires.
Variable reluctance sensor.
Secondary ignition short to ground.

This test is intended to diagnose:

IDM and SAW harness circuits.
ECA assembly.

Fig 1: IDM Schematic (1.9L)

Fig 2: IDM Schematic (Crown Victoria, Grand Marquis & Town Car)

1) Continuous Memory Code 211: Erratic Ignition Code 211 indicates 2 successive erratic Profile Ignition Pick-Up (PIP) pulses occurred. Possible causes for this fault are:

Loose wires or connectors.
Secondary ignition short to ground.
On-board transmitter equipment (2-way radio).

Repair any problems found as necessary. Clear codes, and repeat QUICK TEST . If problem is not found, go to step 4).

2) Code 226: IDM Circuit Failure Code 226 indicates ECA did not receive IDM signal from EDIS module in KOEO SELF-TEST . Possible causes for this problem are:

Open or short in IDM or IGN GND circuit wiring harness.
Faulty EDIS module.

If engine does not start, go to IGNITION SYSTEMS in SYSTEM & COMPONENT TESTING - EEC-IV. If engine starts, go to step 4).

3) Continuous Memory Code 212: Check For Other Codes Code 212 indicates loss of IDM input signal to ECA. Possible causes for this fault are:

Open or short circuit in wiring harness.
Faulty EDIS module.
Faulty ECA.

If Continuous Memory Code 215, 216 or 217 is also present, go to IGNITION SYSTEMS in I - SYS/COMP TESTS article in the ENGINE PERFORMANCE Section. If Code 215, 216 or 217 is not also present, go to step 4).

4) Continuous Memory Code 212: Check IDM Circuit Continuity Turn ignition off. Disconnect EDIS module. Disconnect 60-pin ECA connector. Inspect terminals, and repair if damaged. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving ECA disconnected. Measure resistance between test pin No. 4 at breakout box and pin No. 2 at EDIS module wiring harness connector. If resistance is 5 ohms or more, repair open circuit. Clear codes, and repeat QUICK TEST . If resistance is less than 5 ohms, go to step 5).

5) Check IDM Circuit For Short To Power (Except VREF) Turn ignition off. Ensure ECA and EDIS module are disconnected. Monitor circuit voltage by connecting DVOM between test pin No. 4 and test pins No. 40 and 60. To check VBAT circuit, turn ignition off. To check VPWR circuit, turn ignition on. If either voltage reading is more than 10.5 volts, repair short circuit and repeat QUICK TEST . If voltage is 10.5 volts or less, go to step 6).

6) Check IDM Circuit For Short To VREF & PIP Turn ignition off. Ensure ECA and EDIS module are disconnected. To check for shorts to VREF, use DVOM to measure resistance between test pins No. 4 and 26 at breakout box. To test for shorts to PIP, measure resistance between test pins No. 4 and 56 at breakout box. If either resistance is 10,000 ohms or less, repair short circuit and repeat QUICK TEST . If each resistance is more than 10,000 ohms, go to step 7).

When 4-wire HEGO is connected to vehicle harness, a short to SIG RTN (pin No. 46) may be indicated along with an actual short to PWR GND.

7) Check IDM Circuit For Short To Ground Turn ignition off. Ensure ECA and EDIS module are disconnected. Measure resistance between test pin No. 4 and test pins No. 40, 46 and 60 at breakout box. If any reading is less than 10,000 ohms, repair short to ground in IDM circuit. Clear codes, and repeat QUICK TEST . If all resistances are 10,000 ohms or more, go to step 8).

8) Check EDIS Module Turn ignition off. Connect EDIS module to wiring harness connector. Connect ECA to breakout box. Start engine, and allow it to idle. Connect positive lead of DVOM to test pin No. 4 and negative lead to test pin No. 16. Observe DVOM for voltage surge (fault) while lightly tapping on ignition components to simulate road shock. Wiggle all EDIS harness connectors. If fault is not indicated, disconnect and inspect EDIS wiring harness connectors and terminals for damage. If connectors and terminals are okay, check ignition system. See I - SYS/COMP TESTS article in the ENGINE PERFORMANCE Section. If fault is indicated, leave DVOM connected to breakout box and go to step 9).

9) Check EEC-IV Harness Ensure engine is idling at correct RPM. Wiggle, shake or bend small sections of harness, working from DIS connectors to firewall. Observe DVOM for indication of fault. Repeat process from firewall to ECA. If fault is indicated, isolate fault and repair wiring harness. Repeat QUICK TEST . If no fault is indicated, go to step 10).

10) Check ECA & Harness Connectors Turn ignition off. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion and loose wires. If connector is damaged, repair as necessary. Clear codes, and repeat QUICK TEST . If connector is okay, go to step 11).

11) Check ECA For Short To Ground Turn ignition off. Disconnect EDIS module connector. Connect ECA to breakout box. Measure resistance between test pin No. 4 and test pins No. 16, 20, 40, 46 and 60. If each resistance is more than 10,000 ohms, check ignition system. See I - SYS/COMP TESTS article in the ENGINE PERFORMANCE Section. If any resistance is 10,000 ohms or less, replace ECA and repeat QUICK TEST .