1994 Ford Mustang Trouble code 212 how to fix

almtyscuzzy · Posted at Thu Jul 02, 2009 6:17 pm

Electrical problem
1994 Ford Mustang V8 Two Wheel Drive Manual 100,00 miles

This code 212 is driving me crazy, can't seem to fix it. I followed the procedure below along with my findings. My answer is after each procedure.

3) Check IDM Circuit Continuity

Turn ignition off. Disconnect 60-pin PCM connector. Inspect connector for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Disconnect ICM. Measure resistance between test pin No. 4 at breakout box and IDM circuit terminal at ICM wiring harness connector. If resistance is less than 5 ohms, go to step 5). If resistance is 5 ohms or more, repair open circuit, and repeat QUICK TEST . (I got 0.5 ohms)

NOTE:A break in step numbering sequence occurs at this point. Procedure skips from step 3) to step 5). No test procedures have been omitted.

5) Check IDM Circuit For Short To Power (Except VREF)

Turn ignition off. Leave ICM and PCM disconnected. Measure voltage between breakout box test pin No. 4 and negative battery terminal. Turn ignition on. Measure voltage between test pin No. 4 and test pins No. 40 and 60 at breakout box. If any reading is more than 10.5 volts, repair short circuit. Clear codes, and repeat QUICK TEST . If both readings are 10.5 volts or less, go to next step. (I got 0vdc is this correct.)

6) Check IDM Circuit For Short To PIP & VREF

Turn ignition off. Leave PCM and ICM disconnected. Remove scan tool (if applicable). For shorts to PIP, measure resistance between test pins No. 4 and No. 56 at breakout box. For shorts to VREF, measure resistance between test pins No. 4 and No. 26 at breakout box. If either resistance is 10,000 ohms or less, repair short circuit. Remove breakout box, reconnect all components, and repeat QUICK TEST . If each resistance is more than 10,000 ohms, go to next step. (I got an open here or infinite resistance)

7) Check IDM Circuit For Short To Ground

Turn ignition off. Leave ICM and PCM disconnected. Measure resistance between test pin No. 4 and test pins No. 20, 40, 46 and 60 at breakout box. If each resistance is more than 10,000 ohms, go to next step. If any resistance is 10,000 ohms or less, repair short to ground in IDM circuit. Remove breakout box, reconnect all components, and repeat QUICK TEST .
Check ICM . I got no resistance or infinite resistance)

8)Turn ignition off. Connect PCM to breakout box. Reconnect ICM to wiring harness connector. Connect DVOM between test pins No. 4 and 16 at breakout box. Start engine. Observe DVOM for voltage surge while lightly tapping on ICM and Camshaft Position (CMP) sensor (if equipped) to simulate road shock. Wiggle all ICM and CMP sensor wiring and harness connectors. If fault (voltage surge) is not indicated, go to next step. If fault (voltage surge) is indicated, disconnect and inspect wiring harness connectors and terminals for damage. Repair as necessary. If connectors and terminals are okay, check ignition system. See the I - SYSTEM/COMPONENT TESTS - EEC-IV (5.0L) article.
9) Check PCM & Harness Connectors

Ensure engine is still running and DVOM is still connected between test pins No. 4 and 16 at breakout box. While observing DVOM, wiggle and bend wiring harness, a small section at a time, from ICM and CMP sensor (if equipped) to cowl. Also, check harness from cowl to PCM. If fault is indicated, isolate fault and repair as necessary. Remove breakout box, reconnect all components, and repeat QUICK TEST . If no fault is found, go to next step.
My voltage moved from 12.45 vdc to 12.26 or a little hiher like 12,56 but I am using a big aftermarket camshaft.

10) Check PCM & Harness Connectors

Turn ignition off. Disconnect PCM 60-pin connector. Inspect connector for damaged pins, corrosion and loose wires. Repair as necessary. If connector is damaged, repair as necessary. Remove breakout box, reconnect all components, and repeat QUICK TEST . If connector is okay, go to next step.
Connector looks fine.

jnovack · Posted at Thu Jul 02, 2009 6:59 pm

I would first inspect the SPOUT connector that is by the distributor. It is a single harness that has a plug at the end of it. Perhaps it is missing this plug and the computer is not advancing the timing and producing this error. My book also says it is "Loss of Ignition Diagnostic Monitor (IDM).
after you check to see if your spout is there..........i would go ahead and check your engine timing.........remember to do this with the spout removed........once you know your timing is set, shut off the vehicle and check all of your connections around the distributor.....like the harness that goes to the tfi, which sits on the side of your dist....be sure all of your wires at the coil are clean too.........i usually clean the connections, then use dielectric grease on the connections before i install everything back

almtyscuzzy · Posted at Thu Jul 02, 2009 7:04 pm

The spout connector is there and I checked it and it has continunity. I also checked the wires from the spout connector and they do trace back to TFI module and the computer (EEC-IV). So no breaks there.

Timing is fine. with this code 212 what am I looking for? A short somehwere?