yo,
YW!
Ford went from two-digit to three-digit EEC IV Self-Test codes in 1991 to service the increasing number of service codes required to support various government On-Board Diagnostic (OBD) regulations. The phase-in from two-digit to three-digit codes started in the 1991 model year and is largely complete except for some medium/heavy trucks that will retain two digit codes through the 1994 model year.
Miesk5 NOTE; use BLACK CCD Ignition Modules in 94-96 Broncos
Here is more info on the correct ICM module by a pal who knows Ford EEC;
"I've done a LOT of research on this in the past few months. It turns out that indeed, Ford turned to a CCD (computer-controlled dwell) ignition module sometime between 1993 and 1995. I only found this out because, like you, I got the code 212 along with some ignition problems. Well, that and Steve83 and I had slight disagreement; I'd incorrectly assumed the parts catalogs to be correct, whereas his recollection was based upon Ford's schematics. Now I only trust the OE schematics and OE part numbers. I've bugged the local Ford dealer's parts people to DEATH over some stupid things like this.
I'll let you read this Standard Tech Tips article to give you a better idea of the difference, how to tell which you have, and what to do about it:
Originally Posted by Standard Motor Corporation
FORD- IDM FAULT CODES AFTER MODULE REPLACEMENT
If you run across a Ford vehicle that has an IDM (Ignition Diagnostic Monitor) fault code, this tip may be helpful.
The TFI module (Thick Film Integration, which refers to the type of internal circuitry used in this module) has been used on the EEC-IV system since its inception. There are two different module types, and, even though they may look alike, they are not interchangeable.
One type is referred to as the "Push Start" type, while the other is called the "CCD" (Computer Controlled Dwell) type. The "Push Start" module gets its name from the 4th pin on the module connector, which is a start signal inputfrom the starting system. When the module receives this 12 volt input, it increases or "Pushes" he ignition coil dwell for maximum coil output for easier starting. The "CCD" module does not use a start signal input, but does rely upon the ECM Spout input to control ignition coil primary dwell. By the way, ECM Spout controls ignition timing on both module systems.
Under normal running conditions, the "Push Start" module starts the ignition coil primary dwell time about 3.5 milliseconds before then next anticipated coil firing. At this point the module is waiting to see the Spout signal voltage change from low to high. When this happens, current flow to the coil is stopped, which will result in the coil firing. If the time is longer than 3.5 milliseconds, the module will reduce the primary current to prevent the coil from overheating, since it cannot anticipate the next coil firing. The "CCD" module relies solely on the ECM Spout input to change ignition coil primary dwell time. On this system, the trailing edge of the Spout wave will start the primary cycle, while the leading edge of the next wave will end it, resulting in the coil firing. The time in between signals is the dwell.
Both modules are used in systems where they may be mounted on the distributor, or, they may be remotely mounted away from the distributor (commonly called "Closed Bowl" versions). Usually, the "Push Start" modules are gray in color, while the "CCD" modules are black.
IDM is a feedback signal generated by the ignition system and is monitored at pin #4 of the ECM. Its purpose is to diagnose missed ignition primary pulses at the time the ECM commands the Spout signal to fire the coil. Since it is used solely for diagnostic purposes, if this circuit is not operating properly, it will not affect vehicle driveability.
Both "Push Start" and "CCD" systems produce an "IDM" signal, however, they do it in different ways. The "Push Start" system uses an external 22K ohm resistor (22,000 ohms) that is usually taped to the wiring harness that is connected to the negative terminal of the ignition coil. [On our trucks, it is usually located in the harness between the engine and the driver's side fender] This resistor is used to lower the voltage of the Tach signal being supplied to pin #4 of the ECM.
This external resistor is not used on the CCD system since it is part of the internal circuitry of the module, which produces the IDM signal. So, the IDM signal travels from pin #4 of the module directly to pin #4 of the ECM.
Oddly enough, the "Start" pin on the "Push Start" module is the same pin as the IDM pin on the "CCD" module. While the connectors are identical, interchanging the modules may or may not create a driveability problem, while tripping a fault code of #18, or # 212 (IDM code). These are problems consistent with interchanging one type module in place of the other.
Identifying the correct module for your vehicle can be accomplished in a number of ways. First, always refer to the correct application in the Engine Management catalog. If that information is not available, check the wiring of the vehicle. If pin # 4 of the module gets a start signal (which should be battery voltage) from the starter circuit, it's a "Push Start" system. On the other hand, if pin #4 of the module is wired directly to pin #4 of the ECM, then it's a CCD system (refer to diagram #5).
So, if your original TFI ignition module was black, the auto parts store more than likely sold you the wrong one. This is because ALMOST ALL of the parts stores' catalogs are WRONG. They all list the "push-start" type of module, NOT the correct CCD. I guess asking whether the original module was black or gray was too much trouble for the shitbags writing the catalogs; instead, they just plagiarized someone else's erred work.
Like the article says, you'll have to do some checking if you don't remember whether your original module was black or gray. Check the voltage on the TFI connector's #4 pin during cranking. A steady +12V signal during cranking means it's the older push-start (as outlined in the article). If it goes directly to the #4 pin on the PCM, it's a CCD.
Here's the F'ed up part: try asking for a CCD TFI ignition module in a parts store.
Not to worry. The Wells part number is F139, Niehoff's is FF413, BWD is CBE40, and Standard's number is LX-241, if that helps. Even Motorcraft's catalog was superseded by the push-start module; I guess Ford doesn't particularly care whether your diagnostic systems are working properly or not.
An alternative is to look up the ignition module for a 1994-1995 Mustang GT. These should also have the same, remote-mounted CCD modules the later Broncos should have. In this application, the Motorcraft part number is DY1077, with OE numbers: {#5U2Z-12A297-D, DY679, or F1PZ-12A297-A}.
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SigEpBlue
