What's the difference between the PCM and Engine Control Module?

What engine ? could have come with three different one's . 3.9 , 5.2 , or 5.9 l . What is it your looking for ICM - ignition control module ????? It's part of the engine control module . The crankshaft position sensor is a direct input to the PCM - engine computer .

It appears to be located down by oil filter, three wire connector. Take wire connector loose, the sensor should have a mounting bolt, remove the bolt, work the sensor out. I can't guarantee replcing will fix the problem, if not, could be a problem with wiring circuit, some where?

Transmission control module is part of the PCM - powertrain control module . Engine an transmission module all in one . It's in the engine compartment .
Powertrain Control Module (PCM) 4.8L,5.3L,6.0L
Near the left front inside the engine compartment

Only the gauges don't work ? All the warning lights come on when you turn on the key ? ABS , check engine, air bag etc... Have you had the vehicle to a repair shop to have the vehicle checked for DTC'S - diagnostic trouble codes stored in the instrument cluster ? There is a microprocessor inside the instrument cluster an can store DTC'S which have nothing to do with the check engine light . The gauges are controlled by that microprocessor based on information from the PCM ,sent on the class 2 serial data network .

Indicators and Warning Messages
Refer to Indicator/Warning Message Description and Operation .
Engine Coolant Temperature Gage
The instrument panel cluster (IPC) displays the engine coolant temperature as determined by the powertrain control module (PCM). The IPC receives a class 2 message from the PCM indicating the engine coolant temperature. The engine coolant temperature gage defaults to 75°C (160°F) or below when:
• The PCM detects a malfunction in the engine coolant temperature sensor circuit.
• The IPC detects a loss of class 2 communication with the PCM.
Engine Oil Pressure Gage
The instrument panel cluster (IPC) displays the engine oil pressure as determined by the powertrain control module (PCM). The IPC receives a class 2 message from the PCM indicating the engine oil pressure. The engine oil pressure gage defaults to 0 kPa (0 psi) or below if:
• The PCM detects a malfunction in the engine oil pressure sensor circuit.
• The IPC detects a loss of class 2 communications with the PCM.
Fuel Gage
The instrument panel cluster (IPC) displays the fuel level as determined by the powertrain control module (PCM). The IPC receives a class 2 message from the PCM indicating the fuel level percent. The fuel gage defaults to empty if:
• The PCM detects a malfunction in the fuel level sensor circuit.
• The IPC detects a loss of class 2 communications with the PCM.
When the fuel level is less than a pre-determined value, the low fuel indicator illuminates.
Reviewing the fuel system description will further explain how the system functions. Refer to:
• Fuel System Description in Engine Controls - 4.8L, 5.3L and 6.0L
• Fuel System Description in Engine Controls - 8.1L

There are also U codes , communication failure's DTC U1000 and U1255

Circuit Description
Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. When a module receives a message for a critical operating parameter, the module records the identification number of the module which sent the message for State of Health monitoring. A critical operating parameter is one which, when not received, requires that the module use a default value for that parameter. When a module does not associate an identification number with at least one critical parameter within about five seconds of beginning serial data communication, DTC U1000 or U1255 is set. When more than one critical parameter does not have an identification number associated with it, the DTC will only be reported once. The class 2 serial data line on this vehicle is a ring/star configuration. The following modules communicate on the class 2 serial data line:
• The body control module (BCM)
• The digital audio broadcast (DAB) module
• The digital radio reciever
• The driver door module (DDM)
• The electronic brake control module (EBCM)
• The front passenger door module (FPDM)
• The HVAC control module
• The HVAC control module-rear auxilliary
• The inflatable restraint sensing and diagnostic module (SDM)
• The instrument panel cluster (IPC)
• The memory seat module (MSM)
• The powertrain control module (PCM)
• The radio
• The radio amplifier
• The rear seat audio (RSA) controller
• The rear seat entertainment (RSE) assembly w/U42
• The rear wheel steering control module
• The remote playback device-CD player w/U1S
• The suspension control module
• The transfer case shift control module
• The transmission control module (TCM) w/allison transmission
• The theft deterrent control module
• The vehicle communication interface module (VCIM) w/UE1

Your best bet would be to take it to a qualified repair shop .

Do you mean the transmission control module ? It is incorporated into the engine control module . PCM - powertrain control module .

Powertrain Control Module (PCM) (L36/L67)
Left front of the engine compartment, inside the air cleaner assembly
Engine Controls Component Views in Engine Controls - 3.8L
Powertrain Control Module Connector End Views in Engine Controls - 3.8L
Powertrain Control Module (PCM) (LG8)
Left front of the engine compartment, inside the air cleaner assembly

The onboard computer, or Powertrain Control Module (PCM),is the brains of the engine control system, so when the brain is not functioning correctly neither is the engine or anything else that the microprocessor controls - which may include the charging system, transmission, various emission controls and communications with other onboard control modules. Once a diagnosis has been made (and we emphasize the word diagnosis), then and only then should the PCM be replaced.
P0600....Serial Communication Link

P0601....Internal Control Module Memory Check Sum Error

P0602....Control Module Programming Error

P0603....Internal Control Module Keep Alive Memory (KAM) Error

P0604....Internal Control Module Random Access Memory (RAM) Error

P0605....Internal Control Module Read Only Memory (ROM) Error

P0606....ECM/PCM Processor

P0607....Control Module Performance

P0608....Control Module VSS Output 'A'

P0609....Control Module VSS Output 'B'

P0610....Control Module Vehicle Options Error

If you see any of these codes when diagnosing the vehicle with a code reader or scan tool, it may mean the PCM has failed and must be replaced. Additional diagnostic tests will usually be necessary to confirm the problem is really the powertrain control module and NOT something else. Refer to the OEM diagnostic charts for what these tests are. Usually it involves checking certain inputs to the PCM to see if it outputs the correct response. No response or an incorrect response usually means the PCM is defective and needs to be replaced.
All too often, technicians tend to blame that which they understand least. If an engine is not running right and the cause is not obvious, they may blame the computer. Throwing parts at a problem in an attempt to solve it may be good for the parts business, but when a customer brings a PCM back because it failed to fix their problem, nobody wins. Warranty returns on complicated and expensive components like powertrain control modules are an ongoing problem that costs everyone money.
UNNECESSARY POWERTRAIN CONTROL MODULE RETURNS. Over 50 percent of PCMs that are returned under warranty (either because the PCM failed to fix a performance problem or because the engine did not run properly after it was installed) have nothing wrong with them! So it is obvious a lot of people are swapping computers to see if a different PCM will fix their problem.
The trouble with returns is if the PCM has been on the car, you have no way of knowing if it is still "good" or not. Somebody may have crossed up some wires, zapped the PCM with too much voltage or who knows what? The computer needs to be tested and verified before it can go back on the shelf and be sold to somebody else.
Unfortunately, there is no easy way of doing that in a parts store. The PCM has to be hooked up to a sophisticated simulator that exercises all of the computer's input and output circuits to make sure it works correctly - which means the PCM has to go back to the supplier, be retested, and if no fault is found, repackaged and put back into stock.
Be warned, though, that many parts stores have a policy of "no returns or refunds on electronic components."

(PCM) Powertain Control Module

Before PCM--the (EEC) Electronic Engine Control Processor

Other mfg use different terms

That is your main processor, people like to call a computer

There are several others, on most vehicles since 1996 on

The PCM is located behind the engine on the passenger side of the car, it is in a slot in the fire wall behind the cowl cover. here is Fords instructions for replacing it.Powertrain Control Module (PCM)
Removal

Disconnect battery ground cable (14301) . Refer to Section 14-01.

Remove cowl deflector.

Remove screw securing the ground cable of the engine control sensor wiring (12A581) to the dash panel (01610) .

Loosen engine control sensor wiring to PCM connector retainer bolt.

Remove engine control sensor wiring from PCM (12A650) .

Remove retaining nuts and powertrain control module insulator from dash panel .

Remove powertrain control module .

Installation

Follow removal procedure in reverse order.

Tighten insulator retaining nuts to 8-12 Nm (71-106 lb-in).

Tighten engine control sensor wiring retainer bolt to 3.7 Nm (33 lb-in).

Tighten engine control sensor wiring ground retaining screw securely.

The onboard computer, or Powertrain Control Module (PCM),is the brains of the engine control system, so when the brain is not functioning correctly neither is the engine or anything else that the microprocessor controls - which may include the charging system, transmission, various emission controls and communications with other onboard control modules. Once a diagnosis has been made (and we emphasize the word diagnosis), then and only then should the PCM be replaced. It could be something as simple as the throttle position sensor, O2Sensor, etc. But knowing for sure could save a lot of time and money. The resetting (relearning process can be problematic in ways like causing car alarm problems, etc.
You can try unhooking the battery for about 15 minutes and see if it will reset the module but it's not likely. It could be many, many things so you really should have it diagnosed
Onboard Diagnostic (OBD II) diagnostic trouble codes that typically indicate a fault with the powertrain control module include:

P0600....Serial Communication Link

P0601....Internal Control Module Memory Check Sum Error

P0602....Control Module Programming Error

P0603....Internal Control Module Keep Alive Memory (KAM) Error

P0604....Internal Control Module Random Access Memory (RAM) Error

P0605....Internal Control Module Read Only Memory (ROM) Error

P0606....ECM/PCM Processor

P0607....Control Module Performance

P0608....Control Module VSS Output 'A'

P0609....Control Module VSS Output 'B'

P0610....Control Module Vehicle Options Error


If you see any of these codes when diagnosing the vehicle with a code reader or scan tool, it may mean the PCM has failed and must be replaced. Additional diagnostic tests will usually be necessary to confirm the problem is really the powertrain control module and NOT something else.
All too often, technicians tend to blame that which they understand least. If an engine is not running right and the cause is not obvious, they may blame the computer. Throwing parts at a problem in an attempt to solve it may be good for the parts business, but when a customer brings a PCM back because it failed to fix their problem, nobody wins. Warranty returns on complicated and expensive components like powertrain control modules are an ongoing problem that costs everyone money.
UNNECESSARY POWERTRAIN CONTROL MODULE RETURNS. Over 50 percent of PCMs that are returned under warranty (either because the PCM failed to fix a performance problem or because the engine did not run properly after it was installed) have nothing wrong with them! So it is obvious a lot of people are swapping computers to see if a different PCM will fix their problem.
Unfortunately, there is no easy way of doing that in a parts store. Be warned, though, that many parts stores have a policy of "no returns or refunds on electronic components."
PCMs typically fail for one of two reasons: voltage overloads (often due to a short in a solenoid or actuator circuit) or environmental factors (corrosion, thermal stress or vibration). If the shorted solenoid or actuator is not found and repaired, the voltage overload it creates may damage the replacement PCM, too.
As for environmental factors, water is the main thing to avoid. If water gets inside a PCM, it can short circuits and set up irreversible corrosion that ruins electronic connections. Most remanufacturers will not even attempt to repair a PCM if the vehicle it came out of was submerged in a flood. Replacement is the only option. Thermal stress and vibration can form microcracks in circuit boards (which are repairable). This often has more to due with the ruggedness of the circuit design than operation factors in the vehicle itself.
ACCURATE POWERTRAIN CONTROL MODULE IDENTIFICATION
Because there are so many different PCMs, accurate identification of the PCM and its correct replacement is absolutely essential to prevent unnecessary returns. Many PCMs appear to be exactly the same on the outside (same sized box and connectors) but may be wired or calibrated differently inside.
Accurately identifying the PCM requires not only the vehicle year, make, model and engine size, but also the OEM part number on the PCM itself. Most supplier catalogs list replacement PCMs both ways. So if in doubt, always refer to the OEM number on the PCM and look it up in the suppliers cross reference index to find their replacement part number.
The calibration chip and PROM contains the programming instructions for the vehicle application. That is why it usually does not come with the replacement PCM. There are too many different possibilities. On many newer vehicles, flash memory or "EEPROMs" (Electronically Erasable Program Read Only Memory) are used. If the replacement PROM is not properly programmed for the application, it must be reprogrammed after it has been installed.

Unfortunately, the ability to do this type of reprogramming is not readily available to the aftermarket. The car makers do not want aftermarket technicians messing around with the calibration of their onboard computers because they are afraid doing so may alter emissions or performance. But that is another issue. One such example is Chrysler transmission modules. They must be reset with the factory DRB scan tool and dealer codes to set the "pinion factor," which controls the operation of the speedometer.

REMAN POWERTRAIN CONTROL MODULES

Because a powertrain control module can be very expensive to replace, almost all aftermarket replacement PCMs are "remanufactured" units. A PCM is not rebuilt in the same way that an alternator or water pump is rebuilt because there are no mechanical parts that wear out. Remanufacturing in this case usually means testing the powertrain control module, isolating and repairing any faults that may be found, then retesting the powert5ain control module to make sure everything works correctly.

A remanufactured PCM is typically sold one of two ways: on an exchange basis from stock, or on a custom rebuild basis. If a particular PCM is not in stock or is unavailable, you may be able to send an old PCM to a remanufacturer for repair. Turn around time is typically a few days and the cost is about the same as an exchange unit except there is no core charge). The hard part is finding a remanufacturer who can test and repair your powertrain control module.

Some PCMs, though, may not be repairable. As we said earlier, most remanufacturers will not even touch a PCM if it came out of a flooded vehicle.

PCM REPLACEMENT TIPS

Replacing a PCM is essentially a matter of swapping boxes. Accessibility can be a problem on some vehicles because the PCM is often buried under or behind other components in the instrument panel, climate control system or console. Some are located under a seat and require removing the seat.

Regardless of the PCM's location, though, one thing you should do prior to removing the old PCM and installing the replacement PCM is disconnect the battery.



On some applications, there may be a specific relearn procedure for establishing the base idle speed and other operating parameters. On others, it may be necessary to take the vehicle for a short test drive so the computer can adjust itself. The exact requirements will be spelled out in the vehicle service manual. The best advice here is to test drive the vehicle after the powertrain control module has been installed. A short drive cycle that includes going over 35 mph will usually reset most PCMs so they will operate properly.
The powertrain control module will also continue to learn and make small adjustments to the fuel mixture and other functions over time as the vehicle accumulates miles. If the PCM also controls the transmission, it may take awhile to relearn the driver's habits so the transmission may not shift exactly the same as before until this occurs.



If the engine control system is not going into closed loop, chances are the coolant sensor or oxygen sensor may not be working properly. If spark timing seems to be over advanced or retarded, the problem may be a faulty MAP sensor, misadjusted throttle position sensor or overly sensitive knock sensor. And if nothing seems to work right, low charging voltage due to a weak alternator or poor battery connections may be the fault.

Remember, a powertrain control module needs all its sensor inputs, proper battery voltage, a good ground and the ability to send out control signals to function normally.
Good luck
If this helps you resolve your problem, please
consider giving me a good rating and a quick
thanks or good job.It will help me as well.
Thank you.