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Roy, import/domestic specialest
Category: Car
Satisfied Customers: 4459
Experience:  ASE master tech for 40 years
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Ford LTD Crown Vic: identify what caused ECM to fail

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How do you identify and isolate a bad component in the ignition circuitry that caused the ECM to go bad before you install a replacement ECM?

good morning my name is XXXXX XXXXX I will assist you today

lets do some basic checks first as I do not believe the ecm is your issue with no spark.

first, make sure the rotor in the distributor is turning when cranking.
use a test light and check for power to the ignition coil with the key on. the positive will light the test light as well as the negative side. now, while cranking, probe the negative side to see if the light pulses or flickers. if it does, then the module is working, if not, then it may be a bad distributor pick up or module failure.

do this test first.

as far as checking the ecm, there is a connector chart with your instructions that tell you which terminals to check with an ohm meter for the solenoids. solenoid failure is the primary reason for ecm failures.

Customer: replied 3 years ago.

We have already checked the rotor and probed the ignition coil and confirmed there is power there. We think we isolated the problem to the ECM. There is no chart of the connector with terminals or resistance indicated in the instructions. That is what I was asking about. The instructions say that you should use an ohm meter to identify which components might have caused the overcurrent that damaged the ECM, and repair or replace them, or else it could fry the replacement ECM when it is installed. I just need to know which terminals on the ECM connector to check to each other or to ground to identify the bad component and what the normal resistance range to expect if the component is good, or what to expect if the component has shorted, or is open. Thanks for your assistance.

ok, I will attach the connector view for you. Roy

Roy and 7 other Car Specialists are ready to help you
Customer: replied 3 years ago.

Thanks, XXXXX XXXXX what I need. However, the disclaimer on the chart says don't direct probe the 60 pin connector, use a "Breakout Box". What is this, and where do I get one?



breakout box is a tool that is around 2500 bucks.

remove the connector from the ecm and probe from the front terminals. you will be ok.

how are you making out??

dont forget to hit the smiley button so I get credit for my answers


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