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Hello, I'm Chris. Thanks for visiting Just Answer.
While the key is in the run position is the (CEL) check engine light on or off?
While cranking is the CEL on or off?
The CEL is on during both tests?
Great, this means the PCM is getting a crank signal. Unplug the ignition coil, turn the key to run, is the Red wire at the coil showing battery voltage?
How exactly are you testing, to verify there is no ignition spark?
Do you own a test light?
Great, unplug the coil, connect your test light to the battery positive wire. Have someone crank the engine while you probe the other 3 pins at the coil connector, not the Red wire. While cranking does the test light flash when testing these 3 wires for a pulsing ground?
Thanks, XXXXX XXXXX verified the crank sensor signal is getting to the computer, and we have verified the coil is getting power. This last test verifies the PCM is not triggering the internal coil ground switches. At the PCM we need to verify its getting all needed powers and grounds, if there good then the PCM is bad. See the below diagrams.
Are you asking where is the PCM?
If it is the PCM itself, then its just like any other computer, one minute working then not the next. Electrical or electronic failures give no warning usually.
The anti theft shuts down the fuel injectors and on some the fuel pump as well. None disable the spark. If there is also a theft issue. The theft light will flash 3 times a second while trying to start.
When you replace the PCM ,you will need to get the replacement programmed to the vehicle before the vehicle will start.