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2001 Trooper ECU for manual transmission

7695 Views 256 Replies 6 Participants Last post by  lordcolemanresearch
I stupidly fried my ECU by forgetting to disconnect the negative battery cable while installing a power antenna. I sent if off for repair and it was returned as "not repairable. Anyone have a 8093935190 ECU? Please respond here or email at [email protected].
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00-02 Trooper use the same Powertrain Control Module (PCM) "ECU"
You can use an auto transmission PCM which is a lot easier to find to get you back on the road while you search out the hard to find manual transmission version. Be aware that if you use an auto transmission PCM the CEL will constantly be illuminated because the PCM thinks there are transmission electrical problems.
There is no requirement to reprogram a used 00-02 Trooper PCM, it is plug and play.
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I would guess that for most repairs there would be no need to reprogram the unit. One thing I am sure of is the ECU/ECM/PCM used in the Isuzu's seldom fail. I know of several Rodeo's that still ran after the battery polarity was reversed. They had an alternator problem and shift lock solenoid problem that had to be fixed but the PCM still worked.
What happened to your PCM?
Shorting +12 Vdc to ground would cause a spark and could blow a fuse but not likely to cause a PCM failure. How did you determine you had a PCM failure?
The spark on a 00-02 Trooper is produced by the Ion Sensing Ignition Module, there could by an issue with it. Check the plugs to it and make sure they are plugged in. The module is located on top of the intake manifold.
Did you or your mechanic connect a NOID lamp and see if the injectors were being pulsed?
Did your mechanic state that the injectors were being pulsed?
Ok, so no spark no fuel but with new Crankshaft Position Sensor. Don't buy the Ion Sense Ignition module.
Correct, the PCM/ECU has a Red 80 pin and a Blue 80 pin electrical connector.
The 8093935090 PCM/ECM is for a 2000 Trooper but your 2001 3.5L engine is identical to a 2000 3.5L so it should work OK. The difference between the auto trans version and manual trans version of the PCM/ECM is the 4L30e circuitry. Maybe your problem does not involve the PCM/ECM or possibly you let the smoke out of the 8093935090 PCM/ECM as well.
If you want to troubleshoot the problem yourself start by removing the PCM main relay located in the engine compartment fuse and relay box. The PCM relay should be #13 in the attached diagram.

Measure the DC voltage between each pin in the relay socket and the negative battery terminal with the ignition switch in the Run position. Make sure the battery is fully charged before testing the voltage.
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Two of the ECM power relay socket pins should have battery voltage on them. One is continuous and one is switched On/Off by the Ignition Switch. 13.7 Vdc and 0.95 Vdc is unexpected, which of the two is switched?

Does the socket have five pins?
The PCM Power Relay has to have more than 2 pins (typically 5) so apparently your fuse and relay box does not match the diagram I posted. See if you can locate the PCM Power Relay in the fuse and relay box and rerun the test.
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Since you have determined which two pins are the relay coil, bench test the relay by checking the actual resistance between the other two pins when you apply 12 Vdc across the coil pins. The expected resistance is less than 1/2 ohm with 12 Vdc applied and infinity with power removed.
Remove a fuel injector electrical connector and measure the voltage between each harness connecctor pin and the battery negative terminal with the Ignition Switch in Run with the original relay installed and again with the replacement relay installed.
Only one injector connector pin will have battery voltage on it.
Does it look like this one?
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It has been a while since I removed a FJ connector but as I recall you first have to pull up the securing clip on the RH side of the connector.
Only need to measure the voltage on one.
Are you referring to the blue tab? View attachment 123039
As I recall, the blue widget is a locking device. Try moving it up.
The tests confirm there is enough voltage at the injector for it to operate. If you measured the same voltage at the Ignition coils they should operate as well. I need to go back and review all your posts to determine what to test next.

Can you post a picture of the burned part of the original PCM?
I am having a very hard time believing the damage to the PCM circuit board was caused by a momentary short circuit that blew the 20 amp Audio/Tel fuse.
Are you sure the damaged PCM is actually the one that was in your truck to begin with?
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