HELP ECM Gone Bad!!
09-21-2008, 06:13 PM
#21
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Scikotics
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Hmm, for the pedal sensor, you would also want to do a sweep test to measure its resistance. Preferably with an analog meter, which makes it easier to see glitches in the sweep as you move the pedal. Not sure if that is the type of test you did from your description. But if so and all else tests good, and you have the PCM fault code, you may indeed have a bad ECU. If I recall correctly, you cannot remove either the rom or flash units from the board on our ECU's. If you can, you could attempt to pull them and plug them back in. On some older vehicles with removable EPROM's this would fix some issues, but like I said, I dont believe any of the memory is socketed in the newer ones. I havent had one of the ECU's apart in quite some time.
09-21-2008, 06:56 PM
#22
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Originally Posted by touringcoupe06
it cuts out at certain rpm whether i'm at wot or just cruising, but its never a specific rpm, and sometimes when I come to a stop it will hunt for idle, it will drop down below 200 rpm, then ramp up to 1500, but all the symptoms are so sporadic that I can never duplicate them. I've tried hooking up toyota's scan tool and shaking/wiggling all the wiring just in case its a loose connection but I never get it to do it, it also doesn't matter when it comes to engine temp, it's done when it's cold as well as when it's at full operating temperature and anywhere in between. I've run out of all other possibilities. The code for the mil light is P0606 which is described as a "PCM Processor Fault".
09-21-2008, 07:29 PM
#23
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Originally Posted by engifineer
Hmm, for the pedal sensor, you would also want to do a sweep test to measure its resistance. Preferably with an analog meter, which makes it easier to see glitches in the sweep as you move the pedal. Not sure if that is the type of test you did from your description. But if so and all else tests good, and you have the PCM fault code, you may indeed have a bad ECU. If I recall correctly, you cannot remove either the rom or flash units from the board on our ECU's. If you can, you could attempt to pull them and plug them back in. On some older vehicles with removable EPROM's this would fix some issues, but like I said, I dont believe any of the memory is socketed in the newer ones. I havent had one of the ECU's apart in quite some time.
09-21-2008, 07:30 PM
#24
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Originally Posted by toyota_scion_tc
Originally Posted by touringcoupe06
it cuts out at certain rpm whether i'm at wot or just cruising, but its never a specific rpm, and sometimes when I come to a stop it will hunt for idle, it will drop down below 200 rpm, then ramp up to 1500, but all the symptoms are so sporadic that I can never duplicate them. I've tried hooking up toyota's scan tool and shaking/wiggling all the wiring just in case its a loose connection but I never get it to do it, it also doesn't matter when it comes to engine temp, it's done when it's cold as well as when it's at full operating temperature and anywhere in between. I've run out of all other possibilities. The code for the mil light is P0606 which is described as a "PCM Processor Fault".
09-22-2008, 03:32 AM
#25
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Originally Posted by touringcoupe06
Originally Posted by toyota_scion_tc
Originally Posted by touringcoupe06
it cuts out at certain rpm whether i'm at wot or just cruising, but its never a specific rpm, and sometimes when I come to a stop it will hunt for idle, it will drop down below 200 rpm, then ramp up to 1500, but all the symptoms are so sporadic that I can never duplicate them. I've tried hooking up toyota's scan tool and shaking/wiggling all the wiring just in case its a loose connection but I never get it to do it, it also doesn't matter when it comes to engine temp, it's done when it's cold as well as when it's at full operating temperature and anywhere in between. I've run out of all other possibilities. The code for the mil light is P0606 which is described as a "PCM Processor Fault".
09-22-2008, 10:49 AM
#27
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Originally Posted by touringcoupe06
I've never done anythin with the secondary O2 but i looked at it with the scan tool and it was pretty much flat voltage like it's supposed to be and I've also already cleaned the MAF.
09-22-2008, 09:06 PM
#28
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the secondary O2 should not fluctuate very much at all thats how the catalyst effeciency monitor works. It tests to see if the cat is working by looking at the switching of the front O2 and then at the rear and if the second O2 is switching like the first then the cat is not doing it's job.
09-29-2008, 10:53 AM
#29
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The ECU has parameters built in for the O2 sensor and if the sensor isn't within these parameters it sets the CEL. I experimented a lot with antifoulers and looking at the voltage with my scan tool. The sensor still fluctuates with the cat working properly but it brings the voltage down rapidly once it goes up.
05-16-2023, 09:08 PM
#30
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Did you see if there were any DTC's in the ECM? If the scan tool communicates with the ECM I still find it hard to believe it's the ECM. Did you check every fuse, replay, and even look at the theft system to make sure something didn't mess up on it? I would hate to see someone spend money for an ECM and it turned out to be something else. Once the ECM has been programmed to the VIN it can't be changed.
how so? there are used ecm's for sale u telling me with techstream i cant change the vin?
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