PCM replace

Tiny
BRAEDEN FOWLER
  • MEMBER
  • 2002 DODGE DAKOTA
  • 4.7L
  • V8
  • 4WD
  • AUTOMATIC
  • 215,000 MILES
I recently scanned mytruck and I had a code come up I cannot remember what the code was. I found to test the yellow wire with dark green on pin 10 on the TCM to see if the PCM is putting out to much voltage. I should put out twelve volts but it is putting out over fourteen volts, but my truck runs fine no problems. There is a chip tune on it but we cannot find the chip to remove it if that could be it or not.
Friday, February 3rd, 2017 AT 3:53 PM

5 Replies

Tiny
CARADIODOC
  • MECHANIC
  • 33,867 POSTS
What problem are you trying to solve?

If you are working with some test procedure that asks you to make a "yes" or "no" decision based on a voltage reading, there is no difference between twelve volts and fourteen volts. The question is basically asking if you have something or nothing. The only way you can have fourteen volts anywhere is if the engine is running and the charging system is operating, otherwise you will have around 12.6 volts max.
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Friday, February 3rd, 2017 AT 4:01 PM
Tiny
BRAEDEN FOWLER
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It was putting out fourteen volts not running, but I am wondering if there is tunes from a chip on the vehicle, but we cannot find it to remove them. So is it the tunes that could make this code show up because the only this wrong so far is not so great fuel economy.
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Friday, February 3rd, 2017 AT 4:08 PM
Tiny
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Are you using an auto-ranging digital meter? If so, be sure it is not showing "millivolts". I have over a dozen meters I used in TV repair and auto electronics, but I never bought an auto-ranging meter because I get fooled too often.

The only tuning chips I am familiar with are add-on boxes that are hard-wired to the vehicle. A friend who specializes in rebuilding smashed Dodge trucks uses them but they are only effective at overcoming the limitations designed in by the engineers to increase reliability at the expense of power and fuel mileage on diesel engines. They do not do much for gas engines that you cannot do yourself by pushing the accelerator pedal further.

I get the feeling you are looking for a computer chip, (integrated circuit), that you can unplug like we did on 1980's GM Engine Computers. That is not the case with all other brands. The computers are sealed, but they do have software installed specific to the application. There is aftermarket software available that is installed via a laptop computer. Once that is done, if you don't have that software, the only way to remove it is to have the computer re-flashed at the dealership.

You have to read the fault codes again to know if it is even something that needs to be dealt with. If the Check Engine light was not on, the code does not refer to something that could adversely affect emissions. Some aftermarket code readers will display codes that cannot be avoided. An example would be a code for an open relay circuit for the AC compressor. That code will set on every vehicle that didn't come from the factory with air conditioning, but the Chrysler scanners and the vehicle will not display it. Aftermarket scanners and code readers might display it, but we know it can be ignored.

Do you know how to read the fault codes yourself?
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Friday, February 3rd, 2017 AT 4:31 PM
Tiny
BRAEDEN FOWLER
  • MEMBER
  • 3 POSTS
I used a Snap-On code reader at a local mechanics shop and they said to look into it but I forgot the code which is not helping and there is no engine light on for it. I am just lost cause the my vehicle system does not find this code, but the scanner does and and from what we found and tested was the test on the wire and the problem is there. But I do not have any problems with the truck at all.
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Friday, February 3rd, 2017 AT 5:05 PM
Tiny
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Chrysler made reading fault codes yourself much easier than any other manufacturer. Cycle the ignition switch from "off" to "run" three times within five seconds without cranking the engine, leave it in "run", then watch the codes show up in the odometer display. If it says "no codes", any codes picked up with aftermarket scanners either do not apply to your truck, or they are codes in different computers. Cycling the ignition switch only displays codes from the Engine Computer.
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Friday, February 3rd, 2017 AT 5:25 PM

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