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Discussion Starter · #61 ·
Also I checked all fuses . All of them are good .A/c fans kick on . No compressor . I think it’s the pcm again . . maybe just a bad one. it went strong for months.
 

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1966 Crown Coupe, 2016 200 S AWD, 1962 Lark Daytona V8.
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Check the A/C pressure transducer. If the PCM can't tell the discharge pressure it may default the cooling fans to 'on' and disable the compressor clutch.
It is on the 5 volt sensor line and may be what is pulling the line down?
See the 5 volt tree and disconnect each sensor until the voltage jumps to 5, then you have found the culprit.
The cam (dist) and crank sensors run on 8 volts. See attached:
 

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Discussion Starter · #65 ·
I can’t see the pdf . Thanks for replying , I disconnected the four sensors that run on 5volts . And with the key on . It still says 4.85 . Could this mean bad pcm again?​
 

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Unplug the connector from the PCM. Unplug all 4 sensors. That 5v wire should now read Infinite ohms to ground as it is disconnected from everything.
If it is open to ground and you are still seeing 4.85 volts, it sure sounds like a failing PCM. That is too low.
The regulated 5v sensor supply line should read 5v, give or take about a tenth of a volt.
 
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Discussion Starter · #68 ·
got 4.83v with all sensors unplugged .with the connector plug in to the top of the pcm . I went directly to the 5v wire on the pcm got the same voltage. what I don’t understand is with the connector unplugged . I go to the pin and nothing . Is there some sort of back feed voltage or resistor ?
Anyway I think it’s a bad pcm . I replaced the map sensor because I thought it maybe could be the root cause of that since it also works with intake pressure sensor .
two questions one is looking for a used pcm . I got this. Reman from rockauto they do not have anymore in stock . does it have to match exactly or could I just use one that’s from 96-2000? I noticed they have different letters on the end ? Is there a reason for this? This last one I just plugged in and drove fine .
question two . would a low voltage drop cause a pcm to burn out at some point ? maybe it’s my amps and compressors . I have air suspension. Maybe the draw could be the cause ?
 

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You would be able to do continuity (ohms) checks with that connector unplugged, not voltage checks. As long as that wire reads 'open' to ground with all possible loads disconnected, it should read OL or infinite ohms to ground.

I see that PCM went from 4606386AF to a 4606386AJ. I think that any 1997 JA or JX 2.5L would work. Older versions like *AA to *AI would work. Try to stick with the same model year as pinouts or other minor changes may have occurred.

Use these Mopar part #'s in your search:

81967
 

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Discussion Starter · #72 ·
I get ground when there all sensors are plugged in . As I take them off one by one I notice the one that stops the continuity is the map .
 

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MAP 5v supply shorted to ground?
Is it pretty much 0 Ω to ground?
Does the 5 volt line come up when everything except MAP is plugged in? Or is it still about 4.83v?
 

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Discussion Starter · #74 ·
MAP 5v supply shorted to ground?
Is it pretty much 0 Ω to ground?
Does the 5 volt line come up when everything except MAP is plugged in? Or is it still about 4.83v?
Same results the 5volts line never says nothing more then 4.84 . Am looking for another pcm . But what I have found that’s close is this 98 pcm different number on it . am out of ideas. My plan is to try This pcm and see if it removes the check light associated with the 5volts issue. That way I can get get my refund for the one i have . then get another one from all computers . that way am not left without one to move the car .
 

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Discussion Starter · #75 ·
Same results the 5volts line never says nothing more then 4.84 . Am looking for another pcm . But what I have found that’s close is this 98 pcm different number on it . am out of ideas. My plan is to try This pcm and see if it removes the check light associated with the 5volts issue. That way I can get get my refund for the one i have . then get another one from all computers . that way am not left without one to move the car .
82188
This is the one am looking. Seller says it’s a 98 2.5
Out of a sebring what you think ?
 

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The Vt/Wt wire out of C1-#61 is the 5 volts out to the sensors.
The Or/Wt wire out of C1-#44 is the 8 volts out to the Crankshaft Position and Camshaft Position (Distributor) sensors.
If either line is pulled down, it can cause a no start.

The internal regulated 5 and 8 volt supplies can also go into 'protection'. Once the issue is remedied, a key cycle (off/on) should bring the supply back on line.

I would start at the PCM. If the voltage is wrong, unplug the sensors and try again. Plug them back in one-by-one and when the voltage screws up again, the last one you plugged in should be the culprit.
 

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Discussion Starter · #77 ·
So I ran a few more tests with the 5v wire getting the same 4.84 volts . This is coming from the pcm .i pulled off all the sensors and the voltage doesn’t climb. Staying between 4.82-4.84 . Tryed it with the car on and off same result.
What I noticed is when I turned on my compressors the voltage went from 4.84 to 4.90 . only thought would be that the pcm was trying to compensate what it was losing . still no a/c as well . I really think that the pcm is done . Car starts and everything just no a/c and the check engine light will not rest .I also left the battery unplugged for 24 hrs same result .
 

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Discussion Starter · #78 ·
I assuming having the pcm flashed would not be a option? Since the pcm is giving a wrong voltage? or is that something that could be done?
 

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As long as your meter is correct, I would have to think the PCM internal hardware is failed. The regulated 5 volt output should be 5 volts, give or take a couple of hundredths of a volt (4.98-5.02).
The 5 volt line has a 'protection' mode where it will shutdown the line if it detects over-current, like a short. Maybe it took a hit from the MAP?
Replace the shorted MAP and the damaged PCM.

A flash can't change the intended application or core identity of the PCM. A 1997 JA/JX 2.5L Federal 50 state emission PCM can't be flashed or made into a different year, engine or emissions market. The PCM will always be what has been burned into the chip.
A flash only updates the existing software to fix or enhance program strategies for known problems. Chrysler still has to certify that any authorized PCM changes meet all government requirements. The part number will update when read with a DRBIII. After flashing, an Authorized Software Update label has to be applied both under the hood and on the PCM housing.

I would use this PCM as a 'trade-in' core for another PCM.
 
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Discussion Starter · #80 ·
As long as your meter is correct, I would have to think the PCM internal hardware is failed. The regulated 5 volt output should be 5 volts, give or take a couple of hundredths of a volt (4.98-5.02).
The 5 volt line has a 'protection' mode where it will shutdown the line if it detects over-current, like a short. Maybe it took a hit from the MAP?
Replace the shorted MAP and the damaged PCM.

A flash can't change the intended application or core identity of the PCM. A 1997 JA/JX 2.5L Federal 50 state emission PCM can't be flashed or made into a different year, engine or emissions market. The PCM will always be what has been burned into the chip.
A flash only updates the existing software to fix or enhance program strategies for known problems. Chrysler still has to certify that any authorized PCM changes meet all government requirements. The part number will update when read with a DRBIII. After flashing, an Authorized Software Update label has to be applied both under the hood and on the PCM housing.

I would use this PCM as a 'trade-in' core for another PCM.
Update I got the used pcm in .
it worked ! A/c back on. No check light . But I have a cruise control light that won’t turn off . That’s weird. Other then that . Looks to be all good . I’ll update more as I drive it .
 
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