Upshift light coming on in an automatic

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Flcnj94

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I bought an 02 Sahara 4.0 automatic. When driving the upshift indicator (yellow up arrow) on the dash comes on when it’s shifting gears… when I get to I guess the last gear around 40mph the arrow comes on and off and on and off a few times over a few seconds and it feels like the jeep is trying to shift and stop and shift and stop and then finally shift - going along with the light.

1- is this normal for an automatic at all? I thought the light only illuminated in a manual jeep. I checked my build sheet and it’s always been an automatic jeep. Then I thought it was just a funky wiring thing illuminating the light in the dash but it seems like the transmission is actually functioning according to the light.

2- what can I do about this? Would it be a computer thing? (Note: there seems to have been a computer change from stock, an ARES technologies computer). Or wiring? Or? I’m lost but it seems like that light is negatively affecting the way the jeep shifts and when.

Thanks for any input
 
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I believe the indicator is connected strictly to the rpm’s and doesn’t have any say so on when the transmission shifts. That would suggest that your transmission in not shifting properly and the indicator notices it.
 
Flcnj94 said:
I bought an 02 Sahara 4.0 automatic. When driving the upshift indicator (yellow up arrow) on the dash comes on when it’s shifting gears… when I get to I guess the last gear around 40mph the arrow comes on and off and on and off a few times over a few seconds and it feels like the jeep is trying to shift and stop and shift and stop and then finally shift - going along with the light.

1- is this normal for an automatic at all? I thought the light only illuminated in a manual jeep. I checked my build sheet and it’s always been an automatic jeep. Then I thought it was just a funky wiring thing illuminating the light in the dash but it seems like the transmission is actually functioning according to the light.

2- what can I do about this? Would it be a computer thing? (Note: there seems to have been a computer change from stock, an ARES technologies computer). Or wiring? Or? I’m lost but it seems like that light is negatively affecting the way the jeep shifts and when.

Thanks for any input
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Take out the bulb?but like @Mindbinder3 mentioned could be an indication of something wrong
 
mrblaine said:
The upshift light coming on with an auto means that in all likelihood someone has swapped in the PCM for a manual. Post up the part number on it.
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This is what i think but would i have other symptoms as well having a manual computer in an auto?

@mrblaine part number 44298 Ares Technologies

ED50FB9E-D8F5-4813-98D8-C104ADF6A8E8.jpeg
 
Flcnj94 said:
This is what i think but would i have other symptoms as well having a manual computer in an auto?

@mrblaine part number 44298 Ares Technologies

View attachment 422698
Click to expand...

Part number does no good. Need the OEM number but the fact that it is an aftermarket programmed PCM tells you what the problem is. The only other symptom that may show up is the torque converter not locking up.
 
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mrblaine said:
Part number does no good. Need the OEM number but the fact that it is an aftermarket programmed PCM tells you what the problem is. The only other symptom that may show up is the torque converter not locking up.
Click to expand...

@mrblaine sorry for the delay, I got in contact with the owner or director of ARES technologies who told me that when the previous owner ordered a PCM through them, the VIN number provided was for a manual Jeep and not an automatic. So the PCM I have is for a manual. He offered me the opportunity to directly send my PCM for them to reprogram it to the specifications of my correct VIN number as an automatic. Says turnaround time is about 24 hours once received. Seems a little weird to me?

Regardless, do you think my symptoms are definitely due to that? While watching the dashboard more closely it looks like the jeep does not want to go past 2-2200 RPMs without shifting, once in third gear it will do higher RPMs no problem. So if i drive it pretty hard and quickly it Shifts through first fine, and as it makes it’s way to to 35-40, it’ll shift to 2nd and then the RPMS want to keep going up so the upshift arrow comes on and the jeep feels like it tries to shift again and again and again (upshift light coming on/off/on/off) almost like it’s slipping until it finally locks into 3rd gear and once up over 50mph it’s smooth sailing. It’s odd. Would this be related to the manual PCM? I know you mentioned torque converter so unsure if that may be related. The check engine for an o2 sensor weve replaced with a new NTK as suggested by the main post on this forum continually comes on as well after a few starts. @Wranglerfix I’ve seen others suggest you as the jeep PCM expert - does this all sound like PCM related issues to you? Come to think of it I may be better off just ordering a new PCM through you all together. I’m just concerned this is more than PCM and may be a tranny issue also? Please let me know any thoughts. Thank you so much!
 
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That the PCM was mistakenly programmed for a manual transmission would not be the cause of your engine not wanting to rev past 2200 rpms.
 
Jerry Bransford said:
That the PCM was mistakenly programmed for a manual transmission would not be the cause of your engine not wanting to rev past 2200 rpms.
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It will do higher RPMs but it’s like it wants to only in 3rd gear. Once in 3rd I can really coast at any speed up to 85-90 at 3-3500 RPMs no problem. It just seems very weird to me and it seems on @Wranglerfix ’s website testimonials some others with faulty PCMs experience bad or long or harsh shifting also so I’m hoping it is related to an incorrect and also faulty PCM.
 
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Your transmission is purely hydraulic and its shifting is not controlled by the PCM. The only thing the PCM controls on the transmission is the lockup for its torque converter.
 
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Flcnj94 said:
@mrblaine sorry for the delay, I got in contact with the owner or director of ARES technologies who told me that when the previous owner ordered a PCM through them, the VIN number provided was for a manual Jeep and not an automatic. So the PCM I have is for a manual. He offered me the opportunity to directly send my PCM for them to reprogram it to the specifications of my correct VIN number as an automatic. Says turnaround time is about 24 hours once received. Seems a little weird to me?

Regardless, do you think my symptoms are definitely due to that? While watching the dashboard more closely it looks like the jeep does not want to go past 2-2200 RPMs without shifting, once in third gear it will do higher RPMs no problem. So if i drive it pretty hard and quickly it Shifts through first fine, and as it makes it’s way to to 35-40, it’ll shift to 2nd and then the RPMS want to keep going up so the upshift arrow comes on and the jeep feels like it tries to shift again and again and again (upshift light coming on/off/on/off) almost like it’s slipping until it finally locks into 3rd gear and once up over 50mph it’s smooth sailing. It’s odd. Would this be related to the manual PCM? I know you mentioned torque converter so unsure if that may be related. The check engine for an o2 sensor weve replaced with a new NTK as suggested by the main post on this forum continually comes on as well after a few starts. @Wranglerfix I’ve seen others suggest you as the jeep PCM expert - does this all sound like PCM related issues to you? Come to think of it I may be better off just ordering a new PCM through you all together. I’m just concerned this is more than PCM and may be a tranny issue also? Please let me know any thoughts. Thank you so much!
Click to expand...

You couldn't pay me enough to put a piece of tape over a light that isn't supposed to be there so I would get the correct PCM programming installed and solve that problem. That knocks one off the list and then you can start on the rest.
 
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