O/D off light flashing?

edge186

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It's happened a couple times now. Truck running just fine then I stop at a stoplight or something and when I go to take off it pukes for a minute and the O/D off light on the shifter starts blinking. Any idea what this means?
 

TyCorr

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It's happened a couple times now. Truck running just fine then I stop at a stoplight or something and when I go to take off it pukes for a minute and the O/D off light on the shifter starts blinking. Any idea what this means?

Ideas? Yeah, you need to go into the diagnistics menu on that cts and select "read dtc's". Tell us what codes are stored in there. That would be a good.starting.point.

Could be your trans, tq conv, or vss(sensor in your rear differential housing).
 

ToMang07

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O/D light blinking means there is a tranny code.

If there was a chick in the passenger seat that had big feet, man hands, or an unusually large adams apple, that could set it off.

Otherwise.... check for codes.
 

Racer X

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It's happened a couple times now. Truck running just fine then I stop at a stoplight or something and when I go to take off it pukes for a minute and the O/D off light on the shifter starts blinking. Any idea what this means?

If "when I go to take off it pukes for a minute" means the engine lugs or bogs down, it sounds like you might have a drifting converter clutch partially applying when it shouldn't. That can set several DTC's related to transmission problems. Wouldn't hurt to check your transmission fluid level and condition. Read the codes and see what DTC's were set. :thumbup:
.
 

edge186

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If "when I go to take off it pukes for a minute" means the engine lugs or bogs down, it sounds like you might have a drifting converter clutch partially applying when it shouldn't. That can set several DTC's related to transmission problems. Wouldn't hurt to check your transmission fluid level and condition. Read the codes and see what DTC's were set. :thumbup:
.

Fluid level is normal and condition is good. It looks like brand new fluid.

Here is a pic of a DTC that is new within the last few days. Not sure what it means
 

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ToMang07

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Fluid level is normal and condition is good. It looks like brand new fluid.

Here is a pic of a DTC that is new within the last few days. Not sure what it means

That't a common code...means the batteries were disconnected, PCM fuse was pulled, or there is a programmer present that wiped the KAM memory.
 

edge186

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P0720 I'm not sure what that code means either but that one popped up as well.. I think that's the one. Any ideas?
 

TyCorr

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That is an OSS Sensor... Output Shaft Sensor.
That could be causing the od light to.flash. If there is.a discrepancy in shaft speeds, aka slippage, that may be the culprit. Although I didnt think the 4r100 was that advanced :shrug:
 

ToMang07

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That could be causing the od light to.flash. If there is.a discrepancy in shaft speeds, aka slippage, that may be the culprit. Although I didnt think the 4r100 was that advanced :shrug:

I could very well be wrong. That's what I got when I looked up the code.

This would definitely be a Mark question.
 

Mark Kovalsky

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That could be causing the od light to.flash. If there is.a discrepancy in shaft speeds, aka slippage, that may be the culprit. Although I didnt think the 4r100 was that advanced :shrug:
Yes it was that advanced. The 4R100 can detect slip, set a code, and flash the OD light. But that's not the code that has set here.

This code means the PCM isn't seeing the signal from the OSS, or the signal is noisy.

First, remove the sensor. It's on the rear of the trans on the top. One bolt holds it in. If there is junk on the bottom of the sensor, clean it off. This could be enough to fix it. Check the wiring harness for damage or corrosion where it plugs into the sensor. If neither of these fix it, the sensor may be bad.
 

TyCorr

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Yes it was that advanced. The 4R100 can detect slip, set a code, and flash the OD light. But that's not the code that has set here.

This code means the PCM isn't seeing the signal from the OSS, or the signal is noisy.

First, remove the sensor. It's on the rear of the trans on the top. One bolt holds it in. If there is junk on the bottom of the sensor, clean it off. This could be enough to fix it. Check the wiring harness for damage or corrosion where it plugs into the sensor. If neither of these fix it, the sensor may be bad.

Awesome info!

I always learn something when you post Mark, for that, thank you!
 

Racer X

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4X4 4R100's and 4X2 4R100's with PTO option have 2 shaft sensors. In the case at the front is the turbine shaft sensor (TSS) with the OSS in the extension housing. The PTO models use a different TSS than 4X4 models do.

Both sensors were added to the 4R100's to supplement the axle sensor so DTC's would be more accurate. Some DTC's had their meanings revised once the new sensors were added.

Previously, the PCM had no sensor in the transmission itself to detect slip. When the axle sensor was out of range, the PCM assumed it was the transmission. It then would set a DTC for trannsmission slip. However, the problem could be in the axle itself or anything between axle and transmission, including drive-line components and transfer cases on 4X4's. Some 4x2 4r100's have the OSS on the side of the extension housing where the speedometer cable would enter the tail section.

As mentioned, the actual DTC can be set due to a wiring problem or a bad or dirty sensor. Wiring is part of electronic control systems as it depends on it to work correctly.

The system is advanced, but it can't tell the difference between mechanical failure and Electronic Control System failure. DTC's are a clue a tech uses to determine if a mechanical or electronic system failure exists. A bad PCM will set DTCs that are false. I mentioned bad PCM due to the Keep Alive Memory (KAM) DTC set.
Yes, disconnecting battery power will set this code, which makes it common. Edge186 if your batteries went dead or you disconnected them, chances are thats what set the KAM DTC. A bad PCM thats lost it's memory circuits will too. Usually there are other symptoms when the PCM has lost it's memory capability.

In the early days of electronic control systems they controlled the engine only. Precise control of air to fuel ratios in gasoline engines is where they really shine. They improved engine performance while actually exceeding emission and MPG standards imposed on the automakers by law. When it came to Power-train control, electronics were asked to take the place of the linkage, cable and vacuum signal that always worked reliably. Those are big shoes to fill. I remember when the magnetic fields from alternators and starters interfered with some early sensors which had to be revised. That was what coined the phrase "noisy signal." ;)

Racer
Product research and development consultant to the automotive industry.
Certified specialist on automotive electronic control systems, diesel and gasoline engines, custom transmission, powertrain and engine builder.
 

edge186

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4X4 4R100's and 4X2 4R100's with PTO option have 2 shaft sensors. In the case at the front is the turbine shaft sensor (TSS) with the OSS in the extension housing. The PTO models use a different TSS than 4X4 models do.

Both sensors were added to the 4R100's to supplement the axle sensor so DTC's would be more accurate. Some DTC's had their meanings revised once the new sensors were added.

Previously, the PCM had no sensor in the transmission itself to detect slip. When the axle sensor was out of range, the PCM assumed it was the transmission. It then would set a DTC for trannsmission slip. However, the problem could be in the axle itself or anything between axle and transmission, including drive-line components and transfer cases on 4X4's. Some 4x2 4r100's have the OSS on the side of the extension housing where the speedometer cable would enter the tail section.

As mentioned, the actual DTC can be set due to a wiring problem or a bad or dirty sensor. Wiring is part of electronic control systems as it depends on it to work correctly.

The system is advanced, but it can't tell the difference between mechanical failure and Electronic Control System failure. DTC's are a clue a tech uses to determine if a mechanical or electronic system failure exists. A bad PCM will set DTCs that are false. I mentioned bad PCM due to the Keep Alive Memory (KAM) DTC set.
Yes, disconnecting battery power will set this code, which makes it common. Edge186 if your batteries went dead or you disconnected them, chances are thats what set the KAM DTC. A bad PCM thats lost it's memory circuits will too. Usually there are other symptoms when the PCM has lost it's memory capability.

In the early days of electronic control systems they controlled the engine only. Precise control of air to fuel ratios in gasoline engines is where they really shine. They improved engine performance while actually exceeding emission and MPG standards imposed on the automakers by law. When it came to Power-train control, electronics were asked to take the place of the linkage, cable and vacuum signal that always worked reliably. Those are big shoes to fill. I remember when the magnetic fields from alternators and starters interfered with some early sensors which had to be revised. That was what coined the phrase "noisy signal." ;)

Racer
Product research and development consultant to the automotive industry.
Certified specialist on automotive electronic control systems, diesel and gasoline engines, custom transmission, powertrain and engine builder.
I had recently disconnected the PCM to pull the chip out of it. I also recently wrecked the truck so it was in the shop for a couple weeks and the batteries were disconnected during that time. Either of those had to have set that code. I will check the OSS sensor when I get a chance.
 

Coolit

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I know this is an older thread but

Hello everyone this my first post to the forum I'm new here and a complete newbie to the diesel engine family hopefully I don't get on anyone's nerves asking to many questions I had a heart attack 3 years ago so some times I don't pick up on things right away but I have a 2001 7.3 the chip is 6 or 7 years old I just bought this truck a month ago and I know this is an older thread but I'm having this very problem I have a ts 6 position performance chip new re-man engine new re-man transmission every time I put the chip in the OD off light flashes as soon as I take off i get back turn the truck off take the chip out restart the truck and go down the road everything is all good I'm at my wits end over this thing I really like the power and mpg and would like to keep it installed but I can't stand that light flashing I had to put another pcm in the truck also because some nit wit didn't have the harness engaged properly and tighten down I would very much appreciate it if someone could help me resolve this issue.
Thank you for your time and hopefully patiences
 
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Mark Kovalsky

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The ONLY way you're going to fix this is to find out what code was set. You can get Forscan software free at Forscan.org and buy an ELM327 adapter at Amazon.com for under $30. That will read the codes. Or you could take it to a good independent shop or a Ford dealer. The places that read codes free do not have readers that can read these codes.
 

Coolit

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Ok thanks I have the ELM327 adapter already and forscan I'm guessing I need to reinstall the chip run it then scan for codes and report back

Thanks again
 

Coolit

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The only code I have is P0720 when the chip is plugged in and no codes what so ever with the chip out
 

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