Code 452 logical troubleshooting plan?
Cargo Master
Joined: Aug 2021
Posts: 2,258
Likes: 742
From: Maryland
Yes, probably overkill, but I had a right front caliper catch fire in 2015 on another vehicle I owned. It was a super hot day out and it had been dragging. I used an entire fire extinguisher on it and didn't loose the vehicle. Maintenance is a lot easier than repairs, and you can choose when to do it, and work at an easier pace.
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5th Wheeling
Joined: Sep 2024
Posts: 32
Likes: 2
From: Fairbanks
It probably won't make any difference in how often you clean and grease, but I just thought I would let you know that the slides were working okay. The pistons were sticking in the calipers. The truck has 71K miles on it, and there was about an 1/8" of pad left, perhaps all original since 1996 and still working.
Cargo Master
Joined: Aug 2021
Posts: 2,258
Likes: 742
From: Maryland
It probably won't make any difference in how often you clean and grease, but I just thought I would let you know that the slides were working okay. The pistons were sticking in the calipers. The truck has 71K miles on it, and there was about an 1/8" of pad left, perhaps all original since 1996 and still working.
A larger point is, you'll discover problems like that with periodic maintenance. (EDIT: and I'm sure you know that from being an aircraft mechanic.)
The brake hoses are another culprit for disc brakes dragging. They collapse inside and don't let the fluid return out of the piston.
Yes, I check brakes, fluid level in my manual transmission and lug nut torque more often than most people, probably.
It's because I've had failures with each of those systems in the past. I also check oil, coolant and hoses, brake fluid level, and battery hold down clamps visually, once a day, before I drive my truck, unless it's pouring rain, etc.
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5th Wheeling
Joined: Sep 2024
Posts: 32
Likes: 2
From: Fairbanks
Yes on replacing the calipers. Also replacing the rotors, re-packing the bearings, replacing the pads, and flushing the brake fluid.
I checked the rear brakes. On most trucks I would replace the shoes, but as little as this truck will get driven, the meat that's still on the shoes will last at least a decade.
I don't think I'll replace the hoses, but it's something to consider, I may.
I will test drive when I'm done and make sure the brakes are not dragging before I turn the truck over to the landlady.
I applaud you for taking such good care of your truck, I just thought you might like to know that the stainless sliders(?) seem to do a very good job of allowing the calipers and pads to move. I think you're cleaning and lubing way more than is necessary, but you do that as often as you like.
Thanks for the input.
I checked the rear brakes. On most trucks I would replace the shoes, but as little as this truck will get driven, the meat that's still on the shoes will last at least a decade.
I don't think I'll replace the hoses, but it's something to consider, I may.
I will test drive when I'm done and make sure the brakes are not dragging before I turn the truck over to the landlady.
I applaud you for taking such good care of your truck, I just thought you might like to know that the stainless sliders(?) seem to do a very good job of allowing the calipers and pads to move. I think you're cleaning and lubing way more than is necessary, but you do that as often as you like.
Thanks for the input.
Hotshot
Joined: Jul 2020
Posts: 10,534
Likes: 2,662
From: Near Salt Lake City
1996 F250, Ext cab, 4x4, 460, E4OD?, 71k miles.
Just in case it's relevant, for about the last 5 years the truck has been used to haul a 450 gallon water tank 2-3 miles up a decent hill, the past 2 years only used in the summer. Prior to 5 years ago it was only used to haul water in the winter (very seldom), and used to tow a 22' Bayliner 7 hours to saltwater in the spring, launch the boat once in a while during the summer, and tow the boat back in the fall. The truck has sat a good bit, I know there are some corrosion issues. Last October I pulled the battery and took it into the house to keep it warm so it wouldn't discharge and freeze. The truck sat without a battery in it until May.
The truck belongs to my landlady, she hauls the water. She said that last time she got water, the OD light flashed, and it hicupped sometimes. I believe that means it shifted hard. Her late husband taught her to engage the overdrive off system when hauling water, which she said she does and did this last time.
I am a retired aircraft mechanic and I've always done most of my own vehicle maintenance, so I have some mechanic skills and tools, but a lot of this stuff is new to me.
I managed to find a code reader (OBD1) and got the 452 code, no other codes. I was reluctant to test drive it. I saw somewhere that it should not be driven when shifting hard because the trans could be damaged. From my internet research, I get the impression it's not that critical. At this point I am thinking test driving is okay, hauling 3200 lbs of water up a hill is probably not advisable.
I would like to try to fix this myself. Based on what I have learned (a lot of it from this forum), I have a plan. I would like some input on whether or not my plan is good, or suggestions on what to do and not to do.
My plan:
Pull the VSS and check it and clean it, and check the tone ring.
Check resistance of VSS
Check / clean the plug on the trans
Check for a delay in shifting into reverse
Test drive to verify speedometer works (she said she's pretty sure it did), check if speed control works
Test drive with RABS controller disconnected
Test drive with speed control box disconnected
Perhaps check VSS output depending on what I find with other checks
Any problems with that plan?
Any thoughts on damaging the transmission by test driving or hauling water?
Just in case it's relevant, for about the last 5 years the truck has been used to haul a 450 gallon water tank 2-3 miles up a decent hill, the past 2 years only used in the summer. Prior to 5 years ago it was only used to haul water in the winter (very seldom), and used to tow a 22' Bayliner 7 hours to saltwater in the spring, launch the boat once in a while during the summer, and tow the boat back in the fall. The truck has sat a good bit, I know there are some corrosion issues. Last October I pulled the battery and took it into the house to keep it warm so it wouldn't discharge and freeze. The truck sat without a battery in it until May.
The truck belongs to my landlady, she hauls the water. She said that last time she got water, the OD light flashed, and it hicupped sometimes. I believe that means it shifted hard. Her late husband taught her to engage the overdrive off system when hauling water, which she said she does and did this last time.
I am a retired aircraft mechanic and I've always done most of my own vehicle maintenance, so I have some mechanic skills and tools, but a lot of this stuff is new to me.
I managed to find a code reader (OBD1) and got the 452 code, no other codes. I was reluctant to test drive it. I saw somewhere that it should not be driven when shifting hard because the trans could be damaged. From my internet research, I get the impression it's not that critical. At this point I am thinking test driving is okay, hauling 3200 lbs of water up a hill is probably not advisable.
I would like to try to fix this myself. Based on what I have learned (a lot of it from this forum), I have a plan. I would like some input on whether or not my plan is good, or suggestions on what to do and not to do.
My plan:
Pull the VSS and check it and clean it, and check the tone ring.
Check resistance of VSS
Check / clean the plug on the trans
Check for a delay in shifting into reverse
Test drive to verify speedometer works (she said she's pretty sure it did), check if speed control works
Test drive with RABS controller disconnected
Test drive with speed control box disconnected
Perhaps check VSS output depending on what I find with other checks
Any problems with that plan?
Any thoughts on damaging the transmission by test driving or hauling water?
* Do the pinpoint tests in the PCED for your code
That way you will NOT be guessing
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5th Wheeling
Joined: Sep 2024
Posts: 32
Likes: 2
From: Fairbanks
I don't have a PCED. Is it available on line?
Would doing pinpoint tests require an o-scope? As previously stated, I don't have one.
Would doing pinpoint tests do any good when the fault is not present? So far the fault has not recurred, so apparently the PCM is happy with the signal it's receiving.
With an 0-scope, I may or may not be able to find something like a marginal signal. If I had an o-scope, I would try that. Other than that, I can't imagine what pinpoint testing could tell me without a hard fault, but I would be happy to look at a PCED and see if I think further testing at this point would be a good idea.
I am not just guessing. I think given the situation and the tools I have available, I am doing what I can to troubleshoot and isolate based on what I have learned about how the system works.
Would doing pinpoint tests require an o-scope? As previously stated, I don't have one.
Would doing pinpoint tests do any good when the fault is not present? So far the fault has not recurred, so apparently the PCM is happy with the signal it's receiving.
With an 0-scope, I may or may not be able to find something like a marginal signal. If I had an o-scope, I would try that. Other than that, I can't imagine what pinpoint testing could tell me without a hard fault, but I would be happy to look at a PCED and see if I think further testing at this point would be a good idea.
I am not just guessing. I think given the situation and the tools I have available, I am doing what I can to troubleshoot and isolate based on what I have learned about how the system works.
Hotshot
Joined: Jul 2020
Posts: 10,534
Likes: 2,662
From: Near Salt Lake City
Yes, online at AllData (costs-a-plenty)
But
AllData is free at your library
Usually just a multimeter
Never an oscilloscope
Sometimes a NGS scan tool to command things on and off or read pids
The pinpoint tests for a VSS code are usually all done with a DVOM
But
AllData is free at your library
Usually just a multimeter
Never an oscilloscope
Sometimes a NGS scan tool to command things on and off or read pids
The pinpoint tests for a VSS code are usually all done with a DVOM
Thread Starter
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5th Wheeling
Joined: Sep 2024
Posts: 32
Likes: 2
From: Fairbanks
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Hotshot
Joined: Jul 2020
Posts: 10,534
Likes: 2,662
From: Near Salt Lake City
Great
You will find it under powertrain management / computer controls / diagnosing and troubleshooting
Poke around in there and print a bunch of pages free, is what I do on a regular basis
Had to look up a backup camera (trunk harness problem) for a Jaguar XF last week
Love Fords, but I still work on Mercedes the most these days (harder, a bit more lucrative)
Had to put brakes on a S450 yesterday with the electronic park brake that must be retracted
Live and learn is my motto, my dad was a Dr. of education
You will find it under powertrain management / computer controls / diagnosing and troubleshooting
Poke around in there and print a bunch of pages free, is what I do on a regular basis
Had to look up a backup camera (trunk harness problem) for a Jaguar XF last week
Love Fords, but I still work on Mercedes the most these days (harder, a bit more lucrative)
Had to put brakes on a S450 yesterday with the electronic park brake that must be retracted
Live and learn is my motto, my dad was a Dr. of education
Thread Starter
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5th Wheeling
Joined: Sep 2024
Posts: 32
Likes: 2
From: Fairbanks
Update:
Brake job is done, and all seems to be good with brakes. I did some test driving, and twice I got the hard shifting and the flashing OD light. I disconnected the RABS control box, and I have not gotten the hard shifting and OD light flashing since. I didn't drive it a lot after disconnecting the RABS control module, but enough that I think it might have made a difference. I will do some more test driving. I have not yet gone to the local library and looked at the PCED, that is on the "to do" list. I did not check codes again after the test drive, I will do that, but I'm guessing that it will be the same code.
I have another problem that I'm pretty sure is not related to brakes, but I'm wondering if it could be related to the 452 code. At low speeds, cornering on pavement, I feel a chatter, or shudder. I don't feel it on gravel. The only thing I can think of that would make this kind of chatter / shudder is the limited slip clutches. I know that the truck has some sort of a traction device in the rear end, I'm guessing it's a factory limited slip. Chatter seems to get worse as the turn radius gets tighter, and as speed is increased. I noticed this before I did the brake job, so it is not new. I hoped that it was related to brakes, but apparently it was not.
As mentioned in a previous post, there was a thin layer of fine dark material on the sides of the VSS, I thought it might be clutch material, now I am thinking that even more.
I don't know the maintenance history of the truck, but I do know who the truck belonged to for the last 23 + years, and I doubt it has had the gear oil in the rear end changed.I plan to check the driveline: u-joints, double cardan joints, or????
Any other suggestions on what else it could be?
Any suggestions on how to isolate the chatter to the rear end, or other?
Brake job is done, and all seems to be good with brakes. I did some test driving, and twice I got the hard shifting and the flashing OD light. I disconnected the RABS control box, and I have not gotten the hard shifting and OD light flashing since. I didn't drive it a lot after disconnecting the RABS control module, but enough that I think it might have made a difference. I will do some more test driving. I have not yet gone to the local library and looked at the PCED, that is on the "to do" list. I did not check codes again after the test drive, I will do that, but I'm guessing that it will be the same code.
I have another problem that I'm pretty sure is not related to brakes, but I'm wondering if it could be related to the 452 code. At low speeds, cornering on pavement, I feel a chatter, or shudder. I don't feel it on gravel. The only thing I can think of that would make this kind of chatter / shudder is the limited slip clutches. I know that the truck has some sort of a traction device in the rear end, I'm guessing it's a factory limited slip. Chatter seems to get worse as the turn radius gets tighter, and as speed is increased. I noticed this before I did the brake job, so it is not new. I hoped that it was related to brakes, but apparently it was not.
As mentioned in a previous post, there was a thin layer of fine dark material on the sides of the VSS, I thought it might be clutch material, now I am thinking that even more.
I don't know the maintenance history of the truck, but I do know who the truck belonged to for the last 23 + years, and I doubt it has had the gear oil in the rear end changed.I plan to check the driveline: u-joints, double cardan joints, or????
Any other suggestions on what else it could be?
Any suggestions on how to isolate the chatter to the rear end, or other?
Thread Starter
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5th Wheeling
Joined: Sep 2024
Posts: 32
Likes: 2
From: Fairbanks
So far, it appears you were right, although I may just not have seen the fault resurface yet. Intermittent failures can be such a pain.......
Why did you suspect the RABS computer? Is it a common failure? Is it usually something visibly damaged on a PC board? Is it something a person with some electronics experience might be able to fix, or just replace it?
I'm not convinced yet, just looking to verify, and thinking about options for a fix.
Thanks.
Thread Starter
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5th Wheeling
Joined: Sep 2024
Posts: 32
Likes: 2
From: Fairbanks
I put 4 oz of friction modifier in the diff, the chatter is gone.
No more hard shifting or OD light flashing since I disconnected the RABS computer. I still need to go to the library and look at the PCED. I'm not convinced that the RABS computer is at fault yet, but it's looking that way.
I'm starting to feel like I can relax some, the truck drives pretty well now with the brakes fixed and the chatter gone. I just need to finish up on the 452 fault.
I'm tired of wrenching, tomorrow I plan to take a break, maybe do some fishing.
Thank you all for the help!
No more hard shifting or OD light flashing since I disconnected the RABS computer. I still need to go to the library and look at the PCED. I'm not convinced that the RABS computer is at fault yet, but it's looking that way.
I'm starting to feel like I can relax some, the truck drives pretty well now with the brakes fixed and the chatter gone. I just need to finish up on the 452 fault.
I'm tired of wrenching, tomorrow I plan to take a break, maybe do some fishing.
Thank you all for the help!
Thread Starter
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5th Wheeling
Joined: Sep 2024
Posts: 32
Likes: 2
From: Fairbanks
It took a bit of driving, but the problem happened again with the RABS module disconnected. I disconnected the Speed Control module, but haven't driven the truck since.
I did go to the local library to try to find the PCED, no joy.
WIth no PCED, and no O-scope I'm limited on options. I believe I'll drive the truck some more to see if haveing the Speed Control module disconnected makes a difference. I will do some visual inspections on wiring and the PSOM. I will check wiring with an ohmmeter. I will re-seat connectors. I found a test on this forum for pinion movement, I will try that. I will look for another PSOM to try.
I did go to the local library to try to find the PCED, no joy.
WIth no PCED, and no O-scope I'm limited on options. I believe I'll drive the truck some more to see if haveing the Speed Control module disconnected makes a difference. I will do some visual inspections on wiring and the PSOM. I will check wiring with an ohmmeter. I will re-seat connectors. I found a test on this forum for pinion movement, I will try that. I will look for another PSOM to try.