PM11_Active values
Thread Starter
|
Trailering
Joined: Oct 2024
Posts: 20
Likes: 4
PM11_Active values
- Do these values mean the particulate matter sensor is broken?
- Can I get back to driving my truck - wait and see if the code comes up again?
- Should I trigger a manual regen before replacing the PM sensor? Might that somehow help?
- If the particulate matter sensor is broken, then the truck will not kick off regens on its own, right?
- The code's explanation says the PM sensor might be dirty. Can it be cleaned short of removing it from the tailpipe?
- Theoretically if I were to leave the possibly broken PM sensor in, while occasionally launching manual regens, then would I be able to safely operate the truck over long distances? Pure curiosity - if this had happened 700 miles away, could I have used manual regens to get home?
PM11_ACTIVE = No
PM_CURRENT = 0 mA
PM11 = 0 %
PM_CURRENT = 0 mA
PM11 = 0 %
I've been driving very short trips. Eventually was able to take a longer one. ScanGaugeIII showed a regen occurring. Watched as the soot % dropped, dropped, dropped, then stopped dropping. Regen remained active. I had to stop the truck. Regen hasn't started since then.
Last Week
Check Engine light on. Code showed P24AF. Manually cleared the DTC codes. Came right back. Parked it after I finished my trip. Ordered a new PM sensor.
This Week
Since then, all the emissions tests have reset. The p24AF is gone. New sensor has arrived. I've not been able to gently coax out the old PM sensor. I'll try removal again once the special line socket arrives.
Photo of metrics shown by ForScan
2016 F250 6.7
Mountain Pass
Joined: Dec 2024
Posts: 148
Likes: 86
I'm a newbie and can't answer your questions, but wanted to reply since I recently dealt with replacing my pm sensor. Be aware that the sensor likely is heat welded in place by the extreme temps from all the regens. I couldn't get mine out, so I took it to a guy who's done exhaust work in the rust belt for 30 years. He destroyed the bung threads trying to get it out. He eventually swapped in a used tailpipe from a deleted truck, but he destroyed two other tailpipes before he finally found one that he could get the old sensor out of. Just wanted to give a heads up about what you're in for.
Thread Starter
|
Trailering
Joined: Oct 2024
Posts: 20
Likes: 4
I'm a newbie and can't answer your questions, but wanted to reply since I recently dealt with replacing my pm sensor. Be aware that the sensor likely is heat welded in place by the extreme temps from all the regens. I couldn't get mine out, so I took it to a guy who's done exhaust work in the rust belt for 30 years. He destroyed the bung threads trying to get it out. He eventually swapped in a used tailpipe from a deleted truck, but he destroyed two other tailpipes before he finally found one that he could get the old sensor out of. Just wanted to give a heads up about what you're in for.
I've read on here that when the sensor gets stuck like that is to either (1) leave the sensor in + add in a new bung or (2) use this tool, ShockIt, by Promaxx.
New bungs: https://www.jteproducts.com/
ShockIt tool : https://promaxxtool.com/products/sho...-diesel-lt996d
Tuned
Joined: Nov 2016
Posts: 385
Likes: 116
From: Full time RVer
I'm a newbie and can't answer your questions, but wanted to reply since I recently dealt with replacing my pm sensor. Be aware that the sensor likely is heat welded in place by the extreme temps from all the regens. I couldn't get mine out, so I took it to a guy who's done exhaust work in the rust belt for 30 years. He destroyed the bung threads trying to get it out. He eventually swapped in a used tailpipe from a deleted truck, but he destroyed two other tailpipes before he finally found one that he could get the old sensor out of. Just wanted to give a heads up about what you're in for.
Thread Starter
|
Trailering
Joined: Oct 2024
Posts: 20
Likes: 4
Answering my own question using comments found on this forum.
Soot % Open vs Closed
Summary
Open Loop Soot% is a calculation based on many factors. It's used when soot % are high.
Closed Loop Soot% is based upon sensors in the exhaust - such as the Particulate Matter Sensor. On my truck, the Closed Loop % is labeled PM11%. It's used when soot % are low. I take it from @Work Truck Fanatic 's explanation that the Particle Matter Sensor isn't always turned on. This explains why there is a metric of PM_Active - yes/no and PM11=0% when I damn well knew the actual soot% was much higher.
So, no, a PM_ACTIVE = no does not mean the Particulate Matter Sensor is broken
Soot % Open vs Closed
Summary
Open Loop Soot% is a calculation based on many factors. It's used when soot % are high.
Closed Loop Soot% is based upon sensors in the exhaust - such as the Particulate Matter Sensor. On my truck, the Closed Loop % is labeled PM11%. It's used when soot % are low. I take it from @Work Truck Fanatic 's explanation that the Particle Matter Sensor isn't always turned on. This explains why there is a metric of PM_Active - yes/no and PM11=0% when I damn well knew the actual soot% was much higher.
So, no, a PM_ACTIVE = no does not mean the Particulate Matter Sensor is broken
Last edited by VAEWSaB; Oct 16, 2025 at 08:43 PM.
Fleet Mechanic
Joined: Oct 2022
Posts: 1,823
Likes: 898
From: Dallas Metroplex
Interesting coincidence, yesterday I received a letter in the mail from FoMoCo, that stated that if I had replaced a PM sensor in the past (and that it denied coverage under warranty) then they would now cover it. All that was needed was documented proof of labor and parts, and they would issue a refund check.
To the best of my knowledge that sensor has never been replaced (but, might've been by the first owner, however within 24k miles I highly doubt it). I know that I've never replaced it, so discarded the letter. But, the existence of the letter indicates that there must have been many denied warranty claims filed regarding the PM sensor, apparently. Enough so that FoMoCo now admits that it's problematic enough to allow coverage under warranty, and is refunding past replacement formerly denied.
So, I wouldn't discount the possibility that your PM sensor is acting up, perhaps...
To the best of my knowledge that sensor has never been replaced (but, might've been by the first owner, however within 24k miles I highly doubt it). I know that I've never replaced it, so discarded the letter. But, the existence of the letter indicates that there must have been many denied warranty claims filed regarding the PM sensor, apparently. Enough so that FoMoCo now admits that it's problematic enough to allow coverage under warranty, and is refunding past replacement formerly denied.
So, I wouldn't discount the possibility that your PM sensor is acting up, perhaps...
Thread
Thread Starter
Forum
Replies
Last Post
jellybean66
1987 - 1996 F150 & Larger F-Series Trucks
5
Mar 1, 2009 01:23 PM
