P20F5 Reductant Consumption Too HIgh
Thread Starter
Junior Member
Joined: Aug 2013
Posts: 54
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2004 CLK 55 Cabriolet
P20F5 Reductant Consumption Too HIgh
Hey all, I searched several ways for an answer to my question but didn't turn up an answer.
2015 ML250, CEL light on. I ran the code. It came up on the $7E8 module and the code is "P20F5": "Reductant Consumption Too High"
I tried erasing the code but it kept coming up. Vehicle seems to be running fine.
Anyone have an idea what this means?
Thanks!
2015 ML250, CEL light on. I ran the code. It came up on the $7E8 module and the code is "P20F5": "Reductant Consumption Too High"
I tried erasing the code but it kept coming up. Vehicle seems to be running fine.
Anyone have an idea what this means?
Thanks!
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Joined: Jan 2009
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From: V E G A S
1922 Ford Model T / no OBD
reductant aka DEF aka addBlue fluid.
How often you have to add it?
Don't recall reading about the code, but the only thing that comes to mind is wear out DEF injector.
How many miles?
How often you have to add it?
Don't recall reading about the code, but the only thing that comes to mind is wear out DEF injector.
How many miles?
Thread Starter
Junior Member
Joined: Aug 2013
Posts: 54
Likes: 8
2004 CLK 55 Cabriolet
I believe DEF fluid was added by the dealer at the 50k service. Vehicle now has just under 55,000.
Should I go get some DEF and fill? There are no warnings or messages in ASSYST telling me to fill the DEF tank.
Last edited by slimpee; Dec 3, 2020 at 02:19 PM.
MBWorld Fanatic!
Joined: Jan 2009
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From: V E G A S
1922 Ford Model T / no OBD
You might add DEF just to monitor the consumption, but inspect the injector visually, clean it and try to get a scanner who will show live data for the system. .
Last edited by kajtek1; Dec 3, 2020 at 02:20 PM.
Thread Starter
Junior Member
Joined: Aug 2013
Posts: 54
Likes: 8
2004 CLK 55 Cabriolet
My scanner allows for live data. What should I look for?
Thank you again!
MBWorld Fanatic!
Joined: Jan 2009
Posts: 9,224
Likes: 1,798
From: V E G A S
1922 Ford Model T / no OBD
See if you can display DEF injection.
I've never had to go that far, but there have to be norms for it. Autotel seems to have programmed limits, but that is above DIY level.
Eventually you can replace DEF injector, but beware that your MY is subject to SCN coding, so for module replacement you need a dealer programming.
I've never had to go that far, but there have to be norms for it. Autotel seems to have programmed limits, but that is above DIY level.
Eventually you can replace DEF injector, but beware that your MY is subject to SCN coding, so for module replacement you need a dealer programming.
