Code U 1421
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Code U 1421
”Implausible ignition key off time“
does anyone have an idea of what this means.
2007 119000 miles original owner no mods
any help appreciated
truck runs like the day I bought it
does anyone have an idea of what this means.
2007 119000 miles original owner no mods
any help appreciated
truck runs like the day I bought it
Advocate of getting the ban button used on him...
Joined: Aug 2005
Posts: 5,082
Likes: 9
From: Live Oak Texas
This is just something I found on the internet. Doesn't seem to be a big deal unless it keeps happening.
The ECM keeps a timer of how long the truck has been turned off. It uses the timer to determine when it's OK to run certain tests. For example, if the truck has been off for at least 8 hours, then the temperature sensors (engine coolant, ambiant air, incoming air) should all read the same, more or less. In order to make sure that this timer actually works, the ECM checks to see that it incremented by at least some small amount when the key is turned on. If the timer doesn't increment, then you get "implausible", i. e. there's no way you could turn the key off and back on that fast.
The ECM keeps a timer of how long the truck has been turned off. It uses the timer to determine when it's OK to run certain tests. For example, if the truck has been off for at least 8 hours, then the temperature sensors (engine coolant, ambiant air, incoming air) should all read the same, more or less. In order to make sure that this timer actually works, the ECM checks to see that it incremented by at least some small amount when the key is turned on. If the timer doesn't increment, then you get "implausible", i. e. there's no way you could turn the key off and back on that fast.
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