u1421

[2Rowdy]

U1421 Implausible Ignition Key Off Time Received



Can someone please explain that code interpretation to me.

 

[HHhuntitall]

Hmm, appears to be a fairly new developement, say in the last 6 months..... A listing is found for it in the TSBs, under section 18, vehicle performance. Here's the link on TDR. .

https://www.turbodieselregister.com/membersonly/tsb/09tsb.htm

 

[2Rowdy]

Thanks for the link but I found what it was. I was wondering if someone could explain it in laymans terms. Oh well maybe it's just something because I am fully deleted. It's gone now.

 

[TLane]

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.



My guess is that either a glitch in the power at key on, loose battery connections, weak batteries, and/or the test is set too "tight" is causing the problem. I wouldn't worry about it unless it keeps happening.

 

[2Rowdy]

Thanks TLane.