My check engine light came on yesterday. I was expecting a code 21 for the O2 sensor since I was tightening a bolt on my sliders and bumped it a bit.
It won’t clear or it comes back on immediately upon starting the truck. I’ve had the battery disconnected and the EFI fuse pulled.
However, when I go to read it the CEL just blinks consistently which indicates the system is working and there are no codes. What gives?
The truck runs the same— maybe a bit rougher at idle but I might be imagining that. There is some white goo on the diagnostic ports. I’m hoping it’s just dielectric grease. This is the first time I’ve had to read a code since buying the truck in July 2017.
It won’t clear or it comes back on immediately upon starting the truck. I’ve had the battery disconnected and the EFI fuse pulled.
However, when I go to read it the CEL just blinks consistently which indicates the system is working and there are no codes. What gives?
The truck runs the same— maybe a bit rougher at idle but I might be imagining that. There is some white goo on the diagnostic ports. I’m hoping it’s just dielectric grease. This is the first time I’ve had to read a code since buying the truck in July 2017.
Reading 3FE engine codes at home
I couldn't find this on Mud. Thanks to Aaron (Mr 2FE), he put this together some time back. I have had several questions about reading the check engine light on a 3FE lately, so here it is. I'll be adding it to the FAQ. Get a Haynes, Chilton’s, or a Factory Service Manual (FSM) For the FSM...
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