U0401 Error in my Ford Fiesta S 1.6 2012

[renz]

Last week, when I started my Ford Fiesta S 1.6 2012, it showed a check engine, traction control light, and hill start assist on my dashboard. The RPM of my car has been unstable.



I have a portable scanner and returned a P0351 Ignition Coil A Primary / Secondary Circuit error. I had the ignition coil replaced at a local mechanic. After replacing the ignition coil, the misfiring seems to be fixed:



But when the mechanic had it scanned again, it showed two more errors: U0401:00-2B and U0401:00-2F


Has anyone encountered the same problem? And what did you do to fix this?

 

[Handy Andy]

It's the P0351 - are the plug wires ok?

The process to even detect this code requires a misfire - but the way it can detect this is thru various methods and it uses the output of one sensor to help detect misfires - but the way the plug wires fire - affects the output in a different way when one cylinder misfires on a regular basis making the other sensor see rich fuel conditions

Sometimes it can only guess because it sees the same result every time it looks for results.

It's letting you know that the spikes in the primary for each plug - it sees a different result on one - all the time. Or, its sending a signal but it doesn't seem to be pushing the spark into the plug to fire it.

You replaced the module, but did you check the boots, plug and or the wire and check for continuity in the wire, into the booth and it's connector to the top of the plug?