How to clear fault codes?

[88milesPerHour]

Could anyone tell me, are fault codes latching in other words they sustain until cleared by a full ECU reset or are they cleared on every engine restart and will therefore only reappear whilst the fault still exists?

I'm working my way through a code 26b problem.

Thanks in advance.

Duncan

[Chillidoggy]

I think they stay in the ECU, and you can clear them using Freescan. The code will then flash up again if the fault is detected.

[Barrykearley]

Like he says - you have to clear them with a pc or a tool. 

The cel light though I believe can go out if the error disappears and a quantity of good starts have occurred ?? I'm sure I have read that one somewhere 

[Chillidoggy]

7 posts in 10 years! That has to be some kind of record!

[Escape]

Faults are also cleared by leaving the ECM without power for some time, but then you'll also lose the adaptive values and the ECM will take some time to relearn.

[fjmuurling]

Three ways to clear them.

1 - disconnect the ECM from the battery, but you will also lose the "learning" parameters.

2 - with freescan or espritmon.

3 - After 50 "clean" starts (i.e. no (new) errors while running) the codes are reset. (this is for a SE and a S4S AFAIK) 

[Vulcan Grey]

Do not disconnect the Fuse for the ECU or the battery while the key is in the ignition!

[88milesPerHour]

Thanks all.

I used Espritmon to determine that I have a 26b fault. I have now read the user manual and found the reset command ('t'). Thanks for the specific guidance fjmuurling, greatly appreciated