Relay van going in and out of limp mode

[Rorymac]

My van keeps going in and out of limp mode, I thought it might have been from not getting all the air out when I topped up the coolant. But that seems to be all ok now, no bubbles and the levels not dropping.

Problem is, whoever had it before might have remapped it so it won't show any fault codes when scanned. This is what the garage beside me (good guys that never charge me) but he's always flat out with amazon dsp vans so cant fit me in.

The eml will sometimes come on from a cold start, other times it will drive for 20 mins and then I lose torque. Sometimes it will drive for hours all fine and then it will go back into limp mode. From what ive read (not good with cars, I worked on boats and they were a lot less fiddly) it could be the nox sensor or an egr issue.

Anyone with any knowledge on these issues I would greatly appreciate your input.

TIA

[mickthemaverick]

Any faults involving limp mode often come down to battery condition. Check your battery voltage with everything turned off, it should be at least 12.7V, and then with the engine running it should show over 14V with headlights and heater fan turned full on. If it doesn't match those numbers give the battery an overnight charge and then retest. If you still have problems then a diagnostic scan is the way to go.

[Rorymac]

Its got a brand new battery, its only been in the van 3 months and voltage is spot on. It had a scan 2 days ago in the garage and it shows no fault codes .