I have an O4 Renault engine Magnum that is showing a inj/inop message, reluctant to do the diagnostic at Renault cus they will take me money for the diagnostic then say could be this or could be that. There seems to be no physical symptoms that I can detect so hoping my be a sensor. Any one any experience of this?
we had it coming up on a 54 plate from about 4 years old, renault at avonmouth said it was the injector pump that will fail, it was never done and is still running ok now, just used to switch ign off for a minimum of ten min and all seems ok. most of the fault codes are false even on the 59 plate we got, the gearbox one was the favorit when it rained.
Most likely one of the pumps - most display no symptoms when injection inop is on the dash. It it goes you’ll know from the mis-fire.I can’t remember if you can access the dashboard diagnostics for a fault code - Mack engines and Renault diagnostics never a happy marriage 
Steve
hotel magnum:
, the gearbox one was the favorit when it rained.
what message do you get ?
on rainy days I get " manual mode impossible" on my Premium !!
according to the dashboard computer, and phone help from Renault Exeter, it appears to be a wiring loom fault between the ECU and the Gearbox . Original thoughts were a dodgy ECU or a dodgy stalk !
Thanks for the feed back. Think I will have a poke around the wiring in the hope of finding a cheap fix then find a good injector specialist.
why not just get it plugged in? if it comes back as a mechanical fault then its either an injector or pump, if its electrical can start probe’ing around the harness. to me that would save time & in long run money.