Back to website first page
Back to Range Rover first page

RANGE ROVER/DISCOVERY WITH 3.5/3.9 LITRE ENGINE
(CAT & NON CAT) and HOT WIRE AIRMASS SYSTEM (from 1990)
- Possible ECU/airmass meter failure symptoms


The Lucas 14CU 'hot wire' airmass system ECU has proved to be more reliable than the earlier 'moving flap' airflow system 4CU ECU. Please click here for ECU photo. A common ECU problem we see is loss of 1 (or both) injector banks (usually following work in engine compartment) This failure is relatively easy to diagnose (check for injector pulses).

Early 3.9 ECU type number PRC7081 (superceded by PRC9061) develops a misfire at 2,800rpm (most noticeable at motorway speeds when overtaking). We now have a fix for this.

14CU ECUs as a group can suffer from intermittent running problems - such as running rich or cutting out for short periods - which are very difficult to diagnose so when there are vehicle problems we STRONGLY recommend road testing with a substitute before condemning your ECU.

Air mass meters are also causing running problems as vehicles age. Again, because diagnosis is so difficult, we STRONGLY recommend road testing road with a substitute before condemning air mass meter.

IN ALL CASES OF HOTWIRE system 3.5/3.9 vehicles (from 1990) WITH IDLING OR RUNNING PROBLEMS REFER TO THIS DIAGNOSTIC CHECKLIST BEFORE PROCEEDING.

We have a repair and rebuild service for these ECUs - Please click here for full address and repair quote form.

Back to Range Rover first page
Back to website first page