Contents Wiring diagrams Section: Testing & Diagnostics All sections

Engine Controls - Trouble Shooting: Diagnosis Land Rover Discovery II

SYMPTOM DIAGNOSIS

Symptom checks cannot be used properly unless the problem occurs while the vehicle is being tested. To reduce diagnostic time, ensure steps in BASIC DIAGNOSTIC PROCEDURES and appropriate SELF-DIAGNOSTICS article were performed before diagnosing a symptom. Symptom checks are listed in order of probability, ease of accomplishment, and accessibility. Symptoms available for diagnosis are as follows

  1. Engine Hard To Start (Turns Over)
  2. Engine Does Not Start (Does Not Turn Over)
  3. Engine Hesitates Or Misses
  4. Engine Knock
  5. Loss Of Power
  6. Poor Fuel Mileage
  7. Rough Or Unstable Idle

INTERMITTENT PROBLEM DIAGNOSIS

Intermittent fault testing requires duplicating circuit or component failure to identify the problem. These procedures may lead to the computer setting a fault code (on some systems) which may help in diagnosis.

If problem vehicle does not produce fault codes, monitor voltage or resistance values using a Land Rover TestBook, an OBD-II scan tool or a DVOM while attempting to reproduce conditions causing intermittent fault. A status change indicates a fault has been located.

Use a Land Rover TestBook, an OBD-II scan tool or a DVOM to pinpoint faults. When monitoring voltage, ensure ignition switch is in ON position or engine is running. Ensure ignition switch is in OFF position or negative battery cable is disconnected when monitoring circuit resistance. Status changes during test procedures indicate area of fault.