Land Rover Discovery Owners & Service Manuals

Land Rover Discovery: General Information Charging System / Diagnosis and Testing

Land Rover Discovery (2009–2016) Service Manual / Electrical / Battery and Charging System / General Information Charging System / Diagnosis and Testing


For a detailed description of the Charging System, refer to the relevant Description and Operation section in the workshop manual. REFER to: Generator (414-02A Generator and Regulator - TD4 2.2L Diesel, Description and Operation), Generator (414-02B Generator and Regulator - GTDi 2.0L Petrol/GTDi 2.0L Petrol - SULEV, Description and Operation).



Diagnosis by substitution from a donor vehicle is NOT acceptable.

Substitution of control modules does not guarantee confirmation of a fault, and may also cause additional faults in the vehicle being tested and/or the donor vehicle.


  • If a control module or a component is suspect and the vehicle remains under manufacturer warranty, refer to the Warranty Policy and Procedures manual, or determine if any prior approval programme is in operation, prior to the installation of a new module/component.
  • When performing voltage or resistance tests, always use a digital multimeter accurate to three decimal places, and with an up-todate calibration certificate. When testing resistance always take the resistance of the digital multimeter leads into account.
  • Check and rectify basic faults before beginning diagnostic routines involving pinpoint tests.
  1. Verify the customer concern
  2. Visually inspect for obvious signs of damage and system integrity

Visual Inspection

Visual Inspection

  1. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step
  2. If the cause is not visually evident, verify the symptom and refer to the Symptom Chart, alternatively check for Diagnostic Trouble Codes (DTCs) and refer to the DTC Index
  3. Check DDW for open campaigns. Refer to the corresponding bulletins and SSMs which may be valid for the specific customer complaint and carry out the recommendations as required





For a list of Diagnostic Trouble Codes (DTCs) that could be logged on this vehicle, please refer to Section 100-00. REFER to: Diagnostic Trouble Code Index - DTC: Central Junction Box (CJB) (100-00 General Information, Description and Operation).

General information quiescent drain


On vehicles fitted with a Battery Monitoring System (BMS), the diagnostic routine for quiescent drain testing in the approved Jaguar or Land Rover diagnostic system should be utilized.

If a customer complains of a vehicle battery that discharges continuously or when left for a prolonged period of time, it is recommended that a quiescent drain test is performed as described below.

The battery drain should be measured using the approved Jaguar or Land Rover diagnostic system or a Digital Volt Ohm Meter (DVOM). A procedure for quiescent drain measurement using the diagnostic system is available in the Diagnosis and Testing section of the Workshop Manual. The vehicle should be in the locked/armed state (for example vehicle alarm fully armed), all doors, hood and luggage compartment lid/tailgate are open and latched (so as to appear closed from an electrical point of view). The test should take place after the vehicle has entered shutdown mode. The time taken for this to occur after the ignition is switched off varies according to model (Refer to the Topix On line resource for details).

When the vehicle is armed, the effect of the security system Light Emitting Diode (LED) flashing is to cause a pulsation in the measured current drain. In this case, either the average current should be taken (using a DVOM with an averaging system) or the current reading taken, ignoring the brief high current peaks.


Approved Jaguar or Land Rover diagnostic system with current probe OR DVOM with current probe.


Using an Approved Jaguar or Land Rover Diagnostic System.

  1. Switch off all electrical loads and ensure that the ignition is off (power mode 0)
  2. Connect the current probe to the approved Jaguar or Land Rover diagnostic system
  3. Calibrate the probe
  4. Install a clamp around the battery lead/junction box lead
  5. Go to the Quiescent Current Testing section in this procedure

Using a Digital Volt Ohm Meter (DVOM)

Do not use an in-line DVOM to measure the quiescent drain on vehicles fitted with an electronic throttle (for example Range Rover 2002MY onwards). The current exceeds the maximum amount the fuse in the DVOM is capable of handling.

  1. Switch off all electrical loads and ensure that the ignition is off (power mode 0)
  2. Connect the current probe to the DVOM
  3. Calibrate the probe
  4. Install a clamp around the battery lead/junction box lead
  5. Go to the Quiescent Current Testing section in this procedure


  1. Switch ignition to 'on' or select ignition power mode 6 in keyless vehicles and switch to 'off' (power mode 0) (do not crank)
  2. Remove key from ignition switch (if equipped)
  3. Open and latch all doors, hood and luggage compartment lid or tailgate
  4. Lock the vehicle using the remote function on the remote handset or smart key. (Single lock only to avoid volumetric alarm arming)
  5. Remove any other potential electrical drains such as accessories plugged into accessory sockets
  6. Record the amperage readings after the shutdown period referenced in the Topix on line resource for details. Note: all cars from 10MY onwards should be less than 30mA after 30 minutes (for exceptions see Land Rover Quiescent Drain Values table).
  7. Record the final reading on the battery report form.

The preferred method of testing following an excessive current consumption figure is to use a current probe around individual junction box leads to the various suspected circuits to identify a potential cause. This is in preference to the old method of removing fuses for the following reasons:

  • The drain may be caused by a control module remaining active and preventing the quiescent drain from reducing to normal levels
  • The drain may be caused by a relay winding that is activated. Pulling the fuse can allow this to 'reset' and the drain will be lost and go undiagnosed.





  1. The total current drain will be higher if certain approved accessories are fitted (for example: tracker, trailer module, etc.)
  2. Applies to vehicles without Tire Pressure Monitoring System (TPMS). Vehicle shut-down period with TPMS is approximately 15 minutes.


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