Land Rover Defender: Low Battery Diagnostics

DIAGNOSIS AND TESTING

PRINCIPLES OF OPERATION

For a detailed description of the Charging System, refer to the relevant Description and Operation section in the workshop manual.

INSPECTION AND VERIFICATION

CAUTION: 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.

NOTES:

• If a control module or a component is at fault or may be at fault and the vehicle remains under manufacturer warranty, refer to the Warranty Policy and Procedures manual, or determine if any prior approval program 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-to-date 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

3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step
4. 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
5. Check the Jaguar Land Rover claims submission system for open campaigns. Refer to the corresponding bulletins and SSMs which may be valid for the specific customer complaint and complete the recommendations as required

SYMPTOM CHART

CUSTOMER QUESTIONNAIRE TO BE COMPLETED WHEN THE CUSTOMER PRESENTS A VEHICLE WITH THE COMPLAINT OF A LOW BATTERY

The following questions should be put to the customer on arrival at the service centre. The data gathered should be recorded and retained as the information may be needed to be added to a TA request for engineering evaluation if the vehicle's battery system fault. Select and record the appropriate response to each of the questions listed below:

• 1) Before the low battery was noted, had the vehicle doors been opened and closed multiple times while the vehicle had been unlocked and the engine off for over an hour or more (this may happen during loading and unloading of luggage, equipment, etc)? YES / NO
• 2) Has the Stop/Start function consistently been inhibited during the drive cycle? YES / NO
• 3) How often is the vehicle used? Daily / Every Other Day / Weekly / Less Than One Use A Week
• 4) What is the average length of journeys made? Less Than 10 Miles / Between 10 and 50 Miles / Over 50 Miles
• 5) How many engine starts (not including Stop/Start activations) does the vehicle typically undergo in one day? Less Than 5 / Greater Than 5
• 6) If applicable, has the rear tailgate failed to extend fully at any point leading up to the low battery issue? YES (give details) / NO
• 7) Are any accessories installed to the vehicle (either through the OBD port or hard wired ie: such as dash cameras)? YES (give details) / NO
• 8) Note any other information - ask the customer if they have any additional comments they feel may be relevant to the factors leading up to the fault

DIAGNOSTICS AND REPAIR ACTIONS IF LOW BATTERY WARNING INDICATOR ILLUMINATED

PINPOINT TEST A : INITIAL CONSULTATION - IMMEDIATE VEHICLE HISTORY PRIOR TO LOW BATTERY WARNINGS

PINPOINT TEST B : REFLASH MODULES

IQ/BATTERY DRAIN INVESTIGATION TESTS

In cases where the customer reports a low battery warning on a vehicle indicating a drain on the battery (and where the battery drain has NOT been detected by the quiescent drain test REFER to:Quiescent Drain (414-00 Battery and Charging System - General Information, Description and Operation).), a more thorough investigation may be required to identify the root cause of the battery drain

Print out the test plan and user guide form (below) and follow the battery drain investigation procedures. There are seven sets of tests, each set comprises three task lists. Not all seven sets of tests needs to be completed on every vehicle, this is a list of actions designed to prompt a vehicle failure. If a failure is detected, do not continue with the remaining sets, connect a manufacturer approved battery support unit to prevent the battery going flat and raise a Technical Assistance (TA) request immediately. If the vehicle is only available for a reduced amount of time, complete as many sets as possible before the return of the vehicle

READ NEXT: