The largest online repair guide library for every car

About us
Contact support
FAQ
Sign up
Sign in

2019 Discovery HSE: Persistent Low Battery Warning & Start-Stop Malfunction

0

Ryan M. · rep 0 · May 22, 6:32 AM · 1 replies · solved · Question

Vehicle: 2019 Land Rover Discovery HSE

Hey everyone,

I'm having a really frustrating issue with my 2019 Land Rover Discovery HSE. For the past few weeks, I keep getting a 'Low Battery' warning message on the dash, especially after the car sits for a day or two.

What's even more annoying is that the start-stop system has completely stopped working. It just says 'Start-Stop Not Available' almost every time I drive. I had the main battery tested at a local auto parts store, and they said it was 'good' but maybe a bit low on charge. I even tried trickle charging it overnight, but the warning eventually comes back.

Could this be a parasitic drain, or something more serious with the charging system or a module? I'm worried about getting stranded. Any ideas on what to check or if this is a common problem?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 6:32 AM

0

ClearTheCode admin answer:

  1. Battery Health & Charging System: Even if a battery tests "good," its capacity might be diminished, especially in modern vehicles with high electrical demands. The Battery Monitoring System (BMS) is very sensitive.

    • Check Battery Terminals: Ensure they are clean and tight. Corroded or loose terminals can impede proper charging and discharge.
    • Alternator Output: Have a shop test the alternator's output under load to ensure it's charging correctly (typically 13.5-14.5V). A weak alternator won't fully charge the battery.

  2. Parasitic Drain: This is a common cause of low battery warnings. Something is drawing power when the vehicle is off.

    • Diagnosis: A technician can perform a parasitic draw test using an ammeter to isolate the circuit or module responsible. Common culprits include infotainment modules, telematics units, or even a faulty door switch keeping a module awake.

  3. Battery Monitoring System (BMS) Reset/Fault: The BMS needs to be correctly calibrated to the battery. If a new battery was installed without resetting the BMS, or if the BMS itself is faulty, it can give incorrect readings.

    • DTCs: Scan for Diagnostic Trouble Codes (DTCs) using an generic OBD-II scanner, but a Land Rover specific tool will be more comprehensive. Look for codes related to battery voltage (e.g., P0562 - System Voltage Low), charging system, or specific module communication errors.

  4. Start-Stop System Logic: The start-stop system is designed not to engage if the battery charge is below a certain threshold, or if other conditions (like cabin temperature, engine temperature, or specific electrical loads) are not met. A persistent low battery warning will definitely disable it.

  5. When to See a Shop: If you've checked the basic battery connections and the issue persists, it's best to have a qualified Land Rover specialist diagnose the problem. They have specific diagnostic tools (like SDD or Topix JLR) that can read all modules, perform battery resets, and accurately pinpoint parasitic drains or faulty components. Ignoring a persistent low battery warning can lead to unexpected breakdowns and potential damage to sensitive electronic modules.

Menu

Help & account