A Range Rover That Starts on Monday and Is Dead by Friday
The car arrives on a flatbed, and the story that comes with it barely changes: it ran perfectly on the weekend, sat in a Walnut Creek driveway for four days, and then would not even light the dash. The battery tests fine once it has been charged. Nothing on the dash warned anybody. Something on board is quietly drinking current while the car is parked, and on a Land Rover that is rarely the battery's fault.
A parked car is never completely switched off
Lock the doors and the electronics do not all stop. Alarm sensors, the telematics module, the keyless entry receivers, and the body control module stay partly awake, then hand off to a low-power state once the car decides nobody is coming back. On a healthy modern European car that settled draw is small — well under 50 milliamps, which a good battery can carry for weeks.
A parasitic draw is what happens when one of those modules never gets the message. It stays at full power, pulling perhaps 300 or 500 milliamps all night, and a 90-amp-hour battery that should last two weeks is flat in three days.
The sleep sequence is also staged. Some modules drop out within minutes, others take far longer, and the last of them can keep going for the best part of an hour. Any measurement taken before that process finishes is meaningless, and that is a common reason a quick check at a parts counter comes back clean.
Range Rovers and Discoverys give a draw more places to hide
A late Range Rover carries dozens of control units. Air suspension, the infotainment head unit, the keyless-entry antennas, a terrain response controller, heated everything. Every one of them has a sleep routine, and every one of them is a candidate.
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The other reason these cars show it first is simple arithmetic. More standby load means less margin, so a draw that a simpler car would absorb for a week kills a Land Rover over a long weekend.
Short local driving hides the problem until it doesn't
The AAA Foundation for Traffic Safety found that American drivers covered an average of 28.6 miles a day in 2025. A run down Ygnacio Valley Road and back puts very little charge into a battery, because the alternator spends the first part of the trip replacing what starting the engine just used.
So a mild draw and a short commute cancel each other out until the pattern changes. Holiday travel, a week away, a stretch of rain where the car does not move — then the car that always started suddenly doesn't.
Finding it means watching the car fall asleep
Guessing is expensive here, and swapping a battery on spec fixes nothing. The real test is an ammeter in series with the battery, the car locked and left alone until the modules settle, then a steady reading over the next half hour. If the number stays high, fuses come out one at a time until it drops, and the circuit behind that fuse becomes the suspect.
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Factory-level software matters just as much. The right factory scan tool can interrogate the network directly, watch each controller report its state, and show which one is refusing to go quiet, which turns a fuse-pulling marathon into a short conversation with the car.
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The usual culprits are boring, and that is good news
Most of what we find is cheap once it is identified. A tailgate latch microswitch that thinks the tailgate is open. A failed antenna that keeps the keyless system hunting. An aftermarket dash camera wired into a circuit that never switches off. Water in a connector under the seat, which corrodes a pin and leaves a module half-powered.
Check the software too. Some sleep faults are a known calibration problem and clear with an updated module program, no parts involved.
What we almost never find is a battery that was simply old. That gets ruled out in the first ten minutes with a conductance test, and when the battery passes, the hunt moves to the circuits.
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Three things you can tell us before the car arrives
Count the days. A car that dies in two is carrying a far heavier draw than one that dies in ten, and the number narrows the search before the hood is even opened.
List anything added recently. Dash cameras, tracking devices, remote starters, subwoofers and trailer wiring are responsible for a large share of what we find, and knowing one was fitted last month saves an hour of testing.
Check where the key lives overnight. Keyless systems keep hunting while a fob sits within range, so a key hung on a hook six feet from the garage wall can hold part of the car awake every night. Moving it to the far side of the house costs nothing, so try that first.
Frequently Asked Questions
Q: How long should a Land Rover sit before the battery goes flat?
A: A healthy car with a good battery should start after two or three weeks parked. If yours struggles after four or five days, have the draw measured.
Q: Will a battery charger fix a parasitic draw?
A: No. A trickle charger keeps the car usable, but it only covers up the fault. The draw is still there and it will keep shortening the battery's life.
Q: Can a new battery cure the problem?
A: Only if the old battery was genuinely worn out. A fresh battery on a car with a 500-milliamps draw will go flat too, just a little slower.
Book a Draw Test Before the Holidays
If your Land Rover has been needing a jump start after a few days parked, bring it to us at 2008 Mount Diablo Blvd in Walnut Creek and let us measure it properly. Details on the shop and the work we do are at mserviceinc.com.
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