These instructions apply to the Isuzu D-Max Mk2 (TF) 2012-2020. For other models, please choose your vehicle here.
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The Isuzu D-Max (Mk2/RT50, 2012–2020) came two ways: base and work-spec trucks use a conventional bladed key in a turn ignition, while higher trims get the Passive Entry & Start System (PESS) with a proximity fob and a push-button start. A flat fob battery affects each set-up differently, so check the dash for an ignition barrel or a START/STOP button before assuming the worst.
Start the Truck When the Fob Is Dead
On a turn-key D-Max the coin cell only powers the remote buttons; the immobiliser chip is in the blade and needs no battery, so the truck starts as always:
- Insert the cut key into the ignition barrel on the column.
- Turn to crank — the D-Max starts normally.
On a PESS truck with a START/STOP button, the proximity fob can still be read up close even when the cell is flat — this is the official Isuzu low-battery method:
- Get in (mechanical-key steps below) and sit in the driver’s seat with the door shut.
- Press the brake pedal fully and hold it.
- Hold the proximity fob against the START/STOP button.
- With the brake down, press START. The D-Max cranks and starts.
Unlock With the Emergency Key
A dead fob will not unlock by radio, so use the blade.
- On the turn-key truck use the cut key; on the PESS fob, press the release button and pull the emergency blade out.
- Insert it into the driver’s door lock cylinder.
- Turn to unlock; the alarm may sound until the ignition is on.
About the Immobiliser
The D-Max immobiliser reads the transponder in your key on each start, a passive check that draws nothing from the coin cell. That is why the turn-key truck starts on a dead remote and the PESS truck still reads the proximity fob held to the button. A crank-but-no-run or a key warning that survives a fresh cell points at the key or its module, not the coin cell.
Replace the Coin Cell
The D-Max fob uses a 3V lithium coin cell — most commonly a CR2032, with some takes on a CR2025. Read the old cell to be sure.
- Pull the emergency blade out (or open the remote fob), then ease the case halves apart with a small flat screwdriver — pad the tip with tape to avoid marking the case.
- Note the old cell’s number and fit the matching new one positive (+) side the same way, by the rim.
- Click the case shut and test lock/unlock at the truck.
Frequently Asked Questions
Can I start my D-Max with a dead fob? Yes. Turn-key trucks start on the cut blade; PESS trucks start by holding the proximity fob to the START/STOP button with the brake down.
Which battery does the D-Max fob take? A 3V lithium coin cell, usually CR2032 (some CR2025) — check the old one.
How do I tell if my D-Max is PESS or turn-key? A START/STOP button means PESS proximity; an ignition barrel on the column means a conventional key.
How long does the PESS fob battery last? Roughly one to two years, as the proximity fob is constantly listening for the truck.
Do I need to reprogram after a battery change? No. The coin cell only powers the remote; swapping it does not erase the key.
If a warning light stayed on after you drove off, you can decode the exact fault on our sister site autodtcs.com to check whether it relates to the key or immobiliser.
Disclaimer: The information on this page is provided for general guidance only. Always follow your official service manual and safety precautions when working on your vehicle. We are not responsible for errors, omissions, or any damage resulting from the use of this information.
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