These instructions apply to the Subaru Forester Mk2 (SG) 2002-2008.
For other models, please choose your vehicle here.
If your second-generation (SG) Subaru Forester’s keyless remote has stopped working from a distance, or the little LED no longer lights when you press a button, the transmitter battery is almost certainly flat. It is a standard coin cell you can change in a couple of minutes — but on the SG Forester there is one extra step afterwards: the remote has to be re-synchronised with the car.
Signs the battery is weak
As the cell runs down, the remote’s range shrinks and the LED stops illuminating when you press a button. Replace the battery as soon as you notice either sign.
Replace the battery
- Remove the two screws on the back of the remote case with a Phillips screwdriver.
- Separate the two halves of the case.
- Lift the old battery out of the holder.
- Fit a new CR2032 cell (or equivalent), with the positive (+) side facing up.
- Clip the back half of the case on and reinstall the two screws.
Keep dust, oil and water off the board while it is open, and take care not to damage the printed circuit board.
Re-synchronise the remote
After the battery is replaced, the transmitter must be synchronised with the keyless-entry control unit or it will not operate the locks:
- Press either the LOCK/ARM or the UNLOCK/DISARM button six times to synchronise the remote.
- Test the remote by locking and unlocking the car.
Frequently asked questions
What battery does the SG Forester remote take? A CR2032 coin cell, fitted positive-side up.
My remote still doesn’t work after a new battery. On the SG Forester a fresh battery alone is not enough — press LOCK/ARM or UNLOCK/DISARM six times to re-synchronise it with the car. If it still fails, the remote may need re-programming into the system.
Does changing the battery erase the remote’s code? No — the code is stored in the car’s control unit, not the remote. You only need to re-synchronise, not re-program, after a battery change.
Adding or replacing a remote entirely? See how to program a Forester keyless remote.
Need to look up a warning light or trouble code on your Subaru? Our sister site autodtcs.com covers diagnostic trouble codes.
Independent guide — not affiliated with Subaru. Always follow your official service manual and safety precautions. Read our full disclaimer.