These instructions apply to the Peugeot Partner Mk2 (B9) 2008-2018.
For other models, please choose your vehicle here.
Short answer: if your Peugeot Partner B9 (2008–2018) has electrical gremlins or won’t start after a battery change, a BSI (body computer) reboot often clears desync-type faults: close the doors, remove the key, wait about 3 minutes, disconnect the battery for ~15 seconds (longer if needed), reconnect, then switch the ignition on and wait a minute before starting. This is a widely-used owner/auto-electrician recovery, not an official Peugeot handbook procedure — and it will not fix a flat or wrong-spec battery, a blown fuse, or a failed BSI.
What the BSI Is and Why It Plays Up After a Battery Change
The BSI (Built-in Systems Interface) is the Partner’s central body computer. It needs to power down cleanly; if the battery is disconnected while it is still “awake”, or reconnected the wrong way, the modules can desynchronise. The result is classic post-battery symptoms: no-start, dead central locking, windows or wipers not working, or warning lights that won’t clear. A controlled reboot resyncs everything — but only where the cause is a desync, not a hardware or supply fault.
The Handbook Basics (Do These Every Time)
- Before disconnecting: switch the ignition off and wait two minutes so the systems power down.
- Remove the negative (−) terminal first; on reconnecting, fit the positive (+) first and the negative last.
- On reconnecting: switch the ignition on and wait one minute before starting, so the electronics re-initialise. See our battery disconnect guide for the full safe method.
BSI Reboot (Owner-Reported Recovery)
Not a printed factory procedure — the reboot Peugeot owners and auto-electricians use to clear post-battery desync faults. Timings vary by van and condition:
- Open the bonnet and lower the driver’s window first (in case central locking drops out), and keep the key with you, not in the cabin.
- Switch off all electrical equipment, remove the ignition key, and close all the doors.
- Wait about 3 minutes without touching the van, so the BSI goes to sleep.
- Disconnect the negative battery terminal for about 15 seconds (leave it a few minutes if a short attempt doesn’t help), then reconnect it, keeping the doors closed.
- Reach through the open window and switch the headlights on for a few seconds to gently wake the BSI, then turn them off.
- Switch the ignition on, wait a minute, then start the engine.
Afterwards, restore anything the disconnection cleared: the clock, the radio security code (if fitted), re-synchronise the remote if it no longer locks the van, and re-initialise the electric windows if they lost their one-touch function.
If the Reboot Doesn’t Fix It
A reboot only cures a body/BSI desync — not every no-start. If the van still won’t start or the faults remain, check the basics first: the battery (charge, terminals, correct spec) and the starting-circuit fuses, which can blow during a bad disconnection. If it still fails, or the BSI itself is damaged (burnt relay, corrosion), have it read and repaired by a Peugeot specialist. This is an owner information guide, not a substitute for a proper wiring/BSI diagnosis when faults persist.
Frequently Asked Questions
Why won’t my Peugeot Partner start after changing the battery?
Often the BSI desynchronised because the battery was disconnected while awake or reconnected poorly. A BSI reboot (doors closed, key out, wait ~3 minutes, disconnect ~15 seconds, reconnect, wake with the headlights, then start) frequently clears that — but a flat or wrong battery, a blown fuse or a starter fault won’t be fixed by a reboot.
Is a BSI reset safe to do myself?
Generally low-risk if you follow the battery method correctly — it’s a controlled power-down and reconnect. Keep to the terminal order, lower the driver’s window first in case the locking drops out, and if the van is under warranty or you’re unsure, use a specialist.
Do I need a diagnostic tool for a BSI reset?
No. The reboot is done with the battery terminal and the ignition. A tool is only needed to read stored codes if a fault remains afterwards.
My central locking / windows / wipers stopped after the battery — same fix?
Yes, those are typical BSI desync symptoms. Do the reboot, then re-sync the remote and re-initialise the windows if needed.
The reboot didn’t work — what now?
Check the starting-circuit fuses and the battery (charge and correct type) first. If it still won’t start, the BSI may have internal damage and needs a specialist.
If a specific fault code is stored, look it up on our sister site autodtcs.com to see what it points to before spending money.
Independent guide — not affiliated with Peugeot. Always follow your official service manual and safety precautions. Read our full disclaimer.