How to Replace Ignition Coils 2004-2012 Volvo S40
Difficulty: Intermediate · About 60 min · Volvo S40
Replace an ignition coil on a 2004–2012 Volvo S40 after confirming which cylinder has a coil fault. Work on a cool engine and inspect the plug well and connector so a damaged spark plug, oil leak, or wiring issue is not mistaken for a failed coil.
Tools you will need
- 8mm socket
- 14mm wrench
- Ratchet and extensions
- Swivel adapter
- Flat blade screwdriver
- Compressed air or hand blower
- Torque wrench
- Safety glasses
Parts and supplies
- Ignition coil matched to the engine and cylinder
- Spark plug if testing shows it is worn or damaged
Steps
Identify the affected cylinder
Read the diagnostic codes and confirm the misfire follows the suspected coil before replacing it. Let the engine cool, switch off the ignition, and remove any engine cover or intake piece required for access.
Clean around the coil
Disconnect the coil connector and move the wiring clear. Blow or brush debris away from the plug well before removing the coil so dirt cannot fall into the cylinder.
Remove and inspect the coil
Remove the coil retaining fastener and pull the coil straight out by its body. Check the boot and plug well for oil, moisture, carbon tracking, or a damaged connector that could cause the same symptom.
Install the replacement coil
Compare the replacement with the removed part, seat its boot squarely over the spark plug, and tighten the retaining fastener to the vehicle specification. Reconnect the electrical plug until its lock engages.
Reassemble and confirm the repair
Reinstall the engine cover and any removed intake components. Start the engine, verify it runs smoothly, and recheck for misfire codes or warning lights after a short test drive.
Check your vehicle’s repair manual for exact specifications and fit.