Flickering Engine Light and Rough Idle on Peugeot 208 II

A flickering engine light plus a rough idle is a message, not a nuisance

If your Peugeot 208 II is shaking at idle and the check engine light flickers on and off, the ECU is usually reporting an active misfire. On these cars, especially the 1.2 PureTech petrol and BlueHDi diesels, that can come from ignition, fuel, air, or timing. A steady light says store this and check soon; a flickering or flashing light says stop making it worse. I would treat it as urgent until you have the fault codes.

Most likely causes on a 208 II

Start with the basics, but keep Peugeot-specific weak points in mind:

• Ignition misfire: worn spark plugs, a failing coil pack, or a bad coil connector. This is very common on 1.2 PureTech engines.
• Fuel delivery: dirty or leaking injectors, low fuel pressure, a tired high-pressure fuel pump, or a restricted diesel fuel filter.
• Air and vacuum leaks: split intake hoses, a leaking PCV/breather, purge valve, or intake gaskets. These lean out the mixture and make idle rough.
• Sensor faults: lambda/O2 sensor, MAP or MAF sensor, coolant temperature sensor, or crankshaft/camshaft position sensor. Live data matters more than the part name.
• Timing and oil issues: on 1.2 PureTech, the wet timing belt can degrade, shed fibres, and block the oil pickup. That affects cam timing and oil pressure, and it can cause misfires. Do not ignore this.
• Diesel-specific: clogged EGR valve, injector correction values out of spec, glow plug faults, or DPF pressure issues.

What to check first

Before replacing parts, get a Peugeot-compatible scan tool (DiagBox or a good OBD2 reader that shows live data) and read the stored and pending codes. Typical ones are P0300-P0304 for misfire, P0171/P0172 for fuel trim, P1336-P1339 for Peugeot misfire codes, and P0011/P0016 for timing. Then:

• Check oil level and condition; on a PureTech, inspect the wet belt and oil pickup for debris.
• Test spark plugs and coils; swap a coil to another cylinder and see if the misfire follows.
• Check injector operation and fuel pressure; on diesel, look at injector correction values and leak-off.
• Smoke-test the intake for vacuum leaks, and inspect breather hoses and the purge valve.
• If the misfire is persistent, run a compression and leak-down test before condemning sensors.

Is it safe to keep driving?

If the light is flickering or flashing, I would not keep driving normally. An active misfire dumps unburnt fuel into the catalytic converter, and that can turn an inexpensive repair into a very expensive one. If the car is only rough at idle, drive gently to your garage or a safe spot and get it scanned; avoid hard acceleration and long trips. Stop immediately if you have heavy shaking, loss of power, smoke, a strong fuel smell, or overheating. A steady check engine light is less urgent, but it still needs diagnosis soon. Your 208 II is telling you something - listen to it before it becomes a bigger bill.

This material is AI-generated and for informational purposes only — it does not replace an in-person diagnosis by a qualified mechanic.