Peugeot Check Engine Light Stays On | Engine System Faulty

Does your Peugeot have a rough idle, won’t accelerate, won’t the check engine light stay on, and won’t the car start? Learn how to fix it by following the procedures below.

An illuminated Peugeot check engine light means a malfunction of the engine or emission system. A faulty spark plug, ignition coil, mass airflow sensor, oxygen sensor, or a loose gas cap often causes this problem.

In addition to the Peugeot check engine light staying on, you will get an Engine management system fault message displayed on the dashboard on newer models.

Symptoms

Pay attention to how your engine is running. Below is a list of possible symptoms that you may notice.

• Rough idle,
• Engine judder under acceleration or lack of power.
• The Peugeot check engine light stays on, and the car won’t start.
• The car won’t accelerate.
• Peugeot check engine light flashing.

The BC display may also show messages regarding the engine operation. You can use a YOUCANIC Full System scanner to diagnose your Peugeot check engine light via the OBD port under the dashboard. All 2000 and newer Peugeots have an On-Board Diagnostic (OBD) computer.

Peugeot Check Engine Light Meaning

Here are some of the usual combinations.

• It is a flashing check engine light with a Catalytic Converter Fault message displayed on the BC. The engine shakes and runs rough. This is a definitive sign of a misfire caused by bad spark plugs or faulty ignition coils. Do not drive the car, as this will cause damage to the catalytic converter.
• Constant check engine light – The engine is running fine. In most cases, this is caused by emission control system issues. It will probably be either faulty O2 sensors or a worn-out catalytic converter. A loose gas cap can also cause it.
• The BC displays a constant check engine light with a Depollution system faulty message. The engine is running rough. Now, this is a tricky one. Scan for codes; you will probably get P0300 and P1340 codes. This is described as a severe misfire on cylinders 1, 2, 3, or 4. This is misleading, as the usual problem is with one of the camshaft position sensors. Further diagnostic by a mechanic is required.
• Constant check engine light with Engine fault: repair needed message is displayed on the BC. The engine is running fine. This can be a sign of boost or fuel pressure system-related problems.
• Constant check engine light with Engine fault: repair needed message is displayed on the BC. A high-pressure fuel pump is often a common cause if the engine has a rough idle. If it idles fine but lacks power and poor acceleration, there is a large boost leak, or you could have a clogged catalytic converter.

Modern THP engines have a high-pressure fuel injection system, turbocharger, variable valve timing, and variable valve lift.

Common Problems

• Ignition Coil – A broken ignition coil pack assembly will cause a misfire and a flashing check engine™ light. Older Peugeots equipped with non-turbo four-cylinder engines are more prone to this problem.
• Camshaft Position Sensor – Faulty camshaft position sensors on VVT and THP engines usually cause a misfire.
• Variable Valve System – Newer engines have a variable valve lift system. The usual failure point is the electric stepper motor or eccentric shaft position sensor. This can cause poor throttle response or even a non-starting engine.
• Fuel Pump – High-pressure fuel pumps can fail on newer, turbocharged THP engines. It will cause a very rough idle.
• Turbo – Turbocharged THP engines have a recirculation valve between the turbocharger and intercooler. It can suffer from a broken membrane. This will cause a boost leak and a noticeable power loss.
• Fuel Quality – Diesel HDI is very sensitive to fuel quality. Low-quality diesel fuel can damage the fuel pump or injectors. The fuel filter must be replaced at regular intervals. Diesel injection faults will cause driveability issues under hard load (i.e., driving uphill).
• EGR Valve – Diesel HDI engines can suffer from faulty EGR valves. Rough idle, engine pinging or smoke from the exhaust are some of the symptoms. Also, the DPF exhaust filter can get blocked over time.

Whatever the combination, you will need a code reader or a scan tool to understand the problem better. Without it, you can only guess the source of the problem. This hit-and-miss method might end up as a wild goose chase.

How to Diagnose Peugeot Check Engine Light

1. Plug a YOUCANIC Scanner into the OBD2 port. Most Peugeot vehicles are under the steering wheel in the driver’s side footwell. However, some models have OBD2 ports located in unusual places. In Peugeot 407 or 607, look in the armrest compartment. In Peugeot 307, 308, or RCZ, there is a small matt-covered slot at the bottom of the central console, in front of the gearbox lever. Remove this matt to reveal the port. In 508, take out the ashtray in front of the gearbox lever.
2. Turn the ignition ON so your dashboard illuminates, but don’t start the engine.
3. Allow your YOUCANIC scanner to turn on. Press Enter, then Read Codes.
   
4. Write down the codes and do online research on what each code means and possible causes.
   

How to reset the Peugeot check engine light?

To reset the Peugeot engine management light, first, you must fix the problem that triggered the fault codes. Then watch the video or follow the instructions below on resetting the check engine light.

Next, use the YOUCANIC scanner to clear the fault codes via the OBD-II port under the dashboard.

1. Connect an OBD2 scanner to the port under the dashboard.
2. Turn on the ignition.
3. Press enter on your scanner. Scroll down to Erase Codes—press enter.
4. Turn the ignition off and wait for several seconds.
5. Turn the engine on and check if the check engine light will appear again.

Frequently Asked Questions

We hope you find the Peugeot Check Engine Light Stays On | Engine System Faulty guide helpful. Check these troubleshooting and repair guides for more help on your Peugeot.