What Do Peugeot 308 Warning Lights Mean? Service and Gauge Guide

The 308's digital instrument panel shows a lot more than speed and revs. Alongside the warning lamps there are status readouts for servicing, oil level, engine temperature, AdBlue (on diesels) and, on plug-in hybrids, power flow and battery charge. Knowing what is normal makes it much easier to spot when something isn't.

This guide walks through those readouts on the third-generation 308 hatchback and SW (2021 on), plus the manual instrument test and the lighting dimmer. We've used the official Peugeot 308 owner's handbook as our reference. Looking for a specific warning lamp? Try our red or orange warning guides instead.

Service Indicator

The service indicator tells you when the 308 needs maintenance. Service information is shown on the instrument panel in distance (kilometres or miles) and time (months or days), and the alert is triggered by whichever limit is reached first.

Types of Service Indicator and What They Mean

Distance recorder line: shows the distance driven since the service was due or its deadline passed, preceded by a "-" sign.

Alert message: tells you how many kilometres or how much time remain until the next service is due.

Maintenance spanner (temporarily, when the ignition is switched on): the next service is between 1,000 and 3,000 km away.

Maintenance spanner (on steadily with the ignition on): the next service is less than 1,000 km away. Have the car serviced as soon as possible.

Flashing maintenance spanner: the service is overdue. Have the car serviced as soon as possible.

What to do:

Act according to the indicator: based on the type of alert, assess your car's maintenance needs and book a service if necessary.

Resetting the service indicator: the indicator can be reset after every service. If you service the car yourself, follow the steps below.

To reset it:

• Switch off the ignition. This is the starting point for the reset.
• Press and hold the button on the end of the lighting control stalk.
• Switch on the ignition without starting the engine. A temporary display window opens for the reset.
• Wait for the countdown: a countdown starts on the display and runs until the indicator is reset.
• Wait for the confirmation: when "=0" is shown, the reset is complete and a confirmation message appears.
• Release the lighting stalk button. The spanner symbol disappears.

If you run into any problems or need more information, contact a PEUGEOT dealer or qualified workshop.

Service Information Reminders

Automatic reminders: the 308 reminds you automatically when a service is approaching, with alerts on the instrument panel and the touchscreen.

Manual check: checking the service status regularly in the "Diagnostics" section helps you spot any maintenance need early and act in good time.

Engine Oil Level Indicator

Peugeot 308 Engine Oil Level Indicator and Related Warnings

The engine oil level indicator helps you keep an eye on your 308's engine oil, which is critical for a healthy engine. There are two main types of warning: low oil level and oil level gauge fault.

Low Oil Level Warning

Conditions: the level check is only valid when the car is on level ground and the engine was switched off at least 30 minutes earlier.

Warning: the Service warning lamp comes on with an audible signal and the message "Oil level incorrect" appears on the instrument panel.

What to do: if the level is low and the dipstick confirms it, you must top up to avoid engine damage.

See the relevant section of your owner's handbook for more on checking levels.

Oil Level Gauge Fault Warning

Warning: the message "Invalid oil level measurement" appears on the instrument panel.

What to do: contact a PEUGEOT dealer or qualified workshop. With the electric gauge faulty, the oil level may no longer be monitored correctly.

Manual check: while the system has a fault, check the oil level with the dipstick in the engine compartment.

These warnings are vital for keeping the engine properly lubricated and making it last. Pay attention to them, and if you have a problem, contact a PEUGEOT dealer or qualified workshop for quick, professional help.

Coolant Temperature Gauge

Peugeot 308 Coolant Temperature Gauge and Related Warnings

The coolant temperature gauge helps you monitor the engine's temperature, preventing overheating and keeping the engine healthy. The gauge shows two zones: normal temperature (zone A) and excessive temperature (zone B).

Normal and Excessive Temperature Warnings

Normal temperature (zone A): the engine temperature is normal and acceptable.

Excessive temperature (zone B): if the gauge reaches zone B, the engine temperature is too high. The related warning lamp and the red STOP warning lamp come on, and you get a message and an audible signal.

What to Do If the Engine Overheats

Stop safely: you must stop the car in the safest conditions possible. Pull over safely, taking traffic and road conditions into account.

Wait a few minutes: rather than switching the engine off immediately, wait a few minutes to help it cool down a little.

Open the bonnet carefully: after switching off the ignition, open the bonnet with care. The engine compartment can be very hot.

Check the coolant level: a low coolant level or a leak can indicate a serious problem.

Get it checked: if there is a problem with the coolant or the engine keeps overheating, take the car to a PEUGEOT dealer or qualified workshop.

Cooling System Maintenance

Regular checks: check the coolant level and condition regularly.

Level check: if the coolant level is low, top up with the correct coolant.

See your owner's handbook for more information. Looking after the cooling system prevents overheating and extends engine life.

AdBlue® Range Indicators (BlueHDi)

Peugeot 308 BlueHDi AdBlue® Range Indicators and Warnings

Peugeot 308 BlueHDi models use a Selective Catalytic Reduction (SCR) emission control system and a Diesel Particulate Filter (DPF) to treat exhaust gases, and these systems need AdBlue® fluid to work. Here's how the AdBlue® level and its warnings work:

AdBlue® Reserve Level and Warnings

Below the reserve level (2,400 to 0 km): when the AdBlue® reserve drops, a warning lamp comes on every time you switch on the ignition and the estimated remaining range is shown.

When the AdBlue® tank is empty: the starting prevention system kicks in, and the engine can't be started until the minimum level of AdBlue® has been added.

Manual display: when the range is more than 2,400 km, it isn't shown automatically. You can find it in the touchscreen's "Settings > Vehicle" application, under "Safety > Diagnostics".

What to Do When AdBlue® Is Running Low

Between 2,400 and 800 km: messages and warning lamps remind you to top up.

Between 800 and 100 km: there is a risk the engine won't start, so topping up with AdBlue® is important.

100 km and below: the risk of the engine not starting increases.

At 0 km: you must add at least 10 litres of AdBlue® to the tank before the engine can be restarted.

SCR Emission Control System Fault

Fault detected: the message "Emissions fault" appears and the related warning lamps come on. If the fault is temporary, the warning may go out on the next journey.

Fault confirmed during the permitted driving phase: between 1,100 km and 0 km, if the fault indication stays on permanently, the SCR fault is confirmed. Have the car checked by a PEUGEOT dealer or qualified workshop.

Starting prevented: the message "Emissions fault: Starting prevented" appears. You must contact a PEUGEOT dealer or qualified workshop.

The SCR system and AdBlue® are critical for keeping the 308 BlueHDi within emissions standards. Check the AdBlue® level regularly and top up when needed, and if any warning lamp comes on or you think the system isn't working properly, see a qualified workshop straight away.

Power Indicator (Plug-in Hybrid)

The power indicator on the 308 plug-in hybrid shows the power being used and how energy is being managed in real time, helping you drive more efficiently. It is split into three main zones: POWER, ECO and CHARGE.

POWER Zone

The POWER zone shows when the petrol engine and electric motor are working together under high power demand.

When it's active: in more dynamic driving and situations that need high performance. With the needle here, the car delivers maximum power.

Driving style: this zone comes into play under hard acceleration or on steep climbs.

ECO Zone

The ECO zone shows the most efficient use of energy, with optimal use of the petrol engine and the electric motor.

When it's active: the needle is here when driving on the electric motor and when the petrol engine is being used efficiently.

Energy management: you can adapt how you accelerate to stay in electric mode, saving fuel and making the most of the electric motor.

CHARGE Zone

The CHARGE zone shows that energy is being recovered to partially recharge the traction battery.

When it's active: when slowing down, for example when you lift off the accelerator or brake.

Regenerative braking: the car's kinetic energy is converted into electrical energy, partially recharging the traction battery.

Charge Level Indicator (Plug-in Hybrid)

This indicator shows the traction battery's charge level and the distance you can cover on that energy, telling you how far you can go in electric mode and helping you manage energy.

Charge Level Indicator Features

Always displayed: when the car is switched on, the traction battery's current charge level and the estimated electric range are shown on the instrument panel at all times.

Variable range: the range shown can change depending on how the car is used (driving style and speed), the outside temperature and the use of comfort equipment.

Driving style and speed: faster or more aggressive driving uses more energy and can reduce the range.

Outside temperature: very cold or very hot weather can affect battery performance and change the range.

Comfort equipment: equipment that draws extra power, such as heating, cooling and the radio, can affect the range when in use.

Managing Energy Effectively in Electric Mode

Energy efficiency: use the indicator to optimise energy use and get the most from electric mode.

Planning: charge level and range information is key when planning long journeys or covering a particular distance in electric mode.

Manual Test

The Peugeot 308 Manual Test Function

The manual test lets you check the 308's various indicators and alerts, giving you a full picture of the car's status. It's easy to reach from the touchscreen.

Running the Manual Test and What It Shows

How to start it: open the Settings > Vehicle touchscreen application, then select Safety > Diagnostics to run the test.

Information Shown on the Instrument Panel

Tyre pressures: the current pressure of the car's tyres, critical for road safety.

Engine oil level: shown depending on the engine type, and important for engine health.

Next service due: helps you keep maintenance on schedule.

Driving range related to AdBlue® and the SCR system (BlueHDi diesel): information on the AdBlue® level and SCR system status, which matters for diesel emission control.

Active alerts: any warnings or situations needing attention.

Automatic display: this information also appears automatically every time you switch on the ignition, so you always know the car's current status.

Peugeot 308 Odometer

The odometer measures the total distance the 308 has covered since it was first registered. It tells you a lot about the car's use and condition and plays a key role when buying a used car or planning maintenance.

Odometer Features and Use

Display: with the ignition on, the total distance is shown continuously on the instrument panel, and it stays on for 30 seconds after the ignition is switched off.

Door open and locking: it is also shown when the driver's door is open and when the car is locked or unlocked.

Changing the distance units: you can switch between kilometres and miles when travelling abroad, from the touchscreen's configuration settings while the car is stationary.

Odometer on Plug-in Hybrid Models

Access: on plug-in hybrid models, the odometer can only be reached through the trip computer.

Trip computer information: the trip computer gives more detailed driving data, including energy consumption, driving efficiency and overall performance.

Lighting Dimmer

The lighting dimmer lets you manually adjust the brightness of the instruments and controls to suit the light outside. It's very useful for reducing eye strain and making night driving more comfortable.

Using and Adjusting the Lighting Dimmer

Settings menu: the dimmer is easy to configure from the touchscreen's Settings menu.

Brightness: go to "Settings > Brightness" and use the slider in the "Cockpit" category to set the brightness you want for the instrument panel and other controls.

When to Use It

Night driving: dimming the cabin lighting at night helps your eyes adjust to the darkness outside and reduces eye strain.

Changing light conditions: adjust the instrument panel and controls lighting to suit the weather or light level outside.

Key Points to Remember

• A flashing or red service, oil or temperature readout always takes priority over everything else on the panel
• Check the oil level with the dipstick if the electronic gauge reports a fault, rather than relying on the gauge
• Don't let a BlueHDi diesel run out of AdBlue: once the tank is empty, the engine won't restart
• Book your service when the spanner first appears rather than waiting for it to flash

For the warning lamps, see our 308 red warning lights, orange warning lights and green and blue indicator lamps guides, and learn your way around the screens in How to Check Peugeot 308 Warning Lights. For the car as a whole, read our Peugeot 308 review.

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