EXPERT IN AUTO PARTS
26 March 2026 (updated) Table of Contents
Peugeot 308 warning lights typically follow a traffic light priority system: red means pull over ASAP, orange means there is a fault to address soon, and green confirms that a system is active and working correctly. Knowing what each Peugeot dashboard warning light symbol means could prevent a minor fault from becoming an expensive repair, or worse, a breakdown on a busy road.
This guide covers every major warning light or indicator you are likely to see on the Peugeot 308 dashboard, including what it signals and precisely what to do when it appears.
Before working through each individual symbol, it is worth understanding how the colour-coding system works for Peugeot dashboard warning lights. The system is consistent across all modern Peugeot models, so the same logic applies whether you drive a Mk1 (2007–2013) or the more recent Mk3 308.
| Colour | Urgency | Recommended action |
|---|---|---|
| Red | Serious – potential danger | Pull over safely, switch off the engine, and seek assistance. |
| Orange/amber | Fault detected – not immediately dangerous |
Check as soon as possible; book a service promptly. Exception: a flashing amber engine light indicates a serious catalyst-damaging fault. |
| Green | Informational | No action is required – the system is working correctly. |
| Blue | Informational | Used to indicate that the high beam lights are activated or, in some models, that the engine is still cold (blue coolant symbol). |
Peugeot warning indicators that appear in red will often be accompanied by the STOP warning light, a message on the instrument panel, or an audible alert. Orange lights tend to appear on their own or alongside the service light, which helps you to narrow down the fault. If two warning lights appear simultaneously, (e.g. the ABS warning light and the brake system warning light) treat the situation as urgent regardless of the colour, as the combination often signals a more significant underlying fault.
Red lights demand your full attention. When any red light appears on the Peugeot 308, pull the vehicle to a safe place as soon as possible.
The Peugeot stop warning light is the most serious alert on the entire instrument panel. When this red icon illuminates (sometimes simply reading "STOP") it means a fault has developed that makes continued driving potentially dangerous. The light can be triggered by critically low oil pressure, overheating, brake system failure, or other serious faults.
Pull over safely, switch off the engine, and do not restart until the source has been identified. You may need to call for breakdown assistance. Consult the instrument panel message for further details and seek professional help.
This light signals a fault in the engine's lubrication system. It may mean that the oil pressure is critically low, the engine oil level has dropped dangerously, or the oil temperature has exceeded safe limits. Stop the engine immediately. Running an engine without adequate oil pressure causes severe, often irreversible internal damage within minutes.
Once safely parked and cool, check the engine oil level using the dipstick. If the level is very low, top up with the correct grade of oil gradually, checking the dipstick between additions to avoid overfilling. Too much oil puts excess pressure on seals and gaskets. However, topping up the oil will not fix faults such as blockages and system leaks.
When this light illuminates, it usually indicates that the cooling system temperature has reached a dangerous level. Allow the engine to cool completely before opening the bonnet. A known fault on the Mk2 Peugeot 308 is a faulty coolant temperature sensor that triggers this warning falsely. Numerous owners have reported pulling over expecting steam, only to find the engine perfectly cool.
In this particular case, replacing the sensor is a straightforward repair. If actual overheating has occurred, the root cause, such as a failed thermostat, leaking hose, or low coolant level, must be identified and resolved before driving again.
This light indicates a fault in the battery charging circuit. The most common cause is a faulty alternator that is no longer generating a charge to maintain the battery power. Checking the battery terminals for corrosion or loose connections is a sensible first step, as poor contacts can produce the same warning.
If the terminals are clean and tight and the light remains on, the alternator should be tested. A battery that is not being charged will eventually stop working altogether, so this light should not go ignored.
The brake warning light can indicate several faults, such as a low brake fluid level, a fault in the braking system itself, or a parking brake that has not released properly. If the light illuminates while driving and the parking brake has definitely been released, get the vehicle inspected without delay.
A low brake fluid level can indicate worn brake pads (which displace more fluid as they wear down) or a leak in the hydraulic circuit. Either way, a compromised braking system carries real safety implications and will result in an MOT failure under UK regulations.
The airbag warning light indicates a fault in the airbag system, also referred to as the supplemental restraint system. When this light stays on after startup, the airbag system may not deploy correctly in the event of a collision. This airbag light should never be ignored. The safety system relies on a network of sensors, clock spring connections, and pyrotechnic units, meaning that a proper diagnosis requires specialist diagnostic equipment.
Check that all the seat belts are properly connected, as a faulty seat belt pretensioner can sometimes trigger the airbag light. If the warning persists, book the vehicle into a garage right away.
This light illuminates when the control unit detects that a seat belt is not fastened. It applies to the driver and any passenger whose seat sensor detects weight. The supplemental restraint system requires all occupants to be belted in to function as designed.
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Orange/amber lights usually indicate a fault that needs attention but does not necessarily require you to stop immediately.
The engine management light signals that the engine's electronic control unit (ECU) has detected a fault. This could relate to the injection system, emission control system, sensors such as the oxygen (lambda) probe, or the diesel particulate filter (DPF) on diesel models. The way the light behaves tells you how serious the fault is:
On diesel 308 models, the emission control system is a frequent trigger. The DPF collects harmful soot from exhaust gases to reduce emissions. However, if it becomes critically full, the engine management light will appear. If the light remains on or you frequently undertake short journeys, active regeneration at a garage may be required.
A proper diagnosis requires an OBD-II scanner. Fault codes such as P023C (charge air cooler bypass valve) or those relating to the injection system will pinpoint the fault precisely.
If the ABS warning light remains on after the initial check when you start the engine, it means that there is a fault within the anti-lock braking system. The ABS warning disables the system, but your standard brakes continue to function normally. You can still stop the car, but the system that prevents wheel lock under heavy braking will be inactive. When combined with the red braking light, the electronic brake force distribution (EBD) system may have failed, which is a critical fault.
The most frequent cause on UK-registered 308 models is a faulty wheel speed sensor. During winter, road salt corrodes sensors and can cause the warning to appear intermittently or permanently. The ABS ring on the brake disc can also become damaged, causing the same result. A solid ABS light will cause your car to fail its MOT as the Driver and Vehicle Standards Agency (DVSA) classifies a confirmed ABS system fault as a major defect.
The brakes account for a large proportion of dangerous defect MOT failures in the UK. Addressing an ABS warning promptly is therefore both a safety and a legal matter.
BlueHDi diesel variants of the 308 use AdBlue fluid injected into the exhaust to reduce nitrogen oxide emissions. The AdBlue warning light communicates the status of the AdBlue tank:
AdBlue or diesel exhaust fluid is widely available at petrol stations and shops across the UK. It can easily be topped up via the dedicated filler cap. Failing to top up will prevent the engine from starting once it has been switched off as the system is designed to reduce emissions at a fleet-wide level and cannot be bypassed.
The maintenance light (a spanner symbol) is one of the more versatile indicators on the Peugeot 308 dashboard. It basically serves as a reminder, telling you when your next service is due. It behaves differently based on how much time is left:
The electric parking brake indicator has two distinct states. A fixed light simply means that the parking brake is applied. This is normal when the vehicle is parked. When the light appears on this preset light setting during driving, it likely means the brake has not fully released. In this case, applying and releasing the brake manually should resolve it.
A flashing parking brake warning light signals a malfunction in the automatic application or release mechanism. Park on level ground, as the brake may not be holding reliably. Temporarily restoring its function may be possible by carrying out the manual override procedure, which involves pressing and holding the electric parking brake button while pressing the brake pedal. If the light persists or the automatic functions cannot be reactivated, a diagnostic scan is required to select a system reset or identify the underlying fault.
This indicator means one or more tyres are below the recommended tyre pressures. On UK roads, where potholes and kerb strikes are common, a sudden loss of pressure is not unusual. Check all four tyres as soon as possible and inflate to the pressures shown in the owner's manual or on the label inside the driver's door frame.
Note that the correct pressures vary depending on load and speed as a fully laden car requires higher pressures than one with a single occupant. After correcting the tyre pressures, you will need to reset the light yourself via the infotainment menu.
On diesel 308 models, this light turns on briefly during startup as the glow plugs warm the engine for ignition. Once the light turn-off occurs, the engine is ready to start. If the light stays on during driving or the engine struggles to start on cold mornings, the glow plugs likely need replacement.
The fuel level warning light illuminates when the fuel level drops to approximately 30 miles of range remaining (this will vary depending on the driving conditions and engine type). Refuel as soon as possible. Running a diesel engine dry is particularly problematic as it can draw air and debris through the fuel system and potentially damage injectors.
| Warning light | Most common cause | Approx. UK repair cost |
|---|---|---|
| ABS warning light | Wheel speed sensor fault | £80–£200 |
| Engine management light | Lambda sensor, DPF issue, injection fault | £100–£500+ depending on cause |
| Brake warning light | Low brake fluid, worn brake pads | £30–£200+ |
| Battery charge light | Faulty alternator | £150–£400 |
| Airbag warning light | Clockspring, seat belt pretensioner | £100–£400 |
| Service warning light | Overdue service, minor fault | Variable |
Repair costs vary depending on your region, the garage you use, and the specific fault. It is recommended to obtain at least two quotes, and make sure that any parts sourced are compatible with your 308's engine and model year. AUTODOC stocks an extensive range of Peugeot 308 parts, from ABS sensors and brake pads to oil filters and AdBlue fluid. The platform has over 6.7 million spare parts from approximately 2,500+ brands available for delivery across the UK.
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Ignoring Peugeot warning lights rarely saves money. What begins as a warning about low brake fluid can, if left unattended, develop into a complete braking system failure. An engine management light that points to a blocked DPF, if dismissed, can eventually cause the DPF to crack – a repair that can exceed £1,000.
From an MOT perspective, millions of class 3 and 4 vehicles initially fail their MOT each year. Electrical equipment and lamps typically account for more than 10% of all major defect failures. An illuminated ABS warning light, a confirmed brake system fault, or a persistent engine management light will all cause a test failure. For the automatic gearbox, a warning light pointing to a gearbox fault may put the transmission into a protective limp mode, which limits the vehicle’s speed to protect components but makes the car undrivable in normal conditions. The cost of ignoring warning lights consistently exceeds the cost of addressing them promptly.
The Peugeot 308 warning lights system is one of the more informative on any family hatchback available in the UK. The colour-coded system makes it more straightforward to assess the urgency of issues, and the instrument panel messages add useful details, narrowing down the fault.
Some of the most frequently reported issues on UK 308 models include ABS wheel speed sensor faults (often linked to road salt corrosion), coolant temperature sensor failures, DPF-related engine management lights on diesel variants, and AdBlue system faults on BlueHDi engines. In most cases, a diagnosis with a diagnostic scanner will point directly to the cause and allow you to source the correct part, whether that is a replacement ABS sensor, a brake fluid top-up, or a new oil filter ahead of a service.
Staying on top of your dashboard warning lights keeps your 308 roadworthy, maintains its MOT eligibility, and, most importantly, keeps you and other road users safe.
A continuously flashing engine management light indicates a more serious fault than a steady light, typically a misfiring cylinder or a significant injection system issue. Reduce your speed, avoid hard acceleration, and get the vehicle checked as soon as possible. Continuing to drive with a flashing engine management light risks damaging the catalytic converter.
Yes. According to DVSA MOT regulations, an illuminated ABS warning light that indicates a confirmed system fault will result in an MOT failure. A faulty wheel speed sensor is the most common cause and is generally an affordable repair.
Locate the AdBlue filler cap: on most 308 models, it is next to the diesel filler cap behind the fuel flap, though on some early models it may be under the boot floor. Add AdBlue slowly using a suitable funnel or nozzle adaptor, adding at least 5 litres if the warning light is on. Do not overfill the tank or allow the AdBlue to contact painted surfaces (wash spills off with water). To reset the warning light, turn on the ignition without starting the engine, wait for 10 seconds for the system to register the new fluid level, and then start the car.
It depends on the cause. If the light is on because the parking brake is applied, simply release it. If it illuminates while driving with the parking brake released, check the brake fluid level immediately. A confirmed braking system fault means you should not drive the vehicle until it has been inspected. The braking system is too important to take chances with.
A single failing component, such as a wheel speed sensor or a fault in the BPGA fuse box on the battery, can trigger multiple warning lights simultaneously. The CAN network connecting the various electronic control units means that one faulty data signal can cascade across the ABS, ESP, parking brake, and other systems. An OBD diagnostic scan will retrieve individual fault codes, helping you to identify whether there is one root cause behind what appears to be several separate faults.
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