Peugeot 408 DASHBOARD WARNING LIGHTS
Every symbol. Every symptom. Every cost. From the 1.2 PureTech to the Hybrid 225 – we cover 15+ essential dashboard warnings with step‑by‑step diagnosis, multiple repair paths, and real‑world garage prices. Whether it’s a red oil can or an amber AdBlue light, you’ll know exactly what to do.
Pro tip: bookmark this page – we update costs quarterly.
Engine check / MIL amber/red
⚙️ Issue: ECU detects misfire, lambda sensor, turbo, or EVAP fault. On 1.2 PureTech, timing belt degradation may trigger.
- Symptoms: loss of power, rough idle, increased consumption, flashing = catalyst damaging misfire.
- Diagnosis: 1️⃣ OBD2 scan (generic codes). 2️⃣ Check fuel cap. 3️⃣ Live data fuel trims, O2 sensors. 4️⃣ Compression test / borescope for 1.2 PureTech timing belt.
Oil pressure red
⚙️ Issue: Low oil level, worn pump, clogged strainer, or faulty pressure switch. On 1.5 BlueHDi, chain tensioner issues.
- Engine ticking, warning flickers in corners, possible knocking.
- 1️⃣ Stop immediately, check dipstick. 2️⃣ Manual pressure test with gauge. 3️⃣ Remove oil pan inspect pickup. 4️⃣ Check oil filter anti‑drain valve.
Battery charge red
⚙️ Issue: Alternator failure, broken belt, or defective AGM battery (stop‑start).
- Dim headlights, slow crank, “economy mode active” on screen.
- 1️⃣ Multimeter (12.5V off, 13.8‑14.8V running). 2️⃣ Load tester for battery. 3️⃣ Check alternator exciter signal (LIN bus).
Brake warning red
⚙️ Issue: Low fluid, worn pads (sensor), handbrake switch, or ABS pump failure.
- Spongy pedal, squeal, longer travel.
- 1️⃣ Check fluid level (and leak). 2️⃣ Inspect pad thickness & wear sensor wires. 3️⃣ Scan ABS module for fault codes.
ABS / ESP amber
⚙️ Issue: Wheel speed sensor, steering angle sensor, or yaw rate sensor.
- ABS inactive, ESP OFF, traction control warning.
- 1️⃣ Read codes (C10**, C13**). 2️⃣ Inspect sensor wiring & tone ring. 3️⃣ Live data wheel speeds. 4️⃣ Steering angle reset with scan tool.
Tyre pressure (TPMS) amber
⚙️ Issue: Underinflation, sensor battery dead, or faulty receiver. 408 uses direct TPMS (Schrader).
- Symbol + “tyre underinflation” message, sometimes pressure displayed.
- 1️⃣ Check pressure manually. 2️⃣ TPMS trigger tool to wake sensors. 3️⃣ Relearn procedure via infotainment. 4️⃣ Diagnose with diagbox for sensor IDs.
Airbag (SRS) red
⚙️ Issue: Occupant classification sensor (passenger seat), clock spring, or crash sensor.
- Light stays on, passenger airbag off may flash.
- 1️⃣ SRS scan (B1000, B1340). 2️⃣ Check under‑seat connectors (yellow). 3️⃣ Multimeter on clock spring. 4️⃣ Seat mat sensor replacement if needed.
Coolant overheat red
⚙️ Issue: Low coolant, stuck thermostat, electric fan failure, or head gasket.
- Needle in red, steam, coolant smell, loss of power.
- 1️⃣ Stop engine, check expansion tank. 2️⃣ Pressure test system. 3️⃣ Check fan operation (A/C on). 4️⃣ thermostat removal/test.
AdBlue / urea amber/red
⚙️ Issue: Low level, poor quality, crystallised injector, or NOx sensor fault. BlueHDi models.
- “AdBlue low” countdown, after 2400km no restart, engine warning.
- 1️⃣ Refill with certified fluid. 2️⃣ Check AdBlue heater/level sensor via diag. 3️⃣ Inspect injector for crystallization. 4️⃣ NOx sensor readings.
DPF / FAP amber
⚙️ Issue: Filter clogged, additive low (Eolys), or pressure sensor fault. BlueHDi 1.5/2.0.
- Loss of power, regeneration too frequent, “particle filter clogged” message.
- 1️⃣ Check ash load with diag. 2️⃣ Forced regen via scan tool. 3️⃣ Check additive level (Eolys). 4️⃣ Differential pressure sensor tubing.
Power steering red/amber
⚙️ Issue: Electric power steering (EPS) motor, torque sensor, or network fault. Common on 408.
- Heavy steering, warning light, intermittent assist.
- 1️⃣ Read steering angle & torque sensor values. 2️⃣ Check battery voltage (low volts = no assist). 3️⃣ EPS calibration with Diagbox.
Lane departure / Active safety amber/green
⚙️ Issue: Front camera blocked (dirt/ice), calibration needed, or sensor failure.
- “Lane keeping assist unavailable”, warning on dash, function inactive.
- 1️⃣ Clean windscreen area around camera. 2️⃣ Check for fault codes (C1Axx). 3️⃣ Camera recalibration with special target.
Collision alert / AEB amber
⚙️ Issue: Radar misalignment, blocked sensor, or faulty radar unit.
- “Active safety brake limited” or “sensor blinded” warning.
- 1️⃣ Check front Peugeot emblem (radar) for dirt/damage. 2️⃣ Radar alignment with diagnostic tool. 3️⃣ Measure radar voltage supply.
Stop‑start (eco) green/amber
⚙️ Issue: Battery state of charge low, outside temp, or faulty voltage sensor.
- “Stop‑start unavailable” on cluster, system inactive.
- 1️⃣ Check AGM battery health (SOC >75%). 2️⃣ Read battery status via diag. 3️⃣ Check brake vacuum sensor. 4️⃣ Reset BSI after battery replacement.
Service (spanner) amber
⚙️ Issue: Oil change interval reached, brake wear, or other scheduled maintenance.
- Spanner light + “service due” message.
- 1️⃣ Check service history / interval. 2️⃣ Use menu to reset (if after service). 3️⃣ If persistent, check for pending faults.
detailed price matrix (parts + labour)
| Warning / system | Common repair | Cost range (€) |
|---|---|---|
| Engine MIL | O2 sensor / coil pack | 150 – 600 |
| Oil pressure | Pressure switch / pump | 180 – 1400 |
| Battery charge | Alternator / battery | 120 – 750 |
| Brake pad wear | Pads + sensor | 150 – 350 |
| AdBlue | Refill / injector | 15 – 900 |
| DPF | Forced regen / cleaning | 180 – 600 |
| Power steering | Torque sensor / column | 300 – 1400 |
| Lane departure | Camera calibration | 200 – 850 |
prices include diagnosis & VAT (EU average).
