Peugeot 308 P1435: what the additive pump fault means on a family diesel

Which 308s have an additive system

The T7 308 (2007 to 2013) with the 1.6 HDi or 2.0 HDi may have Eolys, depending on the engine and year. The T9 308 (2013 to 2021) with 1.6 or 2.0 BlueHDi commonly has Eolys feeding the particulate filter.

Later cars with the 1.5 BlueHDi generally do not have an additive tank. If one stores P1435, we check the VIN and software before accepting the code.

Euro 6 308s may also have AdBlue as a separate system with separate codes. The same system appears across the group. The 3008 and 5008 share it, as does the Citroën C4, so advice here often applies to them.

Where it sits on a 308 and why it fails

On the 308 the additive tank and pump sit beside the fuel tank under the rear of the car.

• Low and exposed

  A hatchback sits close to the road. The connector takes spray from the rear wheels, and winter salt works into the pins over a couple of seasons.

• Short family trips

  School runs and commuting rarely let the filter get hot. The system depends on the additive to regenerate at lower temperatures, so a pump that stops dosing quickly shows up.

• Garage visits and underbody work

  Exhaust, fuel tank and suspension jobs all happen near the pump. A plug left loose, or a loom trapped, is a repeat cause on cars that have had recent work.

• Towbars and bike racks

  A towbar fitting sits right beside the tank area on a 308 estate (SW), and the loom can be pulled or pinched.

What a 308 driver notices

A 308 is a light car, so limp mode feels like a car with a handbrake half on. The engine lamp comes on, and the dash may show an anti-pollution fault. Fuel use creeps up as failed regenerations waste fuel.

Because the 308 is a family car, drivers often carry on until it gets worse. That is when the filter fills and the repair bill grows. Booking early is cheaper.

Some drivers see "Risk of particle filter blocking". That message means dosing or regeneration has failed for some time. It is a prompt to act, not to wait.

What makes a 308 different to diagnose

The 308 has more electronic modules than a van, and network faults from other modules can mimic an additive problem. We scan everything and compare timing, not just engine codes.

We also see cars where a previous workshop swapped the pump but did not code it or reset the additive counter. The code then keeps returning. Reading the history tells us whether this is the case.

308 Eolys additive versus AdBlue

The two systems on a diesel 308 do different jobs. Eolys is mixed into the diesel to help the filter burn soot. AdBlue is injected into the exhaust on Euro 6 cars to reduce NOx.

P1435 sits on the Eolys side. If your 308 also shows an AdBlue warning, that is a separate fault and a separate repair. We can check both in one visit.

How we diagnose P1435 on a 308

We come to you, at home or work, and test with manufacturer-level equipment.

• Identify the system by VIN

  We confirm whether your 308 is T7 or T9, the engine, and whether it uses Eolys.

• Scan all modules

  We read every network module for lost-communication codes.

• Additive and soot live data

  Counters, refuel detection and filter pressure show if the pump has been dosing.

• Pump actuator test

  We command the pump from the tool to see if it responds.

• Measurements at the connector

  Supply, earth and CAN voltage and resistance, taken at the plug.

• Underbody check

  We inspect for corrosion, damage after recent work, and the condition of the tank unit.

308 P1435 repair and cost

We diagnose first, then agree a fixed price before work starts. No fix, no fee on the agreed outcome.

We are mobile and come to your drive, car park or workplace from 6am to 9pm, 7 days a week, including bank holidays. Most 308 repairs are completed in one visit. If a part is needed, we confirm it, quote it fixed, and return to fit and code it with a written warranty.

• Connector and loom repair

  Clean or replace corroded pins, repair damaged wires and secure the loom.

• Pump or tank replacement

  Only after the wiring has been proven good. Coded and tested after fitting.

• Refill and reset

  The right Eolys for your tank type, and the additive counter reset.

• Regeneration and test drive

  A service regeneration if soot has built up, and a road test.

• Mobile diagnosis and simple fix: From £249 Callout, diagnosis and fixes like a connector or wiring repair.
• Additive pump or tank assembly: Fixed price after diagnosis Quoted once the cause is proven.
• Service regeneration: Quoted on the day Depends on the soot mass found.

P1435 questions

Does my 308 1.6 BlueHDi have an additive tank?

The T9 308 with 1.6 BlueHDi commonly does. We confirm by VIN, because fitment varies by year and variant.

Does the 3008 or 5008 use the same system as the 308?

Many do, on the same engines and years. The layout can differ, so we confirm by VIN. The Citroën C4 also shares the system.

My 308 estate had a towbar fitted and now shows P1435. Is it linked?

Very possibly. The pump loom runs close to the tank area. We check for trapped, pulled or unclipped wiring.

Is it safe to drive my 308 with this code?

Usually for short, careful trips. Without additive the filter loads faster, and a blocked filter means limp mode and a larger bill.

Will my 308 pass an MOT with P1435 stored?

A lit engine warning can lead to a failure, and a blocked filter affects emissions. It is best to have the fault repaired first.

Why did a garage replace the pump and the code came back?

Often the wiring or connector was the real fault, or the new pump was not coded and the counter not reset. We prove the circuit first.