P1435 on a Peugeot: 308, 3008, 5008, 508, Partner, Expert and Boxer

Peugeot, the FAP and why it needs additive

Peugeot was the first car maker to put an additive-assisted diesel particulate filter into production, on the 607 in 2000. It calls the filter the FAP, short for filtre à particules, and that term still appears in handbooks and on the dash. A cerium-based additive, sold as Eolys, is metered into the fuel tank by a small pump at each refuel. It makes soot in the filter burn at about 450°C rather than about 600°C, which suits real-world driving.

When the additive supply stops, the filter loses its safety margin. Regenerations need more heat than a typical commute provides, so they are interrupted or never started. Soot builds up, back-pressure rises and the ECU eventually limits power. P1435 is often the first sign that dosing has a problem, and it can sit stored well before the filter becomes a concern.

Peugeot moved to a flexible pouch tank and a multiplexed pump on later cars, from around 2010. The pump now has its own electronics and sends messages to the engine ECU over CAN. P1435 is the ECU saying that conversation has failed or the pump has flagged a fault.

Peugeot models where we see P1435

This list shows where the additive system is most often fitted. A VIN check always comes before work, because engine and year change the answer.

• 308 (T7 and T9)

  The 1.6 HDi and 1.6 BlueHDi engines are the ones to watch. Wiring faults under the rear of the car are usual, and the car often sets P1434 as well.

• 3008 and 5008

  The first-generation 2.0 HDi and 1.6 HDi and, later, BlueHDi versions. Both are family cars used for short trips, which makes a filter lacking additive support clog fast.

• 508

  Mostly the 2.0 HDi and BlueHDi. High-mileage executive use means the pump and loom have often had years of salt exposure.

• Partner and Expert

  Van versions of the same engines, with heavy daily use. See our Partner and Berlingo page if the van also has an AdBlue system.

• Boxer

  Fitment depends on the engine and year, so a VIN check is essential. The wiring route is long on a Boxer and exposed to road damage. Our Boxer AdBlue page covers the SCR side.

• Rifter-era and newer vehicles

  Cars built on newer platforms with the 1.5 BlueHDi (DV5), from about 2018, generally do not use an additive tank. P1435 is therefore much less likely there, and we look at other causes.

Peugeot dash messages and what they mean

The wording changes by model, but the meaning does not.

• "Engine fault" or "Anti-pollution system faulty"

  A general message with the warning light. The code is stored but the car may drive normally for now.

• "Risk of particle filter blocking"

  The filter is loading. If dosing has failed, repeated drives will not clear it. The sooner the cause is repaired, the better the chance of avoiding a forced regeneration.

• "Particle filter additive level too low"

  A different fault: the additive is running out or the ECU thinks it is. This needs a refill and counter reset, and the pump circuit should also be tested.

• "Fault: power limited"

  The ECU is protecting the engine. We treat it as a priority, because a blocked filter is much more expensive than a wiring repair.

Common causes on Peugeots

On the 308 and 3008 the most common cause we find is a corroded additive pump connector, followed by chafed wiring near the tank straps. On vans, such as the Partner, Expert and Boxer, damage to the loom from kerbs, mud and previous repairs is more common. We have also found P1435 caused by a poorly refitted plug after exhaust or tank work.

A genuinely failed pump is possible, particularly on older cars and high-mileage vans. We check supply, earth and CAN at the plug first, and run a commanded pump test. Only then do we recommend a new pump or pouch tank assembly.

Peugeot Eolys and AdBlue are not the same thing

A Peugeot can have two completely separate fluid systems. The additive in the Eolys tank goes into the fuel to protect the FAP. AdBlue goes into a different filler and is injected into the exhaust to cut NOx. Many Euro 6 Peugeots from around 2014 carry both, so a fault on one side is easily mistaken for a fault on the other.

P1435 is an additive fault. AdBlue problems show as countdowns, SCR messages and codes such as P20EE or P20E8. If you are seeing both, the repairs are separate. We can diagnose both on the same visit and price them separately.

Our P1435 diagnosis on a Peugeot

Everything is done where the vehicle is parked. We measure first and replace later.

• Check the system fitted

  VIN and engine code tell us whether there is an Eolys tank, which generation it is and whether there is an AdBlue system too.

• Read every module

  A full-system scan shows whether the network code U0118 sits in another module, and which codes arrived first.

• Live additive data

  We look at the additive counter, refuel detection, pump status, soot mass and exhaust pressure difference. If the counter did not move at the last fill, dosing is not happening.

• Run the pump from the tool

  The actuator test tells us at once whether the pump responds, and so whether the wiring is the likelier culprit.

• Meter on the plug

  Supply and earth under load, then CAN high and low voltage and resistance, measured at the connector.

• Visual check of the underside

  We look at the plug, wires, pouch housing and hoses, and at any signs of previous work that may have disturbed them.

Fixing P1435 on a Peugeot

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

We come to your drive, yard, depot or roadside from 6am to 9pm, every day including bank holidays. Fleet operators can book Partners, Experts and Boxers together. Repairs carry a written warranty.

• Wiring and connector repair

  Corroded terminals replaced, cut or chafed wires repaired, and the loom re-routed to stop it happening again.

• Pump or pouch replacement

  Fitted only when the circuit is proved good. We prime it, code it and run a test before handing back.

• Additive refill and counter reset

  The correct Eolys fluid for your VIN goes in, and the additive counter is reset with diagnostic equipment.

• Regeneration and road test

  A service regeneration clears accumulated soot where needed, then we road test and recheck for codes.

• Mobile diagnosis and straightforward fix: From £249 Includes callout, live data and fixes such as a connector or wiring repair.
• Additive pump or pouch tank: Fixed price after diagnosis Only quoted once the electrical circuit is proved.
• Service regeneration: Quoted on the day Needed only if the filter has loaded up.

P1435 questions

Is P1435 common on the Peugeot 308?

It is one of the more frequent faults on 308 diesels with the additive system. The cause is usually the pump connector or wiring, though a failed pump is possible on higher-mileage cars.

What does FAP mean on my Peugeot dashboard?

FAP stands for filtre à particules, the French term for the diesel particulate filter. A FAP message relates to the filter, and may involve the additive system if it mentions additive or blocking.

Does the Peugeot 3008 use AdBlue or Eolys?

Some versions use Eolys, some use AdBlue and many Euro 6 versions use both. We confirm which by VIN before quoting.

My Peugeot Boxer has P1435. Is it the same fix?

The code means the same thing, but the wiring route and parts differ. We check the VIN, test the circuit and give a fixed price for your Boxer specifically.

Will an additive top-up cure a risk of particle filter blocking message?

Only if the cause is a low level. If the pump or its wiring is faulty, new fluid will not dose, and the message returns. We test before adding anything.

Does a Peugeot 1.5 BlueHDi get P1435?

Rarely. The 1.5 BlueHDi from about 2018 generally has no additive tank, so a P1435 on that engine would be unusual. We verify the system by VIN.