Fault code P1435 – a step-by-step guide to diagnosing and fixing it

Error code P1435 is displayed and the check engine light is on - what does this mean?

The DTC P1435 is recognized by the OBD/EOBD system when a problem is detected with the secondary air system or the air pump. This manufacturer-specific fault code mainly affects the secondary air system, which is used to reduce emissions during the engine warm-up phase.

What can cause this fault code?

• Defective secondary air pump
• Blocked or damaged air lines
• Defective secondary air switching valve
• Damaged plug connections on the air system
• Defective vacuum lines
• Clogged air filter of the secondary air pump
• Faulty relays in the secondary air system
• Defective non-return valves
• Corrosion or wear on system components

What symptoms occur in parallel with fault code P1435?

• Increased emission values: The vehicle produces more pollutants than permitted
• Starting problems when the engine is cold: Extended warm-up phase or irregular engine running
• Irregular idling: Engine runs unevenly, especially during the warm-up phase
• Reduced engine power: Noticeable loss of power during the first few minutes of driving
• Noticeable engine noises: Unusual noises from the secondary air system
• Failed emissions test: Problems with the TÜV emissions test

How can the problem with error code P1435 be resolved?

• Fixing trouble code P1435 requires a systematic diagnosis of the secondary air system.
• Replace the secondary air pump: Remove defective pump and replace with new original parts, including seals and fastening material
• Clean or replace air lines: Flush out clogged lines or replace completely if damaged
• Replace the switching valve of the secondary air system: Remove defective valve and install new valve with correct specifications
• Repair electrical connections: Clean, seal and firmly connect corroded or loose plug connections
• Replace vacuum lines: Replace cracked or porous vacuum hoses with new lines
• Change secondary air pump air filter: Remove clogged filter and insert new filter according to manufacturer's specifications
• Check relays and fuses: Replace defective relays and check fuses for correct amperage values