P1435 Fault Code

Long Description

For both Audi and Volkswagen, fault code P1435 is logged when the powertrain control module (PCM) has detected an issue with the secondary air injection system pump.

This happens when an electrical fault has been detected within the pump relay.

The secondary air injection system (SAIS) is used to pump ambient air into the vehicle’s exhaust system. This reduces the amount of unburned fuel that leaves the vehicle, particularly during cold start scenarios.

These systems were introduced in the 1960s to reduce emissions as catalytic converters only reach operational temperatures after running the engine for some time.

The SAIS is typically only found in petrol engines.

The generic fault codes that are similar to this issue include P0410 to P0419. Because this fault code indicates there is likely a short in the circuit, P0410 is the most similar in terms of a generic fault code.

Other Signs of This Problem

Issues with the SAIS can be hard to pick up on because of their relatively unique function. If the fault code is logged while the vehicle is running, it is possible that there will be no changes in driveability at all.

One of the most obvious signs of the problem is the presence of the Check Engine light on the dashboard.

Another instance in which issues with the SAIS can be detected is when starting the vehicle, particularly in cold climates.

The vehicle will likely idle rough until the catalytic converter has reached operating temperature. In some instances, black smoke will be emitted from the exhaust pipes.

What Could Be The Problem?

Because the fault code indicates that there is likely a short in the SAIS pump relay circuit, the causes for this issue will typically be electrical in nature. This can also include faulty components that short out the circuit.
A faulty air pump can cause the circuit to short.

Additionally, any electrical issues can be the cause. These typically include loose connections or damaged wires in the wiring harness. A blown fuse on the air pump can also cause this fault code.

A defective air bypass solenoid can also cause the system to malfunction.

A blockage in the SAIS can also lead to this fault code. This will typically be a result of carbon buildup.

Fixes

The fixes for this issue will involve finding the cause of the short circuit and repairing it. This can be both electrical or mechanical in nature.

The air pump circuit should be thoroughly checked. Any damaged wires or loose connections need to be replaced. If the fuse is blown, it needs to be replaced.

A faulty air pump must be fixed.

Any blockages in the SAIS need to be removed.

Any other mechanical faults in the SAIS must be fixed to help solve this code.

Seriousness

Fault code P1435 and other SAIS-related fault codes should be considered moderately serious. It can seriously decrease the driveability of the vehicle when starting it, particularly in cold weather.

It is a good idea to have this fault code fixed as soon as possible. If it occurs during winter, it is best to have this issue fixed immediately.