EGR fault due to foreign bodies in the exhaust tract: causes and solutions

Information on diagnostics

Error messages such as P1444 and P16786 often indicate foreign bodies in the exhaust gas recirculation (EGR) system that interfere with engine operation. In particular, fragments from the catalytic converter or welding beads can block the EGR valve and result in a loss of power and increased nitrogen-oxide emissions. Thorough diagnostics and regular cleaning of the EGR system are essential to prevent damage and optimise engine performance. Our article sets out causes of and solutions to EGR errors.

Error messages such as P1444 and P16786 are often an indication of problems in the exhaust gas recirculation system (EGR) of a vehicle. These errors lead to symptoms such as engines running out-of-true, loss of power and jerking. Even if the air mass sensor is often suspected as the cause, in many cases foreign bodies from the exhaust tract are the real culprits that disrupt the operation of the exhaust-gas recirculation valve. The causes of these defects are varied, but fragments from the catalytic converter or welding beads in particular can cause problems.

Causes of EGR faults

In many cases, foreign bodies from around the catalytic converter enter the exhaust gas recirculation system due to pulsations in the exhaust tract or the vacuum in the intake air system. These foreign bodies block the exhaust-gas recirculation valve and prevent it from functioning properly. If the valve remains stuck open, exhaust gas is constantly recirculated, resulting in irregular combustion and increased nitrogen-oxide emissions. The symptoms are unstable engine running, loss of power and jerking, and fault codes such as P1444 (position sensor EGR valve — area / function error) and P16786 (EGR — throughput too large) may be stored in the fault code memory.

Damage and its consequences

A defect in the exhaust gas recirculation system can have serious consequences for the engine. If the EGR valve does not work properly due to a blocked component, this will increase fuel consumption and diminish engine performance. The catalytic converter and the turbocharger can also be impacted by constant malfunctions. Deposits in the combustion chamber and carbon deposits on components can occur, which can lead to further damage. Diesel engines are particularly affected by these problems, as the combustion temperature and nitrogen-oxide emissions are higher here. As a result, the cost of repairs increases as the affected gaskets and replacement components—such as the exhaust-gas recirculation valve and the catalytic converter—have to be replaced.

Causes of faults and diagnostics

Possible cause of damage: Broken pieces of the catalytic converter | Pierburg | Motorservice — Possible cause of damage: Broken pieces of the catalytic converter

The most common causes of these defects are soiling caused by soot or coking on the exhaust-gas recirculation valves. Foreign bodies in the exhaust tract can enter the system due to pulsations in the exhaust tract or the vacuum in the intake manifold and block the EGR valve, so accurate diagnostics performed by a repair shop is essential. An endoscope or visual inspection can be used to determine whether parts of the catalytic converter or other components are damaged. In many cases, it is necessary to replace the EGR valve and the catalytic converter to restore full engine performance and remove soiling.

Prevention and cleaning

To prevent these problems, it is advisable to clean the EGR system and the catalytic converter regularly. Diesel vehicles particularly benefit from regular maintenance of the exhaust gas recirculation system, as the exhaust gas recirculation can be particularly soiled here. Timely maintenance in a repair shop and replacing damaged components such as the exhaust-gas recirculation valve can help avoid the need for early repairs and the high costs associated with them.

Summary

A defect in the exhaust gas recirculation system due to foreign bodies can have far-reaching consequences for the engine: from increased fuel consumption to serious damage on important components such as the turbocharger and the catalytic converter. Thorough diagnostics in the repair shop is essential for reading out the fault code memory and rectify the fault. Regular maintenance, including the inspection and cleaning of gaskets and deposits, helps to minimise nitrogen-oxide emissions and maintain engine performance.