Fault code P1402 – a step-by-step guide to diagnosing and fixing it

Error code P1402 is displayed and the check engine light is on - what does this mean?

The DTC P1402 is a manufacturer-specific fault code that is recognized by the OBD-II/EOBD diagnostics and indicates a problem with the exhaust gas recirculation system (EGR). This trouble code occurs when the control unit detects a faulty function of the EGR flap or the associated sensor. For different manufacturers, this code can have different specific meanings, but usually refers to EGR system faults.

What causes can this error code have?

• Defective EGR flap
• Blocked EGR lines due to soot deposits
• Damaged EGR position sensor
• Defective vacuum lines to the EGR valve
• Faulty electrical connections on the EGR system
• Dirty or defective mass air flow sensor
• Leaking intake manifold gaskets
• Defective EGR control valve
• Blocked intake manifold

What symptoms occur in parallel with fault code P1402?

• Unsteady idling: The engine runs unstable or rough at idle
• Loss of power: Noticeable reduction in engine power, especially at low engine speeds
• Increased emissions: Deteriorated exhaust values and possible failure of the general inspection
• Knocking noises: Unusual noises from the engine compartment during operation
• Black smoke: Dark smoke coming from the exhaust
• Starting problems: Difficult to start, especially when the engine is cold

How can the problem with fault code P1402 be rectified?

• Repairing fault code P1402 requires a systematic approach to identifying and eliminating the cause.
• Remove the EGR flap, clean it thoroughly or replace it completely if it is very dirty
• Remove soot deposits from the EGR lines and ducts using a special cleaner
• Check EGR position sensor for correct function and replace if defective
• Check all vacuum lines to the EGR system for leaks and replace damaged hoses
• Check electrical plug connections on the EGR system for corrosion and clean or replace
• Clean the mass air flow sensor or replace with a new part if defective
• Check intake manifold gaskets for leaks and replace if necessary