Fault code P1156 – a step-by-step guide to diagnosing and fixing it

Error code P1156 is displayed and the check engine light is on - what does this mean?

The DTC P1156 is a manufacturer-specific fault code that is recognized by the OBD system and indicates a problem with the air supply or the air-fuel mixture. This trouble code mainly occurs in Honda and Acura vehicles and refers to a malfunction in the area of the oxygen sensors or the fuel supply.

What can cause this error code?

• Defective oxygen sensor (O2 sensor)
• Clogged or defective fuel injectors
• Leaking vacuum lines
• Damaged mass air flow sensor
• Defective fuel pump
• Clogged air filter
• Faulty spark plugs or ignition coils
• Loose or corroded plug connections
• Defective fuel pressure regulator valve
• Dirty throttle valve

What symptoms occur in parallel with fault code P1156?

• Loss of engine power: The engine runs unevenly and loses power
• Increased fuel consumption: The vehicle consumes more fuel than usual
• Starting problems: The vehicle is difficult to start or will not start
• Irregular idling: The engine runs unstable or stalls when idling
• Black smoke from the exhaust: Indicates that the fuel/air mixture is too rich
• Jerking when accelerating: The vehicle jerks or stutters when accelerating

How can the problem with error code P1156 be rectified?

• Repairing EOBD fault code P1156 requires a systematic approach to identify the exact cause.
• Check oxygen sensors and replace if necessary, as defective O2 sensors are often the cause of this fault code
• Clean or replace fuel injectors if they are clogged or defective
• Check all vacuum lines for leaks and replace damaged hoses
• Clean or replace the mass air flow sensor if it is dirty or defective
• Check fuel pump and fuel filter and replace if necessary
• Check air filter and replace if dirty
• Check spark plugs and ignition coils for proper function and replace defective parts
• Check all electrical connections for tightness and corrosion and clean them