Fault code P1130 – a step-by-step guide to diagnosing and fixing it

Error code P1130 is displayed and the check engine light is on - what does this mean?

The DTC P1130 is a manufacturer-specific trouble code that mainly occurs in Toyota and Lexus vehicles and indicates a problem with the air-fuel mixture sensor (A/F sensor) in bank 1. The OBD system detects that the sensor is not responding properly to changes in the air/fuel ratio or is providing an inadequate signal. For other manufacturers, this code may indicate similar problems with lambda sensors or mixture control.

What can cause this error code?

• Defective air/fuel mixture sensor (A/F sensor)
• Damaged or corroded cable connections to the A/F sensor
• Loose or defective plug connections on the sensor
• Defective engine control unit (ECU)
• Vacuum leaks in the intake system
• Clogged or defective air filter
• Problems with the fuel supply or fuel pressure
• Defective ignition coils or spark plugs
• Exhaust leaks upstream of the A/F sensor

What symptoms occur in parallel with fault code P1130?

• Poor engine performance: The engine runs unevenly or has less power
• Increased fuel consumption: The vehicle consumes more fuel than usual
• Irregular idling: The engine runs rough or stutters when idling
• Starting problems: The vehicle is harder to start, especially when the engine is cold
• Black smoke from the exhaust: Indicates that the air/fuel mixture is too rich
• Jerking when accelerating: The engine reacts delayed or unevenly to accelerating

How can you fix the problem with fault code P1130?

• Repairing fault code P1130 requires a systematic approach to identify the exact cause.
• Replace the A/F sensor: Replace the faulty air-fuel mixture sensor in bank 1, as this is the most common cause of this EOBD code
• Check and repair cable connections: Inspect all wires and connectors to the A/F sensor for damage, corrosion or loose connections and repair or replace as needed
• Repair vacuum leaks: Locate and repair any leaks in the intake system, including hoses, gaskets and intake manifold
• Replace air filter: Replace a clogged or dirty air filter to ensure proper airflow
• Check fuel system: Test fuel pressure, fuel pump and injectors and replace defective components
• Maintain ignition system: Replace worn spark plugs and defective ignition coils to ensure complete combustion
• Inspect exhaust system: Look for leaks in the exhaust system upstream of the A/F sensor and repair them