Fault code P1505 – a step-by-step guide to diagnosing and fixing it

Error code P1505 is displayed and the check engine light is on - what does this mean?

The DTC P1505 is recognized by the OBD system if there is a problem with the idle control valve or the idle control. This manufacturer-specific fault code mainly affects the air management system and can have different meanings for different vehicle makes, but usually refers to faults in the idling range.

What causes can this fault code have?

• Defective idle control valve (IAC valve)
• Dirty or blocked mass air flow sensor
• Leaking intake lines or torn hoses
• Faulty throttle valve or throttle valve sensor
• Defective vacuum lines
• Damaged cable connections to the idle control valve
• Clogged air filter
• Faulty engine control unit (ECU)
• Loose or corroded plug connections

What symptoms occur in parallel with fault code P1505?

• Irregular idling: The engine runs unevenly or fluctuates when idling
• Engine stalling: The vehicle stalls when idling or when stopping
• High idling: The idling speed is significantly increased
• Starting problems: Difficulty starting, especially when the engine is cold
• Jerking when accelerating: Uneven engine performance at low engine speeds
• Increased fuel consumption: Poorer fuel efficiency due to impaired air control

How to fix the problem of error code P1505?

• Repairing the P1505 trouble code requires a systematic diagnosis of the idle control.
• Remove the idle control valve, clean thoroughly or replace completely if defective
• Clean the mass air flow sensor with a special cleaner or replace if damaged
• Check all intake lines and vacuum hoses for cracks or leaks and replace defective parts
• Dismantle and clean the throttle valve and test the throttle valve sensor for correct function
• Check the air filter and replace if dirty or blocked
• Check electrical connections to the idle control valve, clean plug connections and repair damaged cables
• Delete fault memory after repair and carry out test drive