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P1565

Idle Speed Control Throttle Position Lower Limit Not Obtained.

  • Volkswagen
  • Powertrain
  • Manufacturer code
  • Medium severity

How this code is built

P
SystemPowertrain
1
Defined byThe manufacturer
5
AreaVehicle speed, idle control and auxiliary inputs
65
FaultThe specific fault in that area

What it means

On Volkswagen, P1565 means the engine control unit could not reach the lower limit of throttle position during idle speed control or throttle adaptation. The throttle valve did not return to, or learn, its expected closed (idle) position. This is usually down to a dirty or sticking throttle body, an air leak, or a throttle body adaptation that has been lost or has failed.

Symptoms

  • Engine management light on
  • Unstable, hunting or too high or low idle speed
  • Engine stalling or nearly stalling when stopping or coming to rest
  • Hesitation or poor response off idle
  • Hard starting or rough running when cold
  • Possible limp-home mode with reduced throttle response on some models

Possible causes

  • Carbon and dirt build-up in the throttle body restricting or sticking the throttle plate near closedlikely
  • Throttle body adaptation (basic setting) lost after battery disconnection, throttle cleaning or ECU change, or not completed correctlylikely
  • Unmetered air leak such as a split intake hose, loose clamp, leaking intake manifold gasket or perished vacuum hoselikely
  • Faulty throttle body or throttle position sensor, or worn throttle drive, so the closed position is not read correctlypossible
  • Wiring or connector fault in the throttle body circuit (poor contact, corrosion, high resistance, damaged wires)possible
  • Low or unstable battery or supply voltage upsetting the throttle adaptationpossible
  • Fault in the engine control unit itselfrare

How to diagnose

  1. Read all stored fault codes and freeze frame data, and note whether other throttle, idle or mixture codes are present
  2. Check the battery condition and charging voltage, as low voltage can stop adaptation completing
  3. Visually inspect the intake pipework, clamps, breather and vacuum hoses and the manifold area for splits, loose fittings or leaks
  4. Inspect the throttle body connector and wiring for damage, corrosion, loose pins or chafing
  5. Remove the intake pipe and check the throttle plate and bore for carbon build-up or sticking, and that it moves freely
  6. Using a diagnostic scan tool, view live data for throttle angle and idle values, and check the closed position and any adaptation status against the model's specification
  7. Run the throttle body basic setting or adaptation procedure for that model and engine, following the manufacturer's procedure, and see if it completes
  8. Check for air leaks with a smoke test if the idle remains unstable and adaptation fails

How to fix

  • Clean the throttle body using a suitable cleaner as per the manufacturer's guidance, taking care not to force the throttle plate on electronic throttles, then carry out the throttle adaptation
  • Repair or replace leaking intake hoses, seals, gaskets or vacuum lines
  • Repair damaged wiring or connectors in the throttle body circuit
  • Replace the throttle body if it is faulty, worn or will not adapt, and then complete the adaptation procedure
  • Restore battery and charging system health, then repeat the adaptation and clear the code
  • Have the control unit checked and, if it is found faulty, repaired or replaced as per the manufacturer's procedure

Can I keep driving?

Medium severity

The car can usually be driven for a short time, but poor idle and a risk of stalling make it unsafe in traffic, so get it fixed soon. If it enters limp-home mode or stalls repeatedly, limit driving until it is repaired.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.

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