Throttle Actuator A Control System - Idle Position Not Learned

What it means

The engine computer needs to learn the throttle position that gives a correct idle speed. It has found that it could not complete this learning, which usually happens after the throttle body is cleaned or replaced or the battery is disconnected without doing the relearn procedure.

Related codes: P2119P2101P0505P0506P0507

Symptoms4

• High, low or unstable idle.
• Stalling at a stop or when the A/C turns on.
• Check engine light on.
• Occasional hard starting.

Possible causes5

• Throttle relearn not done after cleaning or replacing the throttle body or disconnecting the battery.
• Carbon-fouled throttle body preventing the computer from reaching the correct position.
• Air leak from vacuum hoses or the intake manifold gasket.
• Low battery voltage during the learning attempt.
• Failed throttle body or its built-in sensor.

How to diagnose5

1. Ask about any recent work on the throttle body or battery, since it is the most common cause.
2. Inspect the throttle body for carbon.
3. Check vacuum hoses and the intake manifold for air leaks, or have a smoke test done.
4. Check that battery voltage is adequate before starting the relearn.
5. Run the relearn with a scan tool and see whether it completes successfully.

How to fix5

1. Perform the idle position relearn with a scan tool or per the manufacturer method.
2. Clean the throttle body, then repeat the relearn.
3. Repair any air leak before relearning.
4. Replace the throttle body if the relearn fails with everything else in good order.
5. Clear the codes and confirm a stable idle and that the code does not return.

A relearn or cleaning is usually enough at low cost; the cost rises only when a new throttle body is needed.

Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026

Frequently asked questions