Engine

P1516 — Throttle Actuator Control Module Performance Fault

Severity: medium Drive with care, to a shop

What P1516 means

The ECU compares the commanded electronic throttle position with the actual position reported by the position sensors. If the plate does not reach the target angle or drifts from it, P1516 is stored. The exact definition varies by manufacturer: on GM and several others it points to the throttle actuator, while some brands use it for the intake manifold runner control system.

Symptoms

  • Reduced engine power message
  • Limp mode
  • Unstable or hunting idle
  • Sluggish throttle response
  • Check engine light on
  • Stalling at idle

Possible causes

  1. Dirty throttle body
  2. Failing throttle actuator motor
  3. Throttle relearn not done after battery disconnect
  4. Damaged wiring or poor connection at the throttle body
  5. Faulty throttle or pedal position sensors
  6. Low system voltage from a weak battery or bad ground
  7. ECU fault (rare)

How to diagnose

  1. Scan all codes and freeze-frame data, looking for related throttle or pedal codes
  2. Inspect the throttle connector and harness for corrosion and damage
  3. Test battery voltage and check terminals and grounds
  4. Remove the intake duct and check the plate for carbon buildup or sticking
  5. With the key off, move the plate by hand to confirm it moves freely and springs back
  6. Compare commanded and actual throttle position and sensor readings on a scan tool
  7. Test power, ground and signal circuits at the throttle with a multimeter
  8. Perform the throttle relearn after cleaning or replacement

Common fixes

  • Clean the throttle body and run a throttle relearn
  • Replace the throttle body assembly if the motor or sensors are bad
  • Repair the wiring or connector
  • Replace the battery or restore a good ground
  • Perform the throttle relearn with a scan tool

P1516 on different brands

Chrysler
Throttle Actuator Control (TAC) module throttle actuator position performance: the module finds the actuator position implausible for current conditions.
Ford · manuals
Intake manifold runner control input error, bank 1.
Honda · manuals
Throttle position motor position performance fault.
Land Rover
Fault in the intake manifold air control system.
Porsche
Fault in the intake manifold resonance flap.
Subaru · manuals
Idle air control (IAC) valve circuit 4 voltage low.
Suzuki · manuals
Throttle actuator control module throttle actuator position performance fault.
VAG
Open circuit in intake manifold air control solenoid 1.

Questions and answers

Can I drive with a P1516 code?

Only briefly and carefully, for example to a shop. Power is usually limited and throttle response can be unpredictable, so do not put off diagnosis.

Will cleaning the throttle body fix P1516?

Often, if carbon buildup is the cause. Run a throttle relearn afterward, or the idle may stay rough.

Why did P1516 appear after disconnecting the battery?

Losing power can erase the learned throttle positions in the ECU. A throttle relearn with a scan tool or the manufacturer's procedure usually clears it.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.