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Home / Codes / P1516
DTC code page

P1516: Throttle Actuator Control Module Throttle Actuator Position Performance

Quick answer: The controller sees the electronic throttle plate failing to follow commanded position the way it should.

Drivers also search this fault as throttle actuator control position performance, reduced engine power throttle code, P1516 throttle actuator performance.

Severity: high Family: powertrain Related paths: 10
Meaning

What P1516 usually means

P1516 is one of the signature reduced-engine-power codes because it usually shows up when the throttle body stops behaving like a trustworthy actuator. On many GM applications, the engine computer is comparing commanded throttle movement with what the throttle position sensors report back, and the story no longer matches closely enough to stay confident. That can happen because of carbon drag, a failing throttle body, wiring or connector trouble, voltage instability, or pedal and throttle signals that disagree badly enough to force a protection strategy.

Fast triage

Start here before chasing parts

  • Scan first: save freeze-frame and pending codes before clearing anything.
  • Confirm the complaint: compare the stored code with current drivability symptoms.
  • Use context: trims, live data, and related codes usually narrow the fault faster than guesswork.
  • Work simplest to hardest: leaks, connectors, maintenance items, and known patterns before expensive components.
Initial checks

What to check first

  • If the cluster says Reduced Engine Power, treat P1516 like a protection event, not a cosmetic sensor complaint.
  • Inspect battery voltage and charging health before condemning the throttle body, especially if multiple electronic codes are present.
  • Check for obvious throttle-body contamination or signs the plate is sticking near idle.
Driving risk

Can you keep driving?

A vehicle with active P1516 may idle and creep, but it can also drop into severe reduced-power mode unexpectedly. Diagnose it soon, especially if acceleration is already limited.

High urgency: If symptoms are active, reduce driving and diagnose quickly before secondary damage builds.
Symptoms

Common symptoms

  • Reduced Power
  • Rough Idle
  • reduced engine power message
  • poor throttle response or limp mode
  • car will not accelerate normally
  • idle changes after throttle body issue
Likely causes

Common causes behind this code

  • Throttle body motor or position sensor fault inside the electronic throttle assembly
  • Carbon buildup or binding that keeps the throttle plate from moving cleanly
  • Connector, harness, ground, or reference-voltage problem affecting throttle signals
  • Accelerator-pedal or throttle-position correlation issue forcing a protective strategy
  • Low system voltage or poor power feed making the throttle actuator look erratic

Cause phrases often tied to this code: dirty throttle body, bad throttle actuator, throttle position sensor mismatch, wiring issue, low voltage.

Diagnostic order

Suggested workflow

  1. Capture all throttle, pedal, and low-voltage companion codes before clearing anything.
  2. Inspect the throttle body and connector for contamination, water entry, bent pins, or harness strain.
  3. Compare commanded throttle position to actual throttle feedback if scan data is available.
  4. Verify battery, grounds, and reference-voltage stability because electronic throttle systems hate ugly voltage.
  5. If the signals and power supply are healthy but the actuator still cannot track command, move toward throttle-body replacement or OE-level setup procedure.
Avoid guesswork

Common mistakes

  • Cleaning the throttle body aggressively and assuming the code cannot return if the real problem is sensor or motor performance.
  • Replacing the accelerator pedal before proving the throttle body and wiring side of the story.
  • Ignoring low voltage or poor grounds even though reduced-power throttle faults are extremely voltage-sensitive.
Repair path

Practical fix guidance

  • Repair the verified throttle-body, wiring, connector, ground, or voltage problem behind the position-performance failure.
  • After repair, confirm idle quality and throttle response through multiple restarts and road-load checks.
  • If reduced-power mode was active, verify the vehicle exits it fully and does not return on the next drive cycle.
Vehicle context

Affected brands in this MVP

Brand hubs help broaden internal linking now and can evolve into make-specific diagnostic notes later.

Aliases and common searches

English phrases tied to P1516

Useful when the driver knows the wording but not the exact DTC yet.

  • throttle actuator control position performance
  • reduced engine power throttle code
  • P1516 throttle actuator performance
Related search intent

Queries this page can answer naturally

  • P1516 code meaning
  • what does P1516 mean
  • P1516 reduced engine power
  • throttle actuator control module throttle actuator position performance
FAQ

Quick questions about P1516

Does P1516 always mean I need a throttle body?

No. Dirty throttle plates, wiring issues, poor grounds, and low voltage can all create the same performance mismatch.

Why does P1516 often come with Reduced Engine Power?

Because the ECU limits throttle authority when it cannot trust where the throttle plate really is.

Can a weak battery trigger P1516?

Yes. Electronic throttle systems can become erratic when system voltage or grounds are unstable.