1. Home
  2. /
  3. Complete List of OBD2...
  4. /
  5. P1516 Code – What...

P1516 Code – What Does It Mean & How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.


P1516 is an OBD-II Code that refers to Throttle Actuator Control Module Throttle Actuator Position Performance


A P1516 code is a manufacturer specific trouble code, that may only occur in vehicle makes, such as GM (Chevrolet/GMC), Saturn, etc. The PCM (powertrain control module, or ECM or engine control module) serves as the command center for the TAC (Throttle Actuator Control) system and determines the appropriate response on the throttle of the driver. Each control unit monitors the data and compares it to the target throttle position. P1516 is a fault code that appears when the PCM finds an out-of-range issue between the predicted and actual throttle position.


Common causes for this code include:

  • Faulty TAC module
  • Water in TAC module connector
  • The throttle body is either binding or bent.
  • Open or shorted TAC module harness
  • TAC module circuit has a faulty electrical circuit


The symptoms of a P1516 code are:

  • No throttle response
  • Check Engine light ON


To diagnose a P1516 DTC code, a technician would:

  1. Scan for codes in the ECM and look at the freeze frame data for failure.
  2. The vehicle may be in safe mode and unable to be driven until the condition has been corrected.
  3. Check for Throttle Position Sensor (TPS) electrical and mechanical anomalies.
  4. Look for water in the connector and other wiring harness problems.
  5. Verify shorted or open circuits, look at component specification lists to verify specifications.
  6. Verify the correct operation of the PCM using a scan tool.

Common mistakes

The following are some of the most common mistakes that a technician may make when diagnosing a P1516 code:

  • Not properly identifying the cause of the problem when using Freeze Frame Data for P1516 and TPS voltage checks.
  • Verifying that all wiring and connectors are in good condition without proper tools or testing methods.
  • Not following proper diagnostic procedures to include testing components before replacing them to avoid unnecessary replacement.
  • Not keeping the engine running when idle for a certain period of time, which can lead to other faults not being diagnosed correctly.
  • Assuming that the Throttle Position Sensor (TPS) is not working properly if it does not show any voltage at all times, even though the PCM is commanding a certain voltage.

How serious is this?

A P1516 code is not considered to be an extremely serious issue, but it would be on the higher end on the seriousness scale. Failure to take action with this code could lead to a loss of acceleration and possible stalling. This trouble code is also considered as a technical violation if the vehicle is being driven but does not have sufficient power for safe driving conditions.

What repairs can fix the code?

The following are solutions that may fix this problem:

  • Cleaning the throttle body before replacing anything may fix the issue
  • Replacement of TAC module
  • Replace the TAC module harness if it is damaged or fails
  • Removing water in TAC module connector
  • Fix poor electrical connection in the TAC module circuit
  • Replace damaged throttle body or binding as needed

Related codes

A P1516 is related to and may be accompanied by the following codes:

P0113 – Throttle Position Sensor A Signal High Input

P0335 – Ignition Coil Primary/Secondary Circuit Malfunction

P0420 – Catalytic Converter System Efficiency Below Threshold (Bank 1)

P1517 – Throttle Actuator Control Motor Circuit Low Voltage


In conclusion, the P1516 code is a diagnostic trouble code that refers to the Throttle Actuator Control (TAC) system. This code is caused by an electrical circuit with out-of-range readings or problems that may include poor connectivity, water in the connector, open or shorted circuits, and more. Fixing this trouble code can be done by cleaning the throttle body; replacing components like wiring harnesses, TAC module(s), and/or engine components if necessary; checking for leaks in the connections under the hood; making sure to use proper diagnostic procedures when diagnosing a P1516 code on a car.