Causes and Fixes Chevy P1516 Code Reduced Engine Power

Most often, the message Reduced Engine Power will display, and there is no power when the pedal is pressed.

An OBDII scan tool will usually give a P1516 error code which is a “Throttle Actuator Control Module Throttle Actuator Position Performance.”

What is a Chevy P1516 OBDII Error Code?

A Chevy P1516 OBDII error code is a “Throttle Actuator Control Module Throttle Actuator Position Performance.”

When the code is given, the dashboard often will display Reduced Engine Power.

The onboard computer (PCM) is having an issue with the throttle position, which is used to control the air-fuel ratio mixture going into the engine.

Causes and Fixes Chevy P1516 Code Reduced Engine Power

1. Throttle Body


A bad or dirty throttle body can cause a P1516 error code.

If it is dirty, cleaning it with throttle body cleaner often can help clear errors.

If cleaning does not help, it may need to be replaced, as an internal component may have failed.

2. TPS Pigtail


The Throttle Position Sensor (TPS) pigtail wiring harness can cause a problem.

Check the harness for any loose wires or bad connections.

Sometimes unplugging it and plugging it back helps to get a good connection.

If the pigtail keeps giving an issue, it can be replaced with a new one.

3. Throttle Position Sensor


A failing throttle position sensor is another common problem.

It is located on the throttle body and can be replaced with a new unit if it has failed.

Keep in mind a bad pigtail will cause the same issues as a bad throttle position sensor.

4. Bad Ground


A bad ground wire between the onboard computer, engine, and position sensor has been known to cause issues with a Chevrolet P1516 code.

If you have a Chevy with a very problematic reduced engine power and P1516 code, often it is a bad ground wire.

In some cases, all the major components are replaced, and the code comes back later or intermittently there is likely a bad ground wire.

A new ground wire can be run between all the components to be sure there is a good connection.

The onboard computer is the most important part of running a new ground wire which can be attached to the outer case.

5. Accelerator Pedal Sensor


The accelerator pedal sensor can also cause an issue if it fails.

It is located under the dashboard on the pedal.

A new unit can be installed if it has failed.

Summary
If you have a Chevy with a Reduced Engine Power error message and a P1516 code, this can at times be an easy fix and, other times, problematic.

A P1516 code is a known problem with Chevrolet that often has different fixes.

Often cleaning up the throttle body with cleaner will clear the error and solve the issue.

Other times it can be the throttle position sensor harness or sensor itself.

If all else fails, there is a known problem with the ground wire between the computer and engine block.

Many Chevrolet sensors report solving the issue by running a new ground wire.