P1516 on 2006-2011 Buick Lucerne — Throttle Actuator Control (TAC) Module — Throttle Actuator Position Performance (GM)
1 vehicles · 1 makes · $250-$600 repair
Most Reported On
P1516 is an OBD-II diagnostic trouble code meaning “Throttle Actuator Control (TAC) Module — Throttle Actuator Position Performance (GM).” P1516 is a manufacturer-specific code used mainly by General Motors vehicles (Chevrolet, GMC, Buick, Cadillac, Hummer, Saturn), where it means the electronic throttle system's actual throttle plate position doesn't match what the computer commanded. In a drive-by-wire system, the ECM reads the accelerator pedal sensors and drives a motor on the throttle body to open the throttle; if the throttle position sensors report a position that disagrees with the command for more than about a second, this code sets. Drivers typically see a "Engine Power Reduced" message with the check engine light, and the vehicle drops into limp mode with sluggish, limited acceleration; some trucks set the code with no symptoms at all. Because throttle control directly affects your ability to accelerate, it should be diagnosed promptly rather than driven around. Note that the definition differs by manufacturer: Ford uses P1516 for an Intake Manifold Runner Control (IMRC) input error on Bank 1, while Honda/Acura use a throttle actuator position definition similar to GM's. This code is most commonly reported on 2006-2011 Buick Lucerne, with repair costs ranging from $250 to $600.
Common Causes
Typical Repair Cost
Based on 1 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
To diagnose P1516, you'll need an OBD-II scanner. Here are our recommendations at every price point.
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FAQ
What does P1516 mean?
P1516 stands for "Throttle Actuator Control (TAC) Module — Throttle Actuator Position Performance (GM)." P1516 is a manufacturer-specific code used mainly by General Motors vehicles (Chevrolet, GMC, Buick, Cadillac, Hummer, Saturn), where it means the electronic throttle system's actual throttle plate position doesn't match what the computer commanded. In a drive-by-wire system, the ECM reads the accelerator pedal sensors and drives a motor on the throttle body to open the throttle; if the throttle position sensors report a position that disagrees with the command for more than about a second, this code sets. Drivers typically see a "Engine Power Reduced" message with the check engine light, and the vehicle drops into limp mode with sluggish, limited acceleration; some trucks set the code with no symptoms at all. Because throttle control directly affects your ability to accelerate, it should be diagnosed promptly rather than driven around. Note that the definition differs by manufacturer: Ford uses P1516 for an Intake Manifold Runner Control (IMRC) input error on Bank 1, while Honda/Acura use a throttle actuator position definition similar to GM's.
What are the most common causes of P1516?
The most common causes of P1516 are: Faulty throttle body / throttle actuator motor (the most common fix on GM trucks and SUVs), Dirty or carbon-fouled throttle body causing the throttle plate to stick or move erratically, Poor engine ground connections (corroded GM ground points G103/G104 causing voltage drop above 0.1V), Damaged wiring or corroded connectors in the TAC motor control or throttle position sensor circuits, Faulty throttle position sensor(s) on the throttle body, Failed stand-alone TAC module (separate module on 1999–2005 GM trucks), ECM/PCM fault, or a needed throttle relearn after cleaning or battery disconnect. The specific cause varies by vehicle.
How much does it cost to fix P1516?
Repair costs for P1516 range from $250 to $600, depending on the vehicle and root cause.
Which vehicles are affected by P1516?
Au7o has documented P1516 across 1 vehicle models from 1 manufacturers: Buick.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.