Throttle Actuator Control System – Forced Engine Shutdown
Table of contents
P2105 MERCURY Possible Causes
- Faulty Throttle Actuator Control (TAC)
- Throttle Actuator Control (TAC) harness is open or shorted
- Throttle Actuator Control (TAC) circuit poor electrical connection
How do I fix code P2105 MERCURY?
Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector’s pins.
Tech Notes
- The P2105 code is an informational code and may be set in combination with a number of other codes which are causing the FMEM. Diagnose other codes first.
Cost of diagnosing the P2105 MERCURY code
The cost of diagnosing the P2105 MERCURY code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle’s make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.
Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
P2105 MERCURY Description
The electronic Throttle Actuator Control (TAC) is a DC motor controlled by the Powertrain Control Module (PCM). There are 2 designs for the TAC, parallel and inline. The parallel design has the motor under the bore parallel to the plate shaft. The motor housing is integrated into the main housing. The inline design has a separate motor housing. An internal spring is used in both designs to return the throttle plate to a default position. The default position is typically a throttle angle of 7 to 8 degrees from the hard stop angle. The closed throttle plate hard stop prevents the throttle from binding in the bore. This hard stop setting is not adjustable and is set to result in less airflow than the minimum engine airflow required at idle. The P2105 code is set when the Throttle Actuator Control (TAC) system is in the Failure Mode Effects Management (FMEM) mode of forced engine shutdown.