AutoCodes – Mercury – P2104 Mercury

P2104 Mercury Code - Throttle Actuator Control System Forced Idle

Quick Answer

The electronic Throttle Actuator Control (TAC) is a DC motor controlled by the Powertrain Control Module (PCM). Common causes include Faulty Throttle Actuator Control (TAC), Throttle Actuator Control (TAC) harness is open or shorted, Throttle Actuator Control (TAC) circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P2104 Mercury indicates Throttle Actuator Control System Forced Idle.
Common causes: Common causes include Faulty Throttle Actuator Control (TAC), Throttle Actuator Control (TAC) harness is open or shorted, Throttle Actuator Control (TAC) circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 2,710

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jun 14, 2020

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P2104 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 P2104 code is set when the Throttle Actuator Control (TAC) system is in the Failure Mode Effects Management (FMEM) mode of forced idle.

OBDII Code P2104 Mercury - Throttle Actuator Control System Forced Idle - AutoCodes.com — P2104 Mercury Code - Throttle Actuator Control System Forced Idle

What does this mean?

What are the Possible Causes of the DTC P2104 Mercury?

Faulty Throttle Actuator Control (TAC)
Throttle Actuator Control (TAC) harness is open or shorted
Throttle Actuator Control (TAC) circuit poor electrical connection
Faulty Powertrain Control Module (PCM)

How to Fix the DTC P2104 Mercury?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

The P2104 code is an informational code only and may set in combination with a number of other codes which are causing the Failure Mode Effects Management (FMEM). If other codes are present, diagnose other codes first.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P2104 Mercury code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P2104 Mercury code?

Need more information on how to fix the P2104 Mercury code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P2104 Mercury code diagnosed by a professional: Find a repair shop in your area

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P2104 Mercury Code

1. What does the OBDII code P2104 mean for a Mercury vehicle?

P2104 indicates that the Throttle Actuator Control (TAC) system has been forced into idle mode due to a detected fault or malfunction.

2. What are the common symptoms of a P2104 code in a Mercury?

Symptoms may include reduced engine power, the inability to accelerate, an illuminated check engine light, and the engine being stuck at idle.

3. What causes the P2104 code to appear on a Mercury?

Common causes include a malfunctioning throttle body, wiring issues in the TAC system, a failed throttle position sensor, or a problem with the engine control module (ECM).

4. Can a dirty throttle body cause the P2104 code?

Yes, a dirty or clogged throttle body can restrict proper airflow and cause the TAC system to force the throttle into idle mode, triggering the P2104 code.

5. How serious is the P2104 code on a Mercury vehicle?

The P2104 code is serious since it can severely limit drivability, leaving the vehicle stuck in idle mode. It should be diagnosed and repaired promptly.

6. What tools are needed to diagnose the P2104 code on a Mercury?

A diagnostic scan tool, a multimeter for testing electrical components, and potentially a throttle body cleaning kit are useful for diagnosing and resolving this issue.

7. Can I drive my Mercury with a P2104 code?

Driving with the P2104 code is not recommended, as the vehicle may have limited power and could become a safety risk if acceleration is needed.

8. How is the P2104 code typically repaired?

Repairs may involve cleaning or replacing the throttle body, repairing damaged wiring or connectors, replacing the throttle position sensor, or reprogramming or replacing the ECM.

9. Can disconnecting the battery clear the P2104 code?

While disconnecting the battery may temporarily clear the code, it does not resolve the underlying problem, and the code is likely to return.

10. How can I prevent the P2104 code from occurring again?

Regularly inspect and clean the throttle body, check for damaged wiring, and follow the manufacturer’s maintenance schedule for the throttle actuator system.