Technical Description of OBD-II Trouble Code
Forced Idle in Throttle Actuator Control System
What does that signify?
This generic powertrain diagnostic trouble code (DTC) is applicable to all OBD-II equipped vehicles that utilize a drive-by-wire throttle control system, including but not limited to vehicles from Ford, GM, Toyota, Dodge, Chevy, Subaru, etc. Anecdotally, this code appears to be more common in Ford vehicles compared to other brands.
The P2104 OBD-II trouble code is one of several codes that indicate the Powertrain Control Module (PCM) has detected a malfunction and is restricting the operation of the Throttle Actuator Control System.
This situation is known as activating a fail-safe or limp mode to prevent the engine from accelerating until this malfunction is corrected and the associated code is cleared. There are four codes referred to as force codes, namely P2104, P2105, P2106, and P2110.
The PCM sets these codes when other codes are present that indicate an issue that may be safety-related or cause damage to the engine or drivetrain components if not addressed promptly.
Code P2104 is set by the PCM to force the Throttle Actuator Control System to remain at idle.
This code can be related to a malfunction in the Throttle Actuator Control System, but usually, another issue triggers this code. Trouble code P2104 is triggered by the PCM when it receives an abnormal signal from various components. The Throttle Actuator Control System is duty cycle controlled by the PCM, and the system’s function is limited when other fault codes are detected.
Code Severity & Symptoms
The severity of this code can range from moderate to severe, depending on the specific malfunction. Symptoms of a P2104 trouble code may include:
Common Causes Of This DTC Code
The most common situations that trigger this code and put the engine in fail-safe or limp mode to indicate an issue and act as a warning are:
What are some common repairs?
Diagnostic and Repair Procedures
The first step in the troubleshooting process for any malfunction is to research the Technical Service Bulletins (TSB’s) for the specific vehicle by year, model, and power plant. In some circumstances, this can save a lot of time in the long run by pointing you in the right direction.
The second step for this code is to complete a PCM scan to identify other trouble codes. This code is an informational code, and in most circumstances, its function is to alert a driver that the PCM has initiated a fail-safe mode because of a malfunction or failure in a system that is not directly related to the Throttle Control Actuator.
If other codes are identified, you should check for TSB’s related to the specific vehicle and that code. If a TSB has not been generated, you should follow the specific troubleshooting steps for that code to pinpoint the source of the malfunction that the PCM is detecting to put the engine in fail-safe or limp mode.
Once all other codes have been cleared or if no other codes are detected, if the Throttle Control Actuator code still exists, the PCM and Throttle Control Actuator should be evaluated. All wiring and connections should be visually inspected for obvious defects as a starting point.
Common Mistake
Replacing the Throttle Control Actuator or PCM when other malfunctions are triggering this code.
Rare Repair
Replace Throttle Actuator Control
Hopefully, the information in this article has been helpful in pointing you in the right direction to resolve the problem with your Throttle Actuator Control System force code. This article is strictly informational, and the specific technical data and service bulletins for your vehicle should always take priority.
External Links
Here are links to some discussions of Ford vehicles with the P2104 code:
