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What is Engine Failsafe Mode on Ford F150?

What is Engine Failsafe Mode on Ford F150?

Ford F150 comes with a failsafe mode to protect itself during damage to any vital part, including the engine and transmission system.

What is Engine Failsafe Mode on Ford F150? The engine control unit (ECU) of the Ford F150 enables the failsafe mode by reducing its accelerating and gear shifting capabilities when it receives a signal from any sensor beyond the safe limits. Its purpose is to allow the truck to safely reach the home or workshop without further damage to the engine or any other vital part due to fault. You have to run an onboard diagnostic (OBD II) tool to read the trouble codes and take action accordingly.

We will discuss failsafe mode causes, symptoms, and how to resolve the problem or remedial measures to take the truck out of the state to restore its full capabilities.

Engine failsafe mode on Ford F150

Modern vehicles come equipped with various electronic sensors to monitor the performance of the ignition system, transmission components, fuel system, brakes, tire pressure, stability control system, and throttle body control.

These sensors send signals to a central computer known as ECU, ECM, or PCM. It evaluates the signals from all sensors and compares them with predefined limits through a complex algorithm.

In case of no input or signal beyond acceptable range from a particular component, ECU enters a failsafe mode by allowing only a few options regarding the truck’s speed, acceleration, and gear shifting.

This safety feature aims to protect the faulty system and other connected components from catastrophic failures. In this way, the fault severity level will remain minor and save repair costs and downtime.

However, in case of an error signal from the engine or fuel system, this mode will disable the fuel pump or starting the truck, and you won’t be able to drive it.

Causes of failsafe mode on F150

There are several causes for the activation of failsafe mode on the Ford F150. Sometimes it is due to genuine reasons in the form of fault in any component or sensor sending the signal.

However, it can be a false indication that you can resolve by resetting the ECU a few times. 

Failure of engine component

The engine is the most critical part of a pickup truck. Mechanical failure in any of its elements will turn the failsafe mode ON by limiting its power. The engine has a compact assembly with several parts like pistons, fuel injectors, valves, and its lubrication mechanism moving very fast.

Therefore, this mode comes into play when any sensors measuring temperature, oil pressure, or solenoids moving the valves sense any abnormality. In severe cases, it will block the engine ignition, and you won’t be able to start it until the rectification of the fault.

Any auxiliary system, including air intake or throttle body malfunction, can also cause the problem. Therefore, you should check for any choked air filter, carbon deposition on the throttle body valve, or position sensor to identify the problem.

Faulty transmission system

Transmission is part of the drivetrain and has a vital role in shifting power from the engine to the wheels. It consists of several gears enclosed in a box that requires sufficient lubrication to prevent heating problems.

Therefore, any fault in transmission hindering smooth-shifting due to broken gear teeth or other mechanical issues or heating of the parts due to low transmission fluid can result in check engine light indication on the dashboard.

Moreover, Ford F150 will fix itself in a single gear, and you will be able to move it to the workshop or any safe place only.

Problems in the fuel system

Any mechanical fault on the fuel pump or leakage in the fuel lines will result in low fuel pressure on the engine. ECU or PCM will put the F150 to the failsafe mode by cutting off its full power.

Failed fuel injectors unable to supply sufficient fuel to combustion chambers can also be another reason for the truck to go into the condition with no ignition/no start.

There can also be problems in the fuel filter/strainer, issues with the motor of the fuel pump, and any mechanical damage to the pump impeller. 

Sensor fault

Modern vehicles have pressure, temperature, and speed sensors to measure these parameters at various critical components. Any malfunctioning sensor can send a false signal to the PCM resulting in a fault code, and the F150 can go into failsafe mode.

Moreover, it controls various engine parameters like fuel intake, air pressure, oil pressure based on the input from the sensors. Therefore, you need to run the OBD-II tool to get the fault code and the reason behind the fault causing the truck to go into failsafe mode.

Few examples driving this condition are the O2 sensor, manifold absolute pressure (MAP) sensor, and mass airflow (MAF) sensors.

ECU fault

ECU or PCM is the computer that acts as the brain of the Ford F150, monitoring its performance and guiding all components to work efficiently. It has semiconductor chips and microprocessors prone to failures due to heat, moisture, and shocks.

Therefore, ECU can also become faulty due to a power glitch or any of such faults. It can result in reduced engine performance and check engine light ON condition resulting in failsafe mode.

Sometimes, any power glitch can cause the ECU to read a false signal from a particular sensor or be stuck in a programming loop, causing the fault. Therefore, you need to turn it OFF for 20-30 seconds and then start the truck to see if it resolves the error.

Brakes problem

The latest vehicles have advanced hydraulic brakes with sensors to monitor the health of the system. Any fluid leakage, low pressure, or excessive heating of the brake discs can result in fault indication by ECU.

In severe cases, your pickup truck can enter the failsafe mode by limiting the speed so that you can control it even with a faulty braking system.

How to diagnose and resolve the failsafe mode on Ford F150?

The easiest solution to resolve the failsafe mode is to restart the complete truck system. Turn Off the Ford F150 for 20-30 and turn it ON to see whether the fault is gone or persists.

If this happens frequently, visit the Ford dealer or authorized workshop to run the OBD-II tool to get the fault codes. They have service manuals to check the interpretation of those codes and check the relevant systems only.

In the case of ECU throwing multiple codes, it can probably be the computer’s fault, and you need to replace it. The cost involved can vary from $200-$1000 depending on the faulty component.

Fault codes during failsafe mode

Fault codes during this mode can vary according to the model, trim level, and manufacturing year of the F150.

A few examples of diagnostic trouble codes (DTC) in the condition are P0135 and P0155 related to the O2 heater circuit, P0010 related to intake camshaft position actuator and P2119 is for throttle body position sensor.

In addition, there can be several other codes specific to each part of a system. Experienced mechanics maintain a logbook of the frequently occurring trouble codes and associated remedial measures to save time.

Is failsafe mode the same as a limp mode on Ford F150?

Failsafe mode is a safety feature to protect the engine from severe level faults. An informal name for such an engine state is limp mode because of the limited performance of the truck.

A more technical term for the mode is the engine cut-off safety feature. It trims its performance features to a safe level to protect it from further damage.

Is engine failsafe mode good for the truck?

Engine failsafe mode on F150 is a serious situation and is a blessing in disguise. Its purpose is to protect the engine or transmission parts from further damage.

ECU tries to limit or, in some cases, stop the engine to prevent its self-destruction due to any mechanical or electrical fault. Therefore, in some sense, it is good to keep the fault level low or minor, minimizing the repair cost.

Can you drive the Ford F150 during failsafe mode?

During failsafe mode, ECU will limit the engine performance. However, it will enable you to move at reduced speed and in a single gear in most cases.

In this way, you will reach the workshop without causing severe damage to the engine or other vital parts of the Ford F150.

In other cases with faulty fuel systems or sensor faults, the engine will go into crank or no start state, and you won’t be able to drive it.

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