The gas pedal is a simple piece of linkage connecting the driver to the more complex throttle and throttle body. It is with this linkage that the throttle or computer makes all of its adjustments based on driver demands for speed. If the linkage is unresponsive, several factors can be the cause. Here, depending on the make and model of your vehicle, we can begin to diagnose and recommend repairs for your unresponsive gas pedal. Always remember when diagnosing any issue, start with the most common issues first.
- Note: Keep in mind that not all of the steps and sections of the guide will pertain to your specific make and model. There are a variety of throttle designs and a variety of different parts to accompany them.
Part 1 of 2: Visibly inspect the gas pedal
Upon initial inspection, there are a few issues that will have defects visible to the naked eye. Always start with the simpler fixes before jumping to the worst possible scenario.
Step 1: Look for visible obstructions of the gas pedal. Look for any obstructions or objects getting in the way of the pedal. Has anything rolled under the pedal? Is there a cord tangled in the way? Pull away the floor mat and make sure it was not causing resistance.
Step 2: Look for visible obstructions of throttle. Open the hood and look for the throttle body. The throttle body may be exposed, while some will need to have parts removed for access.
Look for physical matter, extreme sludge build up, an obstruction of some sort, or a broken throttle body.
Step 3: Look for visible damages or deformities in system. Look at the linkage on the drive side of the firewall to see if the linkage straight and aligned properly.
Look at the linkage in the engine bay to see if the throttle linkage is straight, intact, and tight. Any extra slack, bends, or breaks in the linkage will cause a variety of throttle issues.
Assuming the throttle body, cable, and pedal are all functioning properly, you will need to look further into the system and its components to diagnose the unresponsive gas pedal. Listed next are some of the common issues that will cause similar symptoms.
Part 2 of 2: Consider the most common issues
Without any major defects in the throttle components, chances are your issue(s) will stem from something harder to determine. The quickest way to diagnose the issue will be through a process of elimination involving the following components. You may be able to eliminate new parts that have been replaced recently, or components you know are working correctly.
If you have not do so, get the OBD codes scanned for help pointing you in a good direction. You can have this done at most automotive part stores nationwide.
Step 1: Consider the throttle position sensor. A dirty or clogged throttle position sensor will not take accurate readings nor give accurate outputs for the computer to use. This can cause dangerous outcomes for the driver.
These are typically accessible and capable of being cleaned. If this is the cause of your issues, a simple cleaning should suffice. Worst case scenario you will need to replace the entire unit.
Step 2: Check for a clogged fuel filter. A clogged fuel filter will not allow the amount of fuel demanded to make it to the engine on time. A driver can press the gas pedal, and all of the throttle components may be demanding the correct amount of fuel, but the pump is facing resistance at the filter and cannot allow the flow to go through to the engine.
If the fuel filter is clogged, the only repair that can be made is to replace the filter. They are not serviceable units.
Step 3: Check for a faulty fuel pump. A faulty fuel pump will not push the gas needed into the lines and to the engine. Again, if this is the case, all of the throttle components may be working correctly but seem as if they are not responding.
To repair the fuel pump, you will want to drop the tank or access it through the access panel (if equipped). Look at the condition of the pump and make sure there are no major clogs on the intake. Assuming the pump is clean, and has failed, you will need to replace the entire fuel module. Older vehicles may have a separate pump, but most modern vehicles will include all parts into one module.
Step 4: Check the mass air flow sensor. The mass air flow sensor will tell the computer what amount of air is being taken into the engine to match it with the proper amount of fuel. The air fuel mix is critical for engine performance. If the sensor has failed and the wrong amount of air and fuel are being delivered to the engine, the driver demands will have little control over the engine. This may come off as an unresponsive gas pedal.
These are usually not serviceable, but will need to be replaced if faulty. This can be done easily, and will likely need to be done on an aging vehicle.
Step 5: Look at the electronic throttle control module. Electronic throttle controls module faults are one of the most common issues when dealing with a unresponsive gas pedal.
This is a sensor that reads how far you have pressed the gas pedal down and outputs that information to the computer which controls the throttle. This information is also used in computing ignition timing and other components.
If the module has malfunctioned, the car will operate in a “Limp Mode.” This is a function that allows the car to be run at a low speed in order to move the vehicle from hazardous areas. There are other symptoms that will cause similar issues with the throttle.
If the electronic throttle control module has malfunctioned, you will need to replace one or all of the components involved. Further testing is needed. Home repairs on these systems are not recommended.
A non-responsive gas pedal can be very frustrating and leave you asking many questions. With the right knowledge a confusing issue can becoming crystal clear. If your vehicle is in Limp Mode or not functional, have a professional mechanic, such as one from YourMechanic, inspect your gas pedal for you.
This article originally appeared on YourMechanic.com as How to Troubleshoot a Car That Doesn't Respond to The Gas Pedal and was authored by Jessica Howe.