How to Fix Code P0297: A More In-Depth Guide

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vehicle speedometer showing overspeed

If your car throws the code P0297 up on its display, it could be because of several different problems. You need to determine how long the vehicle has been having this issue and how often it's happening. This will help determine what needs fixing to get rid of that pesky error message!

This guide will help you diagnose and repair the problem with your car's power steering system causing code P0297.

What is the Code P0297?

The P0297 code is a generic powertrain code. It means that it's something to do with how the engine works, not necessarily how it is explicitly performing. In this case, P0297 refers to a "Post Catalyst Fuel Trim System Too Rich" error. 

This means the car has too much fuel after passing through the catalytic converter, indicating the actual vehicle speed has exceeded the maximum allowable limit.

Causes of Code P0297

The common cause of this code is driving the vehicle at too high a pace. Because most automobiles have a limiter that limits acceleration beyond a certain point, some drivers will accelerate to the limit and then cruise downhill to obtain quicker speeds. 

However, this will cause the P0297 code to be set and the Check Engine Light to illuminate. Several sensors (wheel speed sensors and the vehicle speed sensor) constantly check the vehicle's speed, and the code is set as soon as a limit is exceeded. In other cases, though, a malfunctioning speed sensor is at blame.

How to Fix Code P0297

If it happens your car is showing the code P0297, don't jump to conclusions and spend a lot of money on unnecessary repairs. There are four ways to troubleshoot and fix this code:

1. Clear the Code

One way to try and correct the problem is to clear the code and see if it comes back. You can perform it by pressing the brake pedal and turning the ignition off for five seconds. You should then start the engine and drive the vehicle normally.

If the code does not come back, it may mean that you have fixed the problem. You do not need to take any further action. However, if the code does reappear after driving the car, you should take your vehicle to a mechanic for further inspection.

2. Clean and Check the VSS

The speedometer uses the vehicle speed sensor (VSS) to determine how fast you are going. This sensor is responsible for sending the speed of your vehicle to the ECU so it can correctly calculate how much fuel to inject. A faulty VSS can cause an issue with your check engine light as well as a P0297 code. To check the VSS:

  • Unplug the electric connector from the VSS.
  • Check all the connectors for any signs of damage.
  • Clean the connector if it is dirty or corroded.
  • Plug the electric connector back into the VSS.
  • Start your vehicle engine and check to see if the code reappears.

3. Examine the Reference Voltage and Ground Circuits

P0297 is a reference voltage circuit problem, which means there could be an issue with the power supply to your VSS or how it is wired in. First, check the following:

  • Ensure that all wiring connections are secure and not corroded.
  • Check for proper ground on each side of the VSS.
  • Check for adequate power supply to the VSS and how it is wired in.

If none of those ways work, it may be time for a new VSS or Vehicle Speed Sensor. It is responsible for sending the PCM the correct speed information. If you still have a code related to the Reference Voltage Circuit, replace your existing VSS with a new one.

4. Replacing the VSS

If cleaning and checking do not fix your problem, you may need to replace the VSS itself. Some vehicles have a built-in fuse for this sensor that can cause problems, so you should check how many amps it is rated at to be sure. 

If all else fails, take your vehicle to a mechanic to have them replace it for you. However, if you are confident enough to do it your own, we hope these steps were of some help.

Remove the faulty sensor

  • Remove the negative battery cable by loosening it.
  • Disconnect the speed sensor connector from the malfunctioning speed sensor.
  • Remove the sensor by unscrewing it.

Double-check the connector wiring for any breakage or exposed wires. It is preferable to replace a broken connector, although it is not required if the connector fits snugly onto the sensor. Repair any exposed wires with electrical tape.

Install the new sensor

  • Make that the O-ring on the new sensor is in place.
  • Replace the sensor and tighten it. These sensors are easily broken, so don't overtighten them.
  • Connect the electrical connector to the speed sensor.
  • Connect the negative battery cable and tighten it.
  • After replacing the VSS, use your diagnostic car tool to see if the P0297 has been cleared.

Common Mistakes When Diagnosing the CodeP0297

There are several mistakes when diagnosing the P0297 code, and one of the most common is replacing the vehicle speed sensor without thoroughly diagnosing the problem. The common cause of the error code P0297 is that the driver has been driving the vehicle too fast. Therefore, you shouldn't jump to conclusions quickly and replace parts without verifying the problem.

Another mistake is when the technician believes that the only way to repair this code is by replacing the VSS. There are several ways to fix P0297, and it does not always require the replacement of the sensor.

Code P0297 FAQ

1. How does a tool diagnose the code P0297?

P0297 codes usually reset at average motor speeds. It's next-and-easy for you to scan your car speed sensors and if you want some more information. This can be achieved by having help take care of drivers while they're reading the scanning software

If the speed sensor receives an excessive amount of vibration at high speeds, this should result in a malfunctioning speed detector. Usually, the problem involves drivers operating cars at a speed that exceeds automaker specifications, and it happens with sloppy coding codes, which cause problems.

2. How serious is the P0297 code?

P0297 codes are generally relatively safe in the same situation as speed problems. In this way, there will usually be a code being cleared as long as the car never carries the driver's maximum speed. 

It should therefore get replaced immediately when the sensors require updating. It is supposed to cause everything from the timer information and the speedometer readout to engines operating properly.

3. When is the P0297 code detected?

The ECM is detected when a vehicle is in an over-speed condition.

4. What are the symptoms of P0297?

The error code P0297 does not show any signs aside from the check engine light.

5. What is the most effective way to repair the P0297 code?

The most typical fix is clearing the code and reminding the driver not to exceed the speed limit. However, it's possible that the speed sensor has to be replaced or shorts or openings in the sensor's circuit that need to be fixed.


If you're experiencing the code P0297, it’s best to diagnose it right away and address the issue. We hope this has helped relieve some of your troubles. This is just one in a long list of common car problems and how to fix them. We want to help ensure that you don't have to worry about what they mean or how to get it fixed when these issues arise!