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P0458 is a diagnostic trouble code (DTC) for "Evaporative Emission System Purge Control Valve Circuit Low". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.
The P0458 code means that a specific part of the EVAP system purge control valve circuit has caused a voltage reading that does not match the manufacturer’s specifications, and is therefore malfunctioning in some way.
When this code is detected by the OBD-II scanner, it means that there is an issue with the EVAP emissions system. This system controls the rate of vapor from the canister with a system purge control valve. Part of the circuit system for this valve measures and reports voltage to the PCM. If this reading is lower than the manufacturer’s specifications, the PCM assumes that there is a fault in the circuit, and stores the P0458 code.
In many cases, this code could be present due to an improperly installed fuel cap. However, there may be more complex issues behind this code, including:
Most of the time, there will be no other symptoms present when the P0458 code is present. The Check Engine Light may be lit, and there may be other codes stored in the PCM relating to the EVAP emissions control system.
The first step to diagnosing the issue behind the P0458 code is to verify the code with an OBD-II scanner, and to check for other codes present. Similar or related codes may reveal a larger issue that should be addressed first.
After verifying, the next step is to perform a visual check of all the electrical wiring and components, to ensure that there is not a loose, shorted, or corroded wire that is causing the PCM to receive a faulty signal. Additionally, the mechanic may wish to check that the fuel cap is installed properly, because this is frequently a simple reason for the presents of the P0458 code.
Once these inspections have been performed, the code should be cleared and the system retested. If the code returns to the PCM, then the mechanic has diagnosed a larger issue with the EVAP emissions system purge control valve circuit, and should move on to further repairs.
The most common mistake made when diagnosing the P0458 code is to replace system components without first inspecting the fuel cap or the vacuum hoses for improper installation or leaks. A thorough diagnostic procedure should be performed before system components are replaced.
The P0458 code does not represent a serious issue that will affect the operation of the vehicle; however, its presence may cause a vehicle to fail an emissions test. If the P0458 code is detected, it should be addressed at the next routine servicing if not before.
After checking and repairing the electrical wiring, connectors, and other components, and ensuring that the fuel cap is properly installed and not damaged, the mechanic may perform other repairs that include:
After each repair is made, the code should be cleared from the PCM and the system should be retested. This process allows the mechanic to eliminate potential causes until they discover exactly what was causing the code to be stored.
YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.