P0458 - OBD Trouble Code

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Check Engine Light on is usually the major symptom visible for OBD code P0458 error. OBD II fault code P0458 is defined as “Evaporative Emission System Purge Control Valve Circuit Low Input”, and is set when the PCM (Powertrain Control Module) detects that a part of the evaporative emission control system is not functioning as it should.

The PCM interprets fluctuations of the pressure in the evaporative emission control system as variations in the system reference voltage. The base reference voltage may differ between applications, but in all cases, the PCM in any particular application will store a fault code when it detects a reference voltage that is lower than expected, given the current pressure/flow in the system. Note that some applications require several malfunctions before the Check Engine light will illuminate. In cases where no illuminated warning lights are present, it might be possible to read fault codes as “pending codes.”

The purpose of the Evaporative Emission Control System is to prevent fuel vapours from escaping into the atmosphere. To achieve this, fuel vapours from the tank are collected and passed through vacuum lines (using the engine vacuum) either to the inlet tract through the throttle body to be combusted, or to a charcoal canister that absorbs the vapours.

What causes this problem with the EVAP Purge Control Valve Circuit Low?

• Defective purge control solenoids
• Defective flow/pressure sensors
• Open circuits
• Shorted, burnt, damaged, or corroded wiring/connectors
• Vacuum leaks in associated hoses and lines
• Failed, or failing PCM

1. Fuel Tank Filler Neck - Sometimes, the filler neck can be faulty and might need replacement. Buy new tank filler neck now!
2. Fuel Tank Vent Valve - Check for damaged fuel tank vent valve and replace if as required. Buy new vent valve now!
3. Vapour Canister Valve - Vapour canister valve can be faulty and can cause performance issues. Buy new canister valve now!
4. Fuel Tank - Check of leaky or clogged or damaged fuel tank and replace it immediately. Buy new fuel tank form us.
5. Fuel Tank Cap - Fuel tank cap should be tightened properly and should be replaced if damaged or missing. Buy new tank cap now!
6. Diagnostic Tools - Quality OBD scanner and tools is required to resolve this OBD issue. Buy new diagnostic tools from us.

If you are facing OBD error code P0458, then there are significant common symptoms that can be felt or observed. We have worked out a list here to help you out in understanding this problem better.

Common Symptoms

• Check Engine Light On
• Noticeable fuel odor caused by the release of fuel vapours
• Reduced fuel economy

Have a look at some ways with which you can correct the P0458 code:

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:

• Faulty purge control solenoid replacement
• Repair, clean, or replace a broken, clogged, or faulty charcoal canister
• Faulty vacuum hoses replacement
• Faulty fuel vapour hoses replacement
• Faulty pressure/flow sensor replacement
• Replacing or repairing an open or shorted EVAP purge control solenoid harness

If you need any parts to fix this problem you can easily find them with us. Not only that we also have in stock the best in range auto parts and that too at the most budget friendly prices ever online. Whether you need a Fuel Tank Filler Neck, Evaporative Vent Valve, EVAP Purge Switch, Carbon Canister, Fuel Tank, Fuel Cap you can simply rely on us for quality auto parts.

Here are some steps which you should follow in order to diagnose this fault code:

Record all fault codes and available freeze frame data for future reference should an intermittent fault be identified later on. Next, inspect the fuel filler cap, and replace it if there is the slightest doubt about its condition and fitment. If the cap is replaced, clear all codes, and operate the vehicle to see if the code returns.

If the fuel filler cap is good, but the fault persists, perform a thorough visual inspection of all wiring and connectors in the control circuit. Look for damaged, shorted, or corroded wiring/connectors, and repair or replace as required.

If the fault persists, consult the manual to determine the location, color-coding, and function of each wire in the control circuit, and perform continuity, resistance, and reference voltage checks on the control circuit. Be sure however to disconnect all control modules before performing continuity checks to prevent damage to the modules. Compare all obtained readings with values stated in the manual. Make repairs as required, and repeat all checks to ensure that all obtained readings fall within the manufacturer’s specifications.

If all wiring, connectors, and the purge valve solenoid check out fine but the fault persists, suspect either a vacuum leak in the system, or a clogged charcoal canister. Both scenarios are equally likely, so if you have not done so at the beginning of the diagnostic procedure, now would be a good time to remove and inspect the charcoal canister for signs of corrosion.

Since the canister is located under the car, close to the fuel tank, there is a good chance that corrosion ad taken hold in it, thus preventing its proper operation. If there is any doubt about the condition of the charcoal canister, or if there is evidence of the canister being clogged or damaged in any way, replace it. Clear all codes, and operate the vehicle to see if the code returns.

If the canister is good, but the fault persists, place the vehicle on a hoist with the engine running, and allow the system enough time to come into operation. If a suitable scanner is available, monitor the live data stream; the canner will indicate when the PCM commands the purge control solenoid to open. However, confirm the reading by listening for an audible “click” as the solenoid cycles.

If a visual inspection dos not reveal vacuum leaks, the system must be double-checked with the aid of a smoke machine. Locate the vacuum supply hose in the system, and connect the nozzle of the smoke machine to it. Allow the system to fill with smoke; as the purge solenoid cycles, smoke will be drawn into the system.

Keep a sharp lookout for smoke that escapes through small, previously undetected leaks. Smoke cannot escape from a smoke-proof system; where you see smoke, there is a leak, so mark the position of the leak for repair. Repair all leaks found with the smoke machine, but rather replace entire lengths of vacuum line between factory-fitted joints and connections, than attempt to repair leaks. Repairs often start leaking soon due to vibration.

If the code returns despite all repair attempts, it is likely that there is an intermittent fault present. Intermittent faults can sometimes be extremely challenging to find and repair, meaning that the fault may have to be allowed to worsen before an accurate diagnosis, and definitive repair can be made.

Common Mistakes When Diagnosing the P0458 Code

Always check for the following components;

• Fuel Tank Sending Unit defects
• Defective or damaged Fuel Tank
• Fuel Tank Pressure Sensor, wiring, or computer faults
• Carbon Canister faults
• Defective Canister Vent Valve which might not open