P258B OBD Error Code: Problem & Solutions

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Is there an effect on the vehicle’s fuel economy? Is the brake pedal not responding properly? Do you hear weird sounds from under the car due to vacuum leaks? These symptoms can indicate towards problematic vacuum pump control causing OBD code P258B getting stored in the PCM (Powertrain Control Module).

The vacuum pump used for brake application when modified to perform the additional function of turbocharger may deteriorate the primary application performance. The tapping position and the size of the vacuum port for the auxiliary tank will influence the primary braking performance of the pump. Thus, when the vacuum pump performance is out of order, OBD code P258B gets flashed.

What causes this problem with the Vacuum Pump Control Range/Performance?

• B+ circuit open/fused
• EVP output circuit open/short/high resistance.
• Vacuum supply line open, cracked or torn
• Faulty vacuum pressure sensor
• Electric vacuum pump failure
• Anti-Lock Brake System (ABS) Module might need reprogramming

1. Engine Control Module - If there is any corrosion or breaks in the internal wiring of the harness, then it can cause a short in the ECM or can also cause corrosion in the ECM through the wiring harness. You can always rely on us as we have best auto parts for our customers.
2. Powertrain Control Module - The onboard computer, or powertrain control module is the brain of the engine control system. Now if the brain is not working properly, then neither is the car engine. Get it replaced before the situation gets worse.
3. Electronic Control Unit - Is your car jump starting on reverse polarity? Or are you facing some intermittent starting issues? If yes, then it indicates that your electronic control unit is bad. So, it is very important to replace the defective electronic control unit with us at equitable prices.
4. Diagnostic Tools - Buy quality diagnostic tools to check and diagnose OBD code P258B error with the help of experienced mechanic. Visit us today!
5. Vacuum Pump - When the pump begins to fail, it produces less suction which helps to provide pressure to the brake master cylinder and provides additional pressure inside the brake lines. Thus, the brake pedal becomes hard to press. Replace faulty vacuum pump now!
6. Vacuum Pump Repair Kit - The lack of pressure in the brake system works its way up to the pedal. If there is a lot of pressure, the pedal will be solid, yet very forgiving. When vacuum pressure is low, the pedal is rough and very difficult to press down and engage the brakes. Thus, repair faulty pump parts now!
7. Vacuum Pump Belt - When you recognize a particular warning sign, don't wait to have this item fixed or examined by a professional mechanic. Have a certified diesel mechanic fix this issue as soon as possible. Buy new pump belt immediately.

Interested in knowing the symptoms to OBD code P258B? If yes, then you have arrived at the right place. We at Parts Avatar have listed out few common symptoms associated with Vacuum Pump Control Range/Performance.

Common Symptoms

• Check engine light on
• Lack of fuel efficiency
• Brake pedal not pressing
• Hissing sound due to vacuum leak

Have a look at some ways with which you can correct the P258B code:

• PCM repair and reprogramming
• Electric vacuum pump replacement
• Vacuum pump belt replacement
• Damaged hose replacement
• Damaged/broken wiring and connector replacement

There is no need to get strained if your OBD Code is still flashing up as we are here at your service. Have a look at our superior variety of Electric Vacuum Pump, Vacuum Pump Relay, Vacuum Pressure Sensor, Vacuum Line, ABS Module and many more. Now all your problems would vanish within no time.

Here are some steps which you should follow in order to diagnose this P258B fault code:

• Visually inspect system wiring harnesses and connectors. Focus on harnesses that are routed near hot exhaust pipes and manifolds, as well as those that are routed near sharp edges like the ones found on exhaust shields.
• Search technical service bulletins (TSB) in your vehicle information source. If you find one that matches the symptoms and code/s presented by the vehicle in question, it will very likely aid you in the diagnosis as TSB listings are compiled from thousands of successful repairs.
• Connect the scanner to the vehicle diagnostic port and retrieve all stored trouble codes and freeze frame data. This information is helpful if the P258B proves to be intermittent so write it down for later. Now, clear the codes and see if the P258B is reset.
• If the code is reset, start the engine, allow it to reach normal operating temperature, and then let it idle (with the transmission in neutral or park). Use the scanner data stream to observe vacuum pump input and output data.
• Turn the ignition off. Remove the EVP relay from the relay connector and turn the ignition on to use a 12-volt test light connected to ground, probe the fused ignition RUN/START circuit (terminal 85) at the EVP relay connector.
• Next, the resistance of the EVP relay coil for terminal 85 and 86 is measured by turning the ignition off.
• Disconnect the PCM connector and check the EVP relay connector and the PCM harness connector resistance.
• Check for continuity between ground and the Vacuum Pump relay control circuit at the EVP relay socket.
• Check the vacuum pressure sensor and the brake booster operations. Replace the faulty components immediately.
• Also check for faulty supply line and connector issues and replace them as early as possible.

Common Mistakes When Diagnosing the P258B Code

• Always follow the complete diagnostic procedure without skipping any steps is required as to avoid unneeded repairs. Monitoring the sensor data from the scan tool live data stream is the only way to check for proper operation, and the sensor should not be replaced until it is tested.
• P258B has easily managed symptoms but like any other code, it should be repaired at the earliest convenience. In rare cases where the vehicle runs poorly and the fuel economy goes down, caution is advised when driving to avoid any issues.