Vacuum Pump Control Range/Performance
The P258B code indicates that the Engine Control Module (ECM) has detected a vacuum pump control circuit performance issue, typically related to the vacuum pump used for brake boost or other vacuum-operated systems. This can be caused by a faulty vacuum pump, a stuck or leaking vacuum control solenoid, wiring issues, or a malfunctioning ECM. The pump may not be generating sufficient vacuum or may be operating outside its expected parameters, affecting brake assist and other systems.
1. Most Common Causes
- Faulty vacuum pump
- Stuck or leaking vacuum control solenoid
- Wiring or connector issues in the vacuum pump circuit
- Failed ECM
2. Symptoms You Will Notice
- Hard brake pedal (reduced brake assist)
- Check Engine Light illuminated
- Vacuum pump running continuously or not at all
- Possible hissing noise from vacuum leak
3. Step-by-Step Diagnosis
Step 1: Scan for additional codes and freeze frame data.
Step 2: Visually inspect vacuum pump, hoses, and electrical connectors for damage or leaks.
Step 3: Test vacuum pump operation using a scan tool to command it on/off and measure vacuum output.
Step 4: Check vacuum control solenoid resistance and operation with a multimeter.
Step 5: Inspect wiring and grounds for shorts, opens, or corrosion.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive with this code as it can lead to reduced brake assist, increasing stopping distance and risk of accident. Have the vehicle inspected immediately.
How much does it cost to fix?▼
Repair costs typically range from $150 to $400, depending on the cause. A vacuum pump replacement can cost $200-$350, while solenoid or wiring repairs may be less.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.