What Does P258B Mean?
The vacuum pump is operating outside expected performance parameters. The PCM detects that vacuum pressure is not being generated or maintained as expected, indicating pump inefficiency or system leaks.
Safety Warning
Reduced or absent brake assist will result in hard brake pedal and increased stopping distances. Vehicle should not be driven until repaired.
Common Causes
35%
Worn vacuum pump failing to generate adequate vacuum
30%
Vacuum system leaks in lines or check valve
15%
Clogged vacuum pump intake filter or restriction
12%
Faulty vacuum pressure sensor giving incorrect readings
8%
Excessive vacuum demand from leaking brake booster
Diagnostic Steps
1
Step 1: Connect vacuum gauge to system and verify actual vacuum levels produced
2
Step 2: Inspect all vacuum lines for cracks, disconnections, or deterioration
3
Step 3: Test check valve operation and verify it holds vacuum when pump stops
4
Step 4: Monitor vacuum pump duty cycle and current draw during operation
5
Step 5: Perform vacuum pump output test and compare to specifications
Estimated Repair Cost
$250 - $1,000
Parts + labor, varies by vehicle and location
The vacuum pump is operating outside expected performance parameters. The PCM detects that vacuum pressure is not being generated or maintained as expected, indicating pump inefficiency or system leaks.
The most common cause of P258B (Vacuum Pump Control Range/Performance) is: Worn vacuum pump failing to generate adequate vacuum
Typical repair costs for P258B range from $250 to $1,000, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Reduced or absent brake assist will result in hard brake pedal and increased stopping distances. Vehicle should not be driven until repaired.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P258B to identify the root cause.
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Quick Info
Category
Powertrain
System
Vacuum System / Brake Assist
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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