Vacuum Pump Control Circuit/Open
The P258A code indicates a fault in the vacuum pump control circuit, typically found in vehicles with electronic vacuum pumps used for brake boost or other systems. The powertrain control module (PCM) has detected an open or malfunction in the circuit that controls the vacuum pump relay or the pump itself. This can lead to reduced vacuum assist, affecting braking performance and other vacuum-dependent systems.
01. Most Common Causes
- Open or shorted wiring in the vacuum pump control circuit
- Faulty vacuum pump relay
- Failed vacuum pump motor
- Blown fuse or fusible link
- Corroded or loose electrical connectors
02. Symptoms You Will Notice
- Illuminated Check Engine Light
- Hard brake pedal (increased effort)
- Reduced brake assist
- Possible vacuum leak hissing sound
- Engine running rough or stalling
03. Step-by-Step Diagnosis
Step 1: Scan for additional codes and freeze frame data.
Step 2: Visually inspect vacuum pump wiring, connectors, and fuse.
Step 3: Test vacuum pump relay and control circuit with a multimeter.
Step 4: Check vacuum pump operation by applying direct battery power.
Step 5: Verify vacuum lines for leaks or blockages.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. The code indicates a potential loss of vacuum assist, which can significantly increase braking distance and effort, posing a safety risk.
How much does it cost to fix?▼
Repair costs typically range from $150 to $400, depending on the root cause. Replacing a vacuum pump can cost $200-$350, while wiring repairs may be less.