Turbocharger/Supercharger Boost Sensor A Circuit Malfunction

What it means

The engine computer has detected an electrical fault in the circuit of boost pressure sensor A, which measures the pressure produced by the turbocharger or supercharger. Without a reliable reading the computer cannot control boost safely, so it usually limits power.

Related codes: P0236P0237P0238P0234P0299

Symptoms4

• Check engine light on.
• Noticeable loss of power or limp mode.
• Slow acceleration with no feeling of boost.
• Sometimes higher fuel consumption.

Possible causes5

• Corroded, loose or oil-contaminated boost sensor connector.
• Open or shorted wire in the sensor circuit.
• Failed sensor.
• Fault in a reference voltage shared with other sensors.
• Engine computer fault (rare).

How to diagnose5

1. Read the boost pressure value on a scan tool with the engine off and ignition on, and compare it with barometric pressure.
2. Visually inspect the connector and wiring for corrosion, oil or chafing.
3. Measure the reference voltage, ground and signal at the sensor connector and compare them with the manufacturer specification.
4. Wiggle the wiring while watching the reading to catch an intermittent open.
5. Check for shared reference voltage codes such as P0641.

How to fix5

1. Clean or replace the connector and reseat it.
2. Repair damaged wiring in the sensor circuit.
3. Replace the boost pressure sensor if it is proven faulty.
4. Fix the reference voltage fault if it is shared with other sensors.
5. Clear the codes, then test under load and confirm the code does not return.

Repair cost

In Saudi riyals; the highlighted part is the expected range for this fault.

The cost is low for a connector or wire repair and reaches the upper end when the boost sensor is replaced; its price varies by vehicle.

Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026

Frequently asked questions