Turbocharger Boost Control Position Sensor "A" Circuit Intermittent

What You Might Notice

• Malfunction Indicator Light (Check Engine) illuminated
• Poor engine performance and reduced power
• Hesitation or sluggish acceleration
• Decreased fuel economy
• Intermittent boost pressure fluctuations

Most Common Causes

1. 1

   Open circuit in sensor wiring

   A break or poor connection in the turbo boost control position sensor (TBCPS) signal wire prevents proper electrical communication. This is the most common cause of intermittent circuit faults.

2. 2

   Short to voltage in sensor circuit

   The sensor signal wire is contacting a positive voltage source, causing intermittent high voltage signals that confuse the engine computer about actual boost pressure.

3. 3

   Short to ground in sensor wiring

   The signal circuit has an intermittent short to ground, causing the sensor signal to drop unexpectedly and preventing accurate boost control.

4. 4

   Faulty turbo boost control position sensor

   The TBCPS sensor itself is failing or has internal intermittent electrical issues, producing unreliable signals to the engine control module.

How to Diagnose It

1. 1

   Check Open circuit in sensor wiring — A break or poor connection in the turbo boost control position sensor (TBCPS) signal wire prevents proper electrical communication. This is the most common cause of intermittent circuit faults.

2. 2

   Check Short to voltage in sensor circuit — The sensor signal wire is contacting a positive voltage source, causing intermittent high voltage signals that confuse the engine computer about actual boost pressure.

3. 3

   Check Short to ground in sensor wiring — The signal circuit has an intermittent short to ground, causing the sensor signal to drop unexpectedly and preventing accurate boost control.

4. 4

   Check Faulty turbo boost control position sensor — The TBCPS sensor itself is failing or has internal intermittent electrical issues, producing unreliable signals to the engine control module.

How to Fix It

1. 1

   Inspect and repair sensor wiring harness

   Visually inspect the TBCPS sensor connector and wiring for corrosion, loose connections, frayed wires, or damaged insulation. Repair any damaged wiring or reconnect loose connectors securely.

2. 2

   Test sensor circuit for voltage faults

   Use a multimeter to test for shorts to voltage or ground in the sensor signal line. Check continuity along the entire wiring path from sensor to engine control module. Repair any shorted or open sections.

3. 3

   Replace turbo boost control position sensor

   If wiring tests pass but the code persists, the TBCPS sensor itself is likely defective and must be replaced. Disconnect the sensor connector and remove the old sensor, then install the new one and reconnect.

   Turbo Boost Control Position Sensor (TBCPS)↗
4. 4

   Check for exhaust backpressure restrictions

   Verify the turbocharger and exhaust system are not restricted by inspecting the turbo inlet and outlet for blockages or carbon buildup, which can cause the boost sensor to read incorrectly.