Turbocharger Boost Control Position Sensor "A" Circuit Low
P2564 indicates the turbo boost control position sensor (TBCPS) circuit is reading abnormally low voltage, meaning the sensor signal to the PCM is below the expected range. This prevents proper turbocharger boost pressure regulation and can cause reduced engine performance and fuel economy issues.
What You Might Notice
- Malfunction Indicator Light (Check Engine Light) illuminated
- Poor engine performance and reduced power
- Hesitation or lag during acceleration
- Decreased fuel economy
- Difficulty maintaining consistent boost pressure
Most Common Causes
- 1
Short to ground in signal circuit
The wiring harness from the TBCPS sensor to the PCM has a break or is touching ground, causing the signal voltage to drop below normal operating range.
- 2
Failed TBCPS sensor
The turbo boost control position sensor has internal damage or wear and can no longer produce a proper voltage signal to the engine control module.
- 3
Short to ground in power circuit
The 12V power supply line to the TBCPS sensor is shorted to ground, preventing the sensor from receiving adequate voltage to operate correctly.
- 4
Corroded or loose sensor connector
Poor electrical contact at the sensor connector due to corrosion, moisture, or loose pins reduces signal voltage transmission to the PCM.
How to Diagnose It
- 1
Check Short to ground in signal circuit — The wiring harness from the TBCPS sensor to the PCM has a break or is touching ground, causing the signal voltage to drop below normal operating range.
- 2
Check Failed TBCPS sensor — The turbo boost control position sensor has internal damage or wear and can no longer produce a proper voltage signal to the engine control module.
- 3
Check Short to ground in power circuit — The 12V power supply line to the TBCPS sensor is shorted to ground, preventing the sensor from receiving adequate voltage to operate correctly.
- 4
Check Corroded or loose sensor connector — Poor electrical contact at the sensor connector due to corrosion, moisture, or loose pins reduces signal voltage transmission to the PCM.
How to Fix It
- 1
Inspect and repair wiring harness
Locate the turbo boost control position sensor wiring harness and inspect for cuts, abrasions, or exposed wires touching ground. Repair any damaged insulation with electrical tape or replace the affected wire section. Test continuity and voltage after repair.
- 2
Replace TBCPS sensor
Disconnect the sensor connector, unbolt the sensor from the turbocharger or intake manifold, and install a new turbo boost control position sensor. Reconnect the wiring harness and clear the code to verify the fix.
- 3
Clean or replace sensor connector
Disconnect the TBCPS sensor connector and inspect for corrosion or bent pins. Clean the connector contacts with electrical contact cleaner and a small brush, or replace the connector if pins are damaged. Reconnect and test for proper voltage.
- 4
Check power supply voltage at sensor
Use a multimeter to measure voltage at the sensor power pin with the ignition on. If voltage is below specification (typically 5V), trace the power circuit back to the PCM for breaks, shorts, or failed relay connections.
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