What does it mean?
The module supplies the turbocharger outlet pressure sensor with a reference voltage and expects a signal that rises and falls with the pressure after the compressor. This code is stored when the signal stays above the highest voltage a working sensor can produce, near reference level, for the calibrated time. An open signal wire or an open sensor ground allows the module input to float up through its internal pull-up, so a broken connection produces the same symptom as a short to a voltage feed. Without believable boost feedback the module cannot close the boost control loop and normally holds the engine at a reduced power level.
Symptoms
- MIL on with a clear loss of power under load
- Boost pressure value on a scan tool stuck at the top of the scale even with the engine off
- limp mode on many vehicles as the module protects the engine from an assumed overboost
- Very poor acceleration and no charge pressure build up
- Black smoke or uneven running on diesels
- Turbocharger sounding unusually quiet because the control defaults to minimum boost
Likely causes
- Open circuit in the signal wire between the sensor and the control module
- Open or high resistance sensor ground circuit
- Signal wire shorted to a battery voltage feed in the same harness bundle
- Connector not locked home, or a terminal that has backed out of the housing
- Internally open pressure sensor element
- Corroded pins creating a resistance so high the circuit behaves as an open
- Rarely, an internal control module fault holding the input at reference
How to fix it
- Confirm the value live with the key on and engine off; a healthy sensor reads atmospheric pressure, not full scale
- Jump the signal terminal to ground at the sensor connector; if the displayed pressure drops to the low limit, the harness and module are fine and the sensor is at fault
- Measure continuity and voltage drop on the sensor ground circuit back to its ground point
- Check signal wire continuity from the sensor connector to the module, flexing the harness during the test
- With the sensor unplugged, look for battery voltage on the signal wire to identify a short to power
- Repair the open or shorted conductor, renew damaged terminals and reseat the connector properly
- Replace the sensor once the wiring proves good and the element itself is open