P0238 on the 6.0L Power Stroke is a turbocharger boost sensor A circuit high input fault. The 6.0L uses a boost, or manifold absolute pressure, sensor to report intake pressure to the PCM for fueling, variable geometry turbo control, and smoke management. P0238 sets when the PCM reads a boost sensor voltage too high, indicating a short to voltage, a lost ground, or a failed sensor.
On the 6.0L the boost sensor lives in a hot, sooty environment and can foul or fail over time. A high reading confuses the PCM's fueling and turbo strategy and can trigger reduced power. Because P0238 is an electrical circuit code, the fix usually centers on the sensor, its wiring, and the connector rather than the turbo, so verify the circuit before condemning expensive hardware.
What P0238 means
The boost sensor outputs a voltage that rises with intake pressure. P0238 sets when that voltage stays at the high end of the scale, indicating a signal wire shorted to the reference or to voltage, a lost ground allowing the signal to float high, or a sensor that has failed high. The PCM cannot trust the boost reading and may derate power.
Common causes
- Signal wire shorted to reference or battery voltage
- Open or high-resistance sensor ground
- Corroded or loose boost sensor connector
- Soot-fouled or failed boost sensor
- Chafed harness bridging signal and reference
Symptoms
- Reduced power or limp mode
- Check engine light with P0238 stored
- Black smoke or poor economy from skewed fueling
- Boost gauge reading that does not match performance
- Companion boost or turbo codes
How to diagnose it
With a scan tool, view the boost sensor value key on, engine off; it should read close to barometric pressure. A value pinned high at rest confirms the fault. Inspect the sensor connector for corrosion and a secure fit, and back-probe to confirm a clean ground, since a lost ground is a common cause of a high reading. Check the signal wire for a short to the reference or to voltage, and confirm continuity to the PCM. Remove and inspect the sensor tip for soot fouling.
How to fix it
Restore a poor ground and repair any wiring shorted to voltage or reference first, then clean or replace a corroded connector. Clean a soot-fouled sensor or replace it if the element is damaged. If the wiring checks good but the signal stays high, replace the boost sensor. After the repair, clear the code, confirm the sensor reads barometric pressure at key on and boost tracks correctly under load, and road test. For the correct boost sensor for your 6.0L Power Stroke, contact sales@coredieselparts.com.
Frequently asked questions
Can a dirty sensor cause P0238?
Yes. Soot can foul the boost sensor and skew its reading. Inspect and clean the tip, but if the element is damaged, replace the sensor.
Is P0238 the sensor or the wiring?
Both are possible. Confirm a clean ground and check for a short to voltage. If the wiring is good and the signal stays high, replace the sensor.
Will P0238 hurt fuel economy?
It can. A false boost reading skews fueling, which shows up as black smoke and reduced mileage until the sensor or wiring is corrected.
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