Turbo/Super Charger Boost Sensor "A" Circuit High
The MAXXFORCE-P0238 (MaxxForce) diesel fault code means: Turbo/Super Charger Boost Sensor "A" Circuit High. This is a serious severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- intermediate
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What Are the Symptoms of MAXXFORCE-P0238?
- Check Engine light
- Reduced power (the module may substitute a default boost value)
What Causes MAXXFORCE-P0238? (Most Likely First)
- Boost sensor signal wire shorted to voltage, or an open ground High
- Failed boost pressure sensor High
- Damaged or corroded connector Medium
Can I Still Drive with MAXXFORCE-P0238?
Yes, but fix soon. MAXXFORCE-P0238 is rated serious severity. It is not an immediate stop-driving fault, but it will not clear itself — book the repair rather than ignoring it.
Frequently Asked Questions
What does P0238 mean on a MaxxForce?
P0238 means Turbo/Super Charger Boost Sensor "A" Circuit High. The boost pressure sensor "A" signal is above the range the control module expects.
Is P0238 a MaxxForce-specific code?
No. P0238 is a generic OBD-II code defined by SAE J2012, so it means the same thing on any vehicle that sets it. The exact conditions Navistar uses to set it on its diesels are in Navistar service information.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose MAXXFORCE-P0238?
Check the sensor signal on a scan tool with the key on, engine off; it should match barometric pressure.
Check the sensor ground circuit and look for a short to voltage on the signal wire.
Inspect the connector and harness for damage or corrosion.
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- California Code of Regulations, Title 13 section 1971.1 (Heavy-Duty OBD)malfunction criteria, section (e)
- SAE J2012Diagnostic Trouble Code Definitions (defines P0238 as a generic OBD-II code)
P0238 on Other Platforms
The same code ID appears across other engines, vehicles, and equipment. Diagnostic flow varies by platform — see the matching breakdown:
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