Crankshaft Position Sensor B Circuit High
The P0388 code means the vehicle's onboard diagnostic system has detected: Crankshaft Position Sensor B Circuit High. This is a critical severity code.
- Keep driving?
- No — stop driving
- DIY difficulty
- moderate
- Estimated cost
- $80 - $400 (parts and labor)
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What Are the Symptoms of P0388?
- Check Engine Light on
- Engine may not start
- Stalling
- No signal from sensor B
What Causes P0388? (Most Likely First)
- Open circuit in crank sensor B wiring Very High
- Failed sensor (open) High
- Disconnected connector Moderate
- PCM input open Low
Can I Still Drive with P0388?
No — stop driving. P0388 is rated critical severity. Continuing to drive in this state risks further damage — get it looked at before your next trip.
Frequently Asked Questions
What does circuit high mean on crank sensor B?
An open circuit or disconnected sensor causes the signal voltage to float high.
Can I just use sensor A?
Some engines can run on one crank sensor in degraded mode, but it is not reliable for long-term operation.
How long does crank sensor replacement take?
Typically 30-60 minutes for sensor replacement, depending on accessibility.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose P0388?
-
Check connector is seated.
-
Measure sensor resistance.
-
Test wiring continuity.
-
Replace sensor if wiring is intact.
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
- Cross-checked against the SAE J2012:2002 DTC table (2026-08-27)archived scan of the SAE standard — readable copy, not SAE’s current edition
Which Vehicles Commonly Get P0388?
- 2010-2020 Ram 3500 (6.7L Cummins)
- 2012-2019 Ford F-350 (6.7L Diesel)
- 2008-2018 GMC Sierra 3500 (6.6L Duramax)
- 2011-2020 Chevrolet Silverado 3500 (6.6L Duramax)
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