AutoCodes – Generic – P0388

P0388 Code - Crankshaft Position Sensor 'B' Circuit High Input

Quick Answer

The Crankshaft position sensor also known as the crank position sensor is an electronic device used in an engine to record the rate at which the crankshaft is spinning. Common causes include Faulty crankshaft position sensor, Crankshaft position sensor harness is open or shorted, Crankshaft position sensor circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P0388 indicates Crankshaft Position Sensor 'B' Circuit High Input.
Common causes: Common causes include Faulty crankshaft position sensor, Crankshaft position sensor harness is open or shorted, Crankshaft position sensor circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 10,015

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jun 14, 2020

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
Comments
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Code P0388 Description

The Crankshaft position sensor also known as the crank position sensor is an electronic device used in an engine to record the rate at which the crankshaft is spinning. This information is used by the Electronic Control Module (ECM) to control ignition and fuel injection. The sensor system consists of a rotating part, typically a disc, as well as a static part, the actual sensor.
When the engine is running, the high and low parts of the teeth cause the gap with the sensor to change. The changing gap causes the magnetic field near the sensor to change. The change in the magnetic field cause the voltage from the sensor to change.

OBDII Code P0388 - Crankshaft Position Sensor 'B' Circuit High Input - AutoCodes.com — P0388 Code - Crankshaft Position Sensor 'B' Circuit High Input

What does this mean?

What are the Possible Causes of the DTC P0388?

Faulty crankshaft position sensor
Crankshaft position sensor harness is open or shorted
Crankshaft position sensor circuit poor electrical connection
Signal plate may be damage
Starter motor may be faulty
Starting system circuit
Dead or weak battery

How to Fix the DTC P0388?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

Sometimes and in some models, low battery voltage or a weak starter can trigger a Crankshaft Position Sensor code. Before replacing any parts, recharge or replaced battery.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0388 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0388 code?

Need more information on how to fix the P0388 code? Get Access to Factory Service Manuals

Need Help with the Code?

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Information for Specific Makes

P0388 Mercedes-Benz — Crankshaft Position Sensor 'B' Circuit High Input

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.