P0388 OBD-II Trouble Code: Crankshaft Position Sensor B Circuit High Input

Our certified mechanics come to you · Get a fair and transparent estimate upfront


Cost of diagnosing the P0388 code

P0388 is a diagnostic trouble code (DTC) for "Crankshaft Position Sensor B Circuit High Input". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic for $154.99 . Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $50.0 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate* Credit towards follow-up repair Earliest Availability
Ford $154.99 $50.0
Toyota $154.99 $50.0
BMW $164.99 $50.0

*Estimates may vary by market

SCHEDULE P0388 DIAGNOSTIC Get a fair and transparent estimate upfront

P0388 code definition

The P0388 code signifies that there has been a higher than allowed voltage signal from the crankshaft position sensor detected by the car’s computer.

What the P0388 code means

If the crankshaft position sensor sends a higher than allowed voltage signal, the car’s computer will store code P0388. The signal will be about 10% higher than the automaker’s specifications. The Check Engine light will also turn on. However, depending on the vehicle in question, the code may need to be stored up to three times before the Check Engine light turns on to warn the driver of a problem.

What causes the P0388 code?

Several potential causes exist for the P0388 code. These include the following:

  • Damage to the CPS connector
  • Damage to the crankshaft position sensor itself
  • Wiring deterioration due to exposure to engine oil leaks
  • Missing teeth or damaged reductor ring
  • Broken timing belt that damages CPS components

What are the symptoms of the P0388 code?

Symptoms of the P0388 code vary from one situation to another, and from vehicle to vehicle, but they can include the following:

How does a mechanic diagnose the P0388 code?

The first step to diagnose the problem is to connect an OBD II scanner to the car’s computer and read all codes stored. Once this is done, the codes can be cleared and the vehicle test driven to verify the symptoms and determine if the code will reset.

The mechanic should also watch the RPM gauge during cranking and engine operation to determine if it is accurate, or not working. Connecting a scanner can also allow the mechanic to view the RPM signal from the sensor independent of the RPM gauge or when there is no RPM gauge in the vehicle.

The CPS can also be tested directly for reference voltage (outside the vehicle). If it fails, the sensor must be replaced. If the sensor passes, then the problemm is in the wires, wiring harness or connectors. A full visual inspection of all components must be conducted, and any damage must be repaired. The teeth or reductor ring should also be inspected for damage, and replaced if any is noticed.

Once the problem has been repaired, the codes must be cleared again, and the vehicle test driven once more. Note that it may require more than one test drive to set a code.

Common mistakes when diagnosing the P0388 code

One of the more common mistakes here is not inspecting the wiring, wiring harness and connectors prior to replacing the crankshaft position sensor.

How serious is the P0388 code?

The P0388 code is serious, as it has a direct impact on whether the vehicle can be driven. Because this problem can lead to no start situations, it could leave you stranded. Have the problem diagnosed and repaired as soon as possible.

What repairs can fix the P0388 code?

Generally, the most common repair is replacing a damaged or failed crankshaft position sensor. However, wiring problems, corrosion and connector problems are also very common, and must be ruled out before replacing any parts.

Additional comments for consideration regarding the P0388 code

A full diagnosis must be completed to determine the actual cause of the P0388 code. Electrical problems are just as common as failed parts in this situation.

Need help with a P0388 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

Check Engine Light
trouble codes
P0388

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P0388 code.

SCHEDULE P0388 DIAGNOSTIC
Get a $50 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating

(8600)

Rating Summary
8017
273
65
46
199
8017
273
65
46
199
 at YourMechanic

Brandon

9 years of experience
133 reviews
Brandon
9 years of experience
Ford Escort L4-2.0L - Check Engine Light is on - Nashville, Tennessee
Brandon showed up ahead of schedule, was very personable and diagnosed my problems. He also scheduled my next appointments which will be with him.
 at YourMechanic

William

23 years of experience
33 reviews
William
23 years of experience
Lexus IS250 V6-2.5L - Check Engine Light is on - Mableton, Georgia
Arrived early which was great. William was courteous, and attentive to the issue. Even though it took several attempts I'm so happy he was determined to fix it and he did!
 at YourMechanic

Dan

40 years of experience
1080 reviews
Dan
40 years of experience
Plymouth Grand Voyager - Check Engine Light is on - Lawrenceville, Georgia
Mr. Dan Barber was quite patient, courteous and quite knowledgeable. From my observation, Mr. Barber appears to be quite professional.
 at YourMechanic

Christopher

9 years of experience
120 reviews
Christopher
9 years of experience
Ford Fiesta L4-1.6L - Check Engine Light is on - Smyrna, Georgia
Chris communicated with us each step of the way up until his arrival. He listened well, was knowledgeable, and was prepared. He took the time to diagnose the problem, explained the what, why and how and provided a solution. I would definitely recommend him and will use him again.


More related articles

P2563 OBD-II Trouble Code: Turbocharger Boost Control Position Sensor Circuit Range/Performance
P2563 code definition Turbocharger Boost Control Position Sensor Circuit Range/Performance What the P2563 code means P2563 is an OBD-II generic code. The...
P2441 OBD-II Trouble Code: Secondary Air Injection System Switching Valve Stuck Closed Bank 1
P2441 P2441 code definition Secondary Air Injection System Switching Valve Stuck Closed Bank 1 What the P2441 code means P2441 is an OBD-II code for the engine control module (ECM) detecting no exhaust pulse while monitoring the exhaust pressure sensor...
P0422 OBD-II Trouble Code: Main Catalyst Efficiency Below Threshold
P0422 means the catalytic converter is malfunctioning. Other causes may be oxygen sensors, fuel pressure regulator or a mass air flow sensor.

Related questions

Check Engine Light illuminated in car.
The Check Engine Light coming on is to alert the driver that the engine or powertrain is having a problem that it has detected. The light could be something simple like the gas cap was left loose to the engine...
Engine light on windshield wiper does not work
Hi there - check fuses for the windshield wiper issue, that is the most likely problem with that component. If the fuse is good, the switch is the next likely component issue. I would recommend having an electrical components are...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com