P0393 high Severity

P0393: Camshaft Position Sensor B Circuit High Input (Bank 2)

May cause rough idle, poor acceleration, stalling, or no-start conditions

Overview

P0393 indicates a high voltage signal detected in the camshaft position sensor B circuit on engine bank 2, often caused by wiring faults, sensor failure, or PCM issues

Common Symptoms

  • Check Engine Light illuminated
  • Rough idle or unstable RPM
  • Engine stalling or hesitation
  • Poor fuel economy
  • Hard or failed starting

Most Common Causes

Faulty camshaft position sensor B high

Sensor can internally short causing high voltage readings

Damaged wiring harness or connectors in sensor circuit high

Open, short to power, or corrosion in harness common

Poor electrical connection at sensor or PCM medium

Loose or corroded terminals can cause erratic voltage

PCM/ECM input stage malfunction medium

Rare, but possible if all wiring and sensor tests are good

Incorrect timing or mechanical issue affecting sensor signal low

Less frequent cause compared with electrical faults

Diagnostic Steps

  1. Confirm code with professional OBD-II scanner and retrieve live data
    Expected: Camshaft B voltage out of range (higher than spec)
    Interpretation: Validates sensor high input condition
  2. Visually inspect camshaft position sensor B wiring and connector
    Expected: No damage, corrosion or loose pins
    Interpretation: Damage suggests wiring repair before further testing
  3. Measure sensor reference and signal voltages with multimeter
    Expected: Signal within manufacturer specified range
    Interpretation: Out-of-range confirms fault in sensor or circuit
  4. Disconnect sensor and test harness continuity to PCM
    Expected: Continuity present, no shorts to power/ground
    Interpretation: Open or short indicates harness repair needed
  5. Replace sensor if wiring is good and re-test
    Expected: Code does not return
    Interpretation: Sensor was cause
  6. If still present, evaluate PCM input circuit or consult dealer tech resources
    Expected: Fault persists through correct wiring and sensor
    Interpretation: Possible PCM fault

Repair Solutions

Replace camshaft position sensor B medium
Estimated Cost: $80 - $300

Depends on vehicle model and sensor accessibility

Repair or replace damaged wiring/connector medium
Estimated Cost: $50 - $300

Scope varies with extent of harness damage

Clean and secure electrical connections easy
Estimated Cost: $10 - $50

Simple fix if corrosion or loose pins found

PCM/ECM reprogram or replacement hard
Estimated Cost: $600 - $1200

Only after ruling out sensor and wiring faults

Common Misdiagnoses

Avoid these common diagnostic mistakes:

  • Replacing camshaft sensor without checking wiring harness
  • Blaming crankshaft sensor incorrectly
  • Assuming battery/starting system faults cause the code

Frequently Asked Questions

What is the definition of the P0393 engine code?

Technically, the P0393 code represents Camshaft Position Sensor B Circuit High Input (Bank 2). It usually points to a fault within the Ignition.

Should I stop driving if I have P0393?

This is a high priority issue. May cause rough idle, poor acceleration, stalling, or no-start conditions

What happens when the P0393 code is active?

The most typical signs are: Check Engine Light illuminated, Rough idle or unstable RPM, Engine stalling or hesitation.

What causes the P0393 code?

This code is frequently triggered by: Faulty camshaft position sensor B, Damaged wiring harness or connectors in sensor circuit, Poor electrical connection at sensor or PCM.

Repair cost breakdown for P0393

It depends on what needs to be fixed. Clean and secure electrical connections repairs are cheaper (~$50), while PCM/ECM reprogram or replacement repairs are on the higher end (~$1200).

What cars are affected by the P0393 code?

Yes, P0393 is a generic code that applies to all OBD-II compliant vehicles, including Ford, Toyota, Honda, Chevrolet, Nissan, Dodge, BMW, and more.

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