P0393 Code: Camshaft Sensor B Circuit High, Bank 2

What Does the P0393 Code Mean?

P0393 concerns the camshaft electrical input designated B on Bank 2. Camshaft-position information supports engine synchronization; this code does not by itself establish incorrect mechanical timing or an oil-control actuator fault.

Bank 2 does not contain cylinder 1. Verify its physical side and the manufacturer mapping of sensor B through current engine information. Similar-looking sensors and generic photographs do not establish component identity.

A digital input normally switches between electrical states. A valid high portion of a waveform differs from an input remaining high when a changing signal is expected. Sensor technology and monitor prerequisites determine the interpretation.

P0393 Symptoms, Severity, and Driving Safety

Diagnose promptly; repeated stalls, severe misfire or unsafe starting problems require stopping

P0393 Causes and the Evidence That Separates Them

These six branches describe electrical evidence to investigate, not ranked failure rates. Several can produce a similar high input. Identify the sensor technology and circuit support before deciding whether the problem is a powered short, an open path, a connector or the sensor electronics.

A high-circuit fault can occur intermittently. Preserve its operating conditions and recent work; a brief successful stationary check does not exclude poor contact or lost support.

Using MA200 Plus During P0393 Diagnosis

The iCARZONE MA200 Plus can retrieve supported engine fault records, event data and available camshaft or synchronization parameters on a covered vehicle. Save the full report and companion codes before unplugging components or clearing the evidence.

Check coverage for the actual engine and ECU. General engine access does not guarantee a named Bank 2 B parameter, synchronization status or every manufacturer-specific test. Confirm the required function rather than assuming that all camshaft information is available.

A scanner displays controller-reported information. It does not independently measure the physical camshaft waveform, terminal contact quality or circuit voltage drop. Those checks require appropriate electrical equipment, connector information and safe access to the correct signal route.

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No reset or active test repairs a damaged sensor wire. Do not promise P0393-specific actuator testing, ECU flashing or a required relearn from the product name alone. After the proven repair, perform only the supported setup and monitor verification required by the exact manufacturer procedure.

How to Diagnose P0393 in 6 Steps

Use these six stages with the actual engine wiring and monitor procedure. Connector pin numbers, sensor voltages, waveform limits and crank-event counts are not universal. Avoid a parts-swap diagnosis or a test that can damage the circuit.

P0393 Quick Diagnostic Path

• 1

  Save the full code and operating record

  • Save P0393, its OEM wording, status, freeze frame and companion faults. Record starting symptoms, sensor replacement and nearby work.
  • Preserve this information before clearing codes or disconnecting components. A fault seen during cranking may need a different safe observation method from one that appears after warming.
• 2

  Confirm Bank 2 sensor B and the actual architecture

  • Identify cylinder numbering, the correct camshaft sensor, connector face and receiving-controller terminal using current vehicle information. Determine the required supply and signal technology.
  • Do not transfer Bank 1 A pinouts. Resolve inconsistent labels through the actual OEM circuit and component mapping.
• 3

  Inspect connections and prove electrical support

  • With the system in its prescribed safe state, inspect retention, contamination, damaged insulation, routing and recently disturbed areas. Check the specified supply and return through approved methods.
  • Use appropriate probes and measurement loading. Continuity alone does not prove a powered connection; oversized probes can damage terminal contact.
• 4

  Observe the signal under valid operating conditions

  • Use suitable equipment to compare the sensor signal with the expected behavior when the engine is safely turning. Verify whether high is persistent or the observed portion of normal switching.
  • A basic meter may average a waveform. Use the specified method and conditions, not one stationary reading or a generic resistance test.
• 5

  Separate the sensor, harness and receiving input

  • Compare suitable measurement points at the sensor and controller. Perform only the approved disconnection or isolation checks to distinguish loss of support, an open route, cross-circuit voltage or component failure.
  • Account for normal pull-up behavior before interpreting a high unplugged input. Prove external wiring, terminals and support before considering an ECU fault or an applicable software procedure.
• 6

  Repair the proven branch and verify safe operation

  • Repair the proven connector, wiring, support or sensor fault correctly. Restore seals and secure routing away from heat and moving parts.
  • Complete required setup, recheck the actual signal and run the relevant monitor safely. Compare current and pending records with the original event; an erased warning alone does not prove reliable starting or a repaired circuit.

How to Fix P0393 and Verify the Repair

Request an evidence-based estimate separating diagnosis, parts and verification. Accessible connector work and difficult harness repair differ substantially; P0393 alone does not justify a timing-system replacement package or a universal price.

For recurrence, compare the original event and signal route. Recheck intermittent contact, support and part compatibility before further replacement. Assess mechanical noise and separate timing-correlation faults on their own evidence.

P0393 OEM Differences and DIY Limits

The Audi A8/A8L/S8 March 2013 reference book identifies P0393 as Bank 2 camshaft sensor B circuit high. Its example monitors distinguish a persistently high signal during crankshaft activity from the adjacent low and pattern-performance categories.

The engine sections use different monitoring counts. Those values are not universal test limits and are not transferred here. Confirm current engine-specific wiring, sensor identity and safe test conditions; a historical monitor table does not authorize a sensor, ECU or timing-chain replacement.

Related Camshaft, Signal and Electrical-Support Guides

Compare the sensor letter, bank and monitor type before using another code guide. Electrical-low, intermittent, performance and internal RPM records require different evidence; a shared symptom does not make their sensors or repairs interchangeable.

For other stored faults, use the iCARZONE OBD-II fault-code center.

Frequently Asked Questions About P0393

Sources and Technical Review Notes

• Autel published DTC reference glossary — Confirms the Bank 2 sensor B circuit-high description and adjacent code categories.
• Audi A8/A8L/S8 reference book, March 2013 — Scoped examples of electrical-high camshaft monitoring with engine-specific criteria.

iCARZONE

Technical sources checked September 8, 2026. This is a source-based diagnostic guide, not a report of a hands-on vehicle repair. Confirm bank and sensor mapping, sensor technology, connector views, supply and return architecture, pull-up behavior, waveform requirements and safe engine-operation limits for the exact vehicle.