P0393 — Camshaft Position Sensor "B" Circuit High (Bank 2)

OBD2 code P0393 flags a problem with the camshaft position and variable valve timing (camshaft position sensor "B" circuit high (bank 2)). Short, gentle driving to a shop is usually possible. Common culprits: damaged sensor wiring or reluctor ring, worn cam phaser, worn timing chain/belt or jumped timing.

powertrain (engine/transmission)

Is it safe to drive?

Usable only if the engine runs steadily P0393 can cause the ECU to lose Bank 2 camshaft synchronization, making starting, power delivery, and valve timing less predictable. If the engine runs smoothly, avoid hard acceleration and schedule repair promptly; if it stalls, runs severely rough, or loses power, stop driving and have the vehicle repaired or towed.

Typical symptoms

The check-engine light illuminates with P0393 stored in the powertrain controller
Rough idle, hesitation, or a noticeable loss of engine power
Difficult starting, extended cranking, or a crank-without-start condition
Unstable idle or intermittent stalling when Bank 2 camshaft synchronization is lost
Erratic variable valve timing operation or unusual engine noise
A P0393-related code may return immediately after the code is cleared

Common causes

A failed camshaft position sensor B on Bank 2 with an output stuck high or an internal circuit failure
A short circuit from the Bank 2 camshaft position sensor B signal wire to 5 V reference or battery voltage
Damaged or open wiring that allows the sensor signal to float or be pulled to a high voltage
Corrosion, oil contamination, or a backed-out terminal in the sensor connector
A poor sensor ground or defective sensor reference circuit in the wiring harness or ECU
Incorrect connector pin arrangement or improper wiring after a previous repair

How to diagnose with an OBD scanner

Confirm the code and related data Connect an OBD2 scanner or ELM327 adapter and read stored, pending, and permanent trouble codes. Confirm P0393, review freeze-frame engine speed and load, and check for related Bank 2 camshaft synchronization or sensor-reference codes before clearing anything.
Inspect the Bank 2 sensor and harness Use the vehicle wiring diagram to locate camshaft position sensor B on Bank 2. Inspect its connector and wiring for oil intrusion, corrosion, chafing, heat damage, bent pins, and terminals that are loose or pushed back. Do not assume that sensor B is always the intake or exhaust sensor.
Perform guided electrical tests Disconnect the sensor and follow the manufacturer procedure for checking the signal wire for a short to power or ground. Test the reference voltage, sensor ground, and connector pin integrity at the harness. A high signal reading can result from a short to voltage, a floating circuit, or an internally failed sensor.
Observe the live sensor signal Back-probe the Bank 2 sensor B signal while the engine starts and runs. With a scope-capable ELM327 tool or oscilloscope, confirm that the waveform has the correct amplitude, pulse spacing, and no missing transitions. A steady high voltage or irregular waveform supports a wiring or sensor fault.
Repair and verify If the wiring and connector tests pass, replace sensor B on Bank 2 with the correct application-specific part. Repair damaged circuits or terminals as needed, clear P0393 with an OBD2 scanner, and confirm that the code does not return while the engine is cold and at operating temperature.
Road-test the repair Verify smooth idle, normal throttle response, proper starting, and stable variable valve timing operation. Recheck for P0393 and related codes after the road test because an intermittent connector or harness fault may not appear during static inspection.

Approximate repair cost

A typical independent-shop estimate for P0393 is about $150-$500 total, including roughly $80-$250 for the Bank 2 camshaft position sensor and $120-$300 for diagnosis and labor. Harness or connector repairs can add to the total. These figures are estimates and vary by region.

Common questions

What does P0393 specifically identify?

P0393 identifies a high-voltage condition in the camshaft position sensor B circuit on Bank 2, not a general camshaft or engine-control failure.

Does P0393 always mean the camshaft sensor is defective?

No. A short to voltage, floating or damaged wiring, poor ground, connector corrosion, or an ECU reference-circuit problem can also create the high-signal condition.

Can the vehicle still be driven with P0393?

It may drive if the engine runs smoothly, but rough operation, stalling, poor starting, or unstable valve timing is possible. Repair should be scheduled promptly if symptoms are present.

Will clearing P0393 repair the fault?

Clearing the code only resets the controller's stored information. P0393 will generally return if the high sensor voltage, wiring defect, or failed sensor remains.

When your check engine light illuminates and a scan tool pulls code P0393, the powertrain control module has detected that the camshaft position sensor signal for Bank 2 is reporting a voltage that exceeds the upper acceptable limit. The formal definition reads "Camshaft Position Sensor 'B' Circuit High (Bank 2)", and this falls under the powertrain category since it directly affects engine operation and timing control.

Bank 2 refers to the engine bank that does not contain cylinder number one. On V-type engines, this is the opposite side from cylinder 1. If you own an inline-four or inline-six, "Bank 2" still identifies the exhaust-side camshaft in many diagnostic conventions. Locating the correct sensor before testing or replacement prevents wasted parts and labor.

To set P0393, the PCM compares the live camshaft position signal against its internal reference values. If the voltage stays above the maximum threshold for longer than the calibrated period—typically across multiple drive cycles—the module logs the fault and captures a freeze frame snapshot. That snapshot records RPM, engine load, coolant temperature, and vehicle speed at the exact moment the problem occurred. Reviewing this data first often points directly toward the root cause rather than chasing symptoms.

Common Symptoms

Hard starting or unusually long cranking before the engine fires
Rough idle and noticeably weak low-end torque
Higher fuel consumption than usual during normal driving
Illuminated Check Engine lamp
Reduced engine power, especially under acceleration
In some cases, the engine may enter a failsafe (limp) mode with severely limited RPM and throttle response

Common Causes

The most frequent culprits behind P0393 tend to appear in order of likelihood:

Faulty camshaft position sensor on Bank 2
Low engine oil level or oil contamination that disrupts VVT hydraulic operation
Stuck or clogged VVT (variable valve timing) oil control valve
Damaged wiring harness or corroded connectors affecting the sensor circuit
Worn or stretched timing chain, or jumped timing belt alignment
Bent or damaged reluctor ring on the camshaft
Failed PCM (rare, but possible if all other components test good)

How to Diagnose P0393

Working through this code methodically saves both time and money. Follow these steps before buying any parts:

Connect an OBD2 scanner and confirm that P0393 is stored. Record the freeze frame data—it reveals engine conditions (temperature, load, RPM) when the fault was detected. This snapshot often reproduces the exact circumstances needed to trigger the code on a retest.
Check for related diagnostic trouble codes. Secondary codes such as P0300 (random misfire) or P0340 (camshaft position sensor circuit malfunction) can point toward a shared cause. Also search for manufacturer TSBs specific to your make, model, and year—many P0xxx codes have documented software patches or known fixes.
Inspect the wiring and connectors at the Bank 2 camshaft position sensor. Look for frayed insulation, broken wires near the connector, corrosion on the pins, or evidence of heat damage. A poor ground or an open circuit will force the signal voltage high.
Verify engine oil level and condition. VVT systems rely on oil pressure to actuate phasers and solenoid valves. If the oil is dark, sludgy, or below the dipstick mark, address this before anything else. Dirty oil can jam the OCV and produce false cam position readings.
Monitor live data while the engine runs. Compare the commanded cam timing versus the actual position reading. A large discrepancy between target and actual indicates either a mechanical timing issue or a failing sensor.
Clear the code and complete a drive cycle that mirrors the freeze frame conditions. If P0393 does not return, the issue may have been intermittent. If it recurs, focus testing on the sensor and its circuit.

Repair Options

Once diagnosis identifies the failed component, repair paths diverge significantly in cost:

Replace the camshaft position sensor (Bank 2): $120–$350
Replace the VVT oil control valve (OCV): $200–$500
Timing chain or belt repair (including jumped timing correction): $800–$2,500

Always start with the least expensive likely cause. The camshaft position sensor itself is the most common failure point and costs the least to replace. VVT solenoid issues appear second in frequency. Mechanical timing problems are less common but far more expensive to correct.

Cost to Fix P0393

Total repair costs for P0393 depend almost entirely on which part is actually faulty. At independent shop rates in the United States, expect the following ranges for parts and labor combined:

Sensor replacement: $120–$350
OCV replacement: $200–$500
Timing chain or belt repair: $800–$2,500

Overall, fixing P0393 typically falls between $120 and $2,500 depending on root cause. A proper diagnosis before purchasing parts is strongly advised—the most expensive scenario is rarely where you should start. Many shops will diagnose this code for a flat fee or hour rate before committing to any repair.

Can You Drive with P0393?

Drive with caution. While the engine may continue running, performance will likely suffer. Some vehicles reduce power output and limit RPM when this code is active. If the timing has jumped due to a broken chain or slipped belt, continued operation on an interference engine risks contact between valves and pistons—a catastrophic failure requiring a full engine teardown or replacement. Diagnose and repair P0393 before any long trip or highway driving.