P0368 Camshaft Position Sensor "B" Circuit High Input (Bank 1)

P0368 means the engine control module has detected an abnormally high electrical signal from the Camshaft Position Sensor “B” circuit on Bank 1.

The important words here are “Circuit High Input.” This does not mean the camshaft is physically turning too fast, the engine RPM is too high, or the camshaft timing is necessarily advanced.

The ECM is seeing a voltage or electrical condition on the monitored Camshaft Position Sensor B circuit that is higher than the expected range.

The exact sensor represented by “B” is manufacturer-specific. On many engines it refers to a particular camshaft sensor, often associated with the exhaust camshaft on a dual-cam engine, but this is not universal. Bank 1 generally refers to the cylinder bank containing cylinder #1.

What Does “Circuit High” Mean?

A camshaft position sensor produces a signal that the ECM uses to determine camshaft position and rotation.

When the ECM sets P0368, it has detected that the electrical signal is staying or behaving at a level that is too high compared with its expected range.

Possible electrical causes include:

• Signal wire shorted to battery voltage

• Incorrect sensor supply voltage

• Faulty camshaft position sensor

• Damaged wiring

• Poor connector connection

• Incorrect sensor installation

• Internal sensor failure

• Signal circuit resistance or abnormal electrical conditions

• Incorrect replacement sensor

• ECM input circuit fault

The code therefore points primarily toward the electrical signal circuit, rather than immediately indicating a mechanical camshaft timing problem.

What Does Camshaft Position Sensor “B” Do?

The camshaft position sensor tells the ECM where the camshaft is in relation to engine rotation.

This information allows the ECM to coordinate engine operation with much greater precision.

Depending on the engine, the signal can be used for:

• Fuel injection timing

• Ignition timing

• Cylinder identification

• Variable valve timing control

• Camshaft position monitoring

• Crankshaft/camshaft synchronization

• Misfire detection

• Engine starting strategy

On some engines, the ECM can continue operating using the crankshaft signal and another camshaft signal if one cam sensor fails. On others, a camshaft signal problem can cause severe starting and running problems.

Symptoms of P0368

The symptoms vary depending on the engine and how critical Camshaft Sensor B is to the control strategy.

Possible symptoms include:

• Check Engine Light

• Hard starting

• Long cranking

• Intermittent no-start

• Rough idle

• Engine hesitation

• Misfires

• Poor acceleration

• Reduced engine performance

• Engine stalling

• Increased fuel consumption

• Poor operation of variable valve timing

Some vehicles may continue to drive almost normally while the fault is present, particularly if the ECM has another usable timing signal.

Common Causes of P0368

Signal wire shorted to voltage

This is one of the most important possibilities with a circuit-high code.

If the sensor signal wire contacts a battery-voltage circuit or another voltage source, the ECM may see a continuously high signal.

A damaged wiring harness can create this condition without any obvious visible damage.

Faulty camshaft position sensor

The sensor's internal electronics can fail and produce an abnormally high output.

This can happen suddenly or intermittently.

Incorrect sensor power supply

If the sensor uses a regulated supply, an abnormal supply voltage can affect its output.

The supply should be measured against the manufacturer's specification rather than assuming that every camshaft sensor uses the same voltage.

Poor ground

A sensor with an unstable or poor ground can produce an incorrect output.

A ground problem can sometimes cause several sensor codes simultaneously if multiple sensors share a common ground circuit.

Damaged connector or terminals

Corrosion, water intrusion, loose terminals or poor terminal tension can alter the electrical characteristics of the circuit.

A connector does not have to look badly damaged to cause a high-input fault.

Incorrect replacement sensor

A sensor that physically fits the engine is not necessarily electrically compatible.

Different sensors can use different signal strategies, supply requirements or output characteristics.

Installing the wrong part can therefore create a circuit-high code even though the new sensor is technically functioning.

Wiring resistance or harness damage

Although P0368 is specifically a high-input code, wiring problems can affect the signal in several ways.

The entire circuit should be tested rather than looking only for a short to battery voltage.

ECM fault

An internal ECM input problem is possible, but it is normally a last-stage diagnosis.

The sensor and circuit should be thoroughly tested before condemning the ECM.

How P0368 Should Be Diagnosed

Start by scanning all engine-control codes, including pending codes.

Pay particular attention to other camshaft, crankshaft, synchronization and VVT-related codes.

Then identify exactly which physical sensor is designated Camshaft Position Sensor B, Bank 1 for that engine.

Do not assume that “B” always means the same sensor on every vehicle.

After identifying the correct circuit, inspect the sensor and harness.

Look for:

• Melted insulation

• Chafed wiring

• Broken wires

• Oil contamination

• Water intrusion

• Corroded terminals

• Loose terminals

• Poor connector locking

• Wiring touching hot components

• Incorrect harness routing

Check the Sensor Supply and Ground

The next step is to verify the sensor's electrical requirements.

Depending on the sensor design, there may be:

• Power supply

• Ground

• Signal

A Hall-effect camshaft sensor commonly uses an external power supply, ground and signal circuit.

A variable-reluctance sensor works differently and generates its own AC-type signal.

Because sensor designs vary, there is no universal voltage or resistance value that can be applied to every P0368 diagnosis.

The manufacturer's wiring diagram and specifications should be followed.

Check the Signal Wire for a Short to Voltage

With a circuit-high code, the signal wire deserves particular attention.

The technician should determine whether the signal circuit is unintentionally connected to:

• Battery voltage

• Ignition voltage

• Another sensor supply

• Another signal circuit

A wiring diagram is extremely useful here.

If the signal is stuck high because of an external voltage source, replacing the sensor will not repair the problem.

Use an Oscilloscope When Necessary

A multimeter can establish whether voltage is present, but it cannot always show whether the camshaft signal has the correct waveform.

An oscilloscope can show:

• Signal amplitude

• Pulse shape

• Pulse frequency

• Signal transitions

• A signal stuck high

• Intermittent dropouts

• Electrical noise

• Camshaft signal synchronization

This is especially useful when the code is intermittent or when the sensor passes a basic voltage test.

If the signal is already abnormally high directly at the sensor, the sensor itself or its supply/ground becomes more suspicious.

If the sensor produces a correct waveform but the ECM sees a high signal, the wiring or connector between the sensor and ECM needs closer attention.

What About the Timing Chain?

A timing-chain problem can affect camshaft position, but P0368 does not automatically mean the timing chain is stretched or has jumped.

P0368 specifically identifies a high electrical input condition.

A mechanical timing problem is more likely to be considered when there are additional indications such as:

• Cam/crank correlation codes

• Incorrect synchronization

• Abnormal camshaft timing data

• Timing-related VVT codes

• Unusual mechanical noise

• An abnormal relationship between camshaft and crankshaft waveforms

If the electrical signal is simply stuck high, mechanical timing is not the first place to look.

Could a VVT Problem Cause P0368?

Variable valve timing can certainly create camshaft position-related problems, but it does not normally explain a direct circuit-high electrical fault by itself.

For example, an oil-control problem may cause the camshaft to reach an incorrect position. The ECM can then detect a camshaft timing or correlation problem.

That is different from the sensor signal itself being electrically too high.

Therefore, a VVT actuator or oil-pressure problem should not be used as the first explanation for P0368 unless the electrical circuit has been verified and the diagnostic data points toward a mechanical/VVT issue.

P0368 vs P0367

These two codes describe opposite electrical conditions.

P0367 – Camshaft Position Sensor B Circuit Low Input (Bank 1)

The ECM detects a signal that is lower than expected.

P0368 – Camshaft Position Sensor B Circuit High Input (Bank 1)

The ECM detects a signal that is higher than expected.

A high-input condition can make a short-to-voltage particularly suspicious, while a low-input condition often directs attention toward a short to ground or a missing/weak signal.

However, the sensor itself can also produce either type of fault depending on its internal failure.

P0368 vs P0369

P0368 indicates a high electrical input.

P0369 indicates an intermittent signal.

An intermittent wiring connection can sometimes cause different codes depending on how the ECM sees the signal at the moment the fault occurs.

This is why freeze-frame information and waveform testing can be more informative than the code description alone.

Can P0368 Cause a No-Start?

Yes, it can.

If the ECM cannot obtain reliable camshaft position information, it may have difficulty synchronizing fuel injection and ignition.

Some engines will still start using other position information, while others can experience:

• Extended cranking

• Difficult starting

• Intermittent no-start

• Stalling immediately after starting

The exact behavior depends on the engine-management system.

The Correct Repair

The repair should follow the test results.

Possible repairs include:

• Replacing the defective Camshaft Position Sensor B

• Repairing a shorted signal wire

• Repairing damaged wiring

• Replacing connector terminals

• Correcting sensor power or ground

• Installing the correct sensor

• Correcting sensor installation

• Repairing an ECM circuit in rare cases

A camshaft sensor should not automatically be replaced simply because P0368 is stored.

If the signal wire is shorted to battery voltage, for example, a new sensor will not solve the problem.

Final Diagnostic Summary

P0368 – Camshaft Position Sensor “B” Circuit High Input (Bank 1) means the ECM has detected an abnormally high electrical signal on the monitored Camshaft Position Sensor B circuit for Bank 1.

The first suspects should generally be the sensor, its power and ground circuits, the signal wire, connector terminals and any unwanted voltage reaching the signal circuit.

The exact identity of Sensor B is manufacturer-specific, so the correct sensor must be established before testing or replacement.

Most importantly, P0368 is an electrical circuit-high code, not automatic proof of a bad timing chain, incorrect camshaft timing or a failed VVT system. A proper diagnosis should establish where the excessive signal is coming from before any component is replaced.