The P0392 OBD-II trouble code means the powertrain control module has detected voltage below the expected range in the Camshaft Position Sensor “B” circuit on Bank 2.
On a Hall-effect sensor, the signal may remain stuck near ground instead of switching between its normal high and low voltage states. On a magnetic sensor, the generated waveform may be too weak for the PCM to recognize reliably.
A failed sensor can cause P0392, but it is not the only possibility. A signal wire shorted to ground, missing sensor supply voltage, damaged connector, excessive sensor air gap or weak magnetic output can all create the same low-input condition.
Sensor B commonly monitors the exhaust camshaft on a DOHC engine, but manufacturers can define it differently. Bank 2 is the cylinder bank that does not contain cylinder number one. Confirm both details before replacing parts, because changing the wrong sensor remains a remarkably effective way to preserve the original code.
P0392 Quick Reference
| Item | Details |
|---|---|
| Trouble code | P0392 |
| Code definition | Camshaft Position Sensor “B” Circuit Low Input Bank 2 |
| System affected | Bank 2 camshaft-position monitoring |
| Likely sensor | Usually the Bank 2 exhaust camshaft sensor |
| Fault type | Sensor B signal voltage below the expected range |
| Common causes | Short to ground, missing sensor power, weak sensor, wiring damage or excessive air gap |
| Common symptoms | Check Engine Light, hard starting, rough running, hesitation or reduced power |
| Typical severity | Moderate |
| Safe to drive? | Possibly for a short distance if the engine runs normally |
| Repair difficulty | Intermediate electrical diagnosis |
What Does the P0392 Code Mean?
P0392 indicates that the Bank 2 Camshaft Position Sensor B signal remains below the voltage threshold expected by the PCM.
The PCM uses this sensor to help determine:
- Bank 2 camshaft position
- Cylinder identification
- Sequential fuel-injection timing
- Ignition timing
- Variable-valve-timing operation
- Startup synchronization
- Misfire-monitoring accuracy
- Camshaft-to-crankshaft relationship
The precise meaning of “low input” depends on the sensor design.
A Hall-effect sensor normally switches between defined high and low voltage levels. If the signal stays near zero volts or cannot reach its required high state, the PCM may set P0392.
A magnetic sensor produces an alternating-current waveform. If the output amplitude remains below the PCM’s recognition threshold, the module may also interpret the condition as a low input.
P0392 identifies the voltage condition. It does not prove that the sensor itself has failed.
What Does Sensor B Mean?
On many dual-overhead-cam engines:
- Sensor A monitors the intake camshaft
- Sensor B monitors the exhaust camshaft
This is common, but it is not universal. The manufacturer may identify Sensor B by function or location rather than simply intake versus exhaust.
Before testing, verify:
- Whether Sensor B monitors the intake or exhaust camshaft
- Its exact location
- Connector pinout
- Sensor design
- Supply-voltage specification
- Ground circuit
- Expected waveform
The wiring diagram gets the final vote.
What Does Bank 2 Mean?
Bank 2 is the cylinder bank that does not contain cylinder number one.
Bank 2 is not always:
- The driver side
- The passenger side
- The front cylinder bank
- The rear cylinder bank
- The left side
- The right side
Its location depends on the engine family and vehicle layout.
P0392 normally applies to V-type or opposed engines with two cylinder banks. Inline engines generally use only Bank 1.
How the Camshaft-Position Sensor Works
The camshaft-position sensor reads a toothed, slotted or magnetized trigger wheel attached to the camshaft, phaser or actuator.
As the camshaft rotates, the sensor produces electrical pulses. The PCM analyzes their voltage, spacing and timing to determine the camshaft’s position.
Two common sensor types are used.
Hall-Effect Camshaft Sensor
A Hall-effect sensor typically has three circuits:
- Power or reference voltage
- Sensor ground
- Digital signal output
The signal switches between its specified high and low states as the camshaft trigger passes the sensor.
A low-input condition may result from:
- Missing sensor power
- Signal wire shorted to ground
- Failed internal sensor electronics
- Excessive voltage drop in the supply circuit
- Damaged trigger relationship
- PCM input pulling the signal low
Magnetic Camshaft Sensor
A magnetic or variable-reluctance sensor commonly uses two wires and generates its own alternating-current signal.
Its output is affected by:
- Camshaft speed
- Sensor air gap
- Sensor magnet strength
- Trigger-wheel condition
- Wiring resistance
- Temperature
- Metal contamination
A weak magnetic sensor may produce a usable waveform at higher RPM but insufficient voltage during cranking or idle.
Symptoms of a P0392 Code
Possible symptoms include:
- Illuminated Check Engine Light
- Extended cranking
- Hard starting
- Engine cranks but does not start
- Rough idle
- Engine hesitation
- Reduced engine power
- Poor throttle response
- Misfire-like operation
- Increased fuel consumption
- Variable valve timing disabled
- Engine stalling
- Limp-home mode
- Difficult hot or cold starting
- No noticeable symptoms beyond the warning light
Some vehicles can operate using the crankshaft-position sensor and other camshaft inputs. The PCM may disable variable valve timing or use a backup fuel-injection strategy.
If the engine turns over normally but refuses to start, use the engine cranks but won’t start diagnostic guide to verify spark, injector command, fuel pressure and synchronization data.
Common Causes of P0392
Potential causes include:
- Signal Wire Shorted to GroundDamaged insulation may allow the Sensor B signal circuit to contact the cylinder head, engine block or chassis.
- Failed Bank 2 Camshaft Position Sensor BInternal electronics or windings may fail and produce little or no usable signal voltage.
- Missing Sensor Supply VoltageA Hall-effect sensor cannot switch its output correctly without its required power supply.
- High Resistance in the Sensor-Power CircuitCorrosion or loose terminals can reduce voltage reaching the sensor.
- Open Sensor-Power WireA broken supply conductor may leave the active sensor unable to operate.
- Poor Sensor GroundAn unstable or high-resistance ground may prevent correct sensor operation.
- Open Magnetic-Sensor WindingAn internally open magnetic pickup may produce no useful output.
- High Resistance in the Signal CircuitCorroded terminals or damaged wiring can reduce the signal before it reaches the PCM.
- Oil-Contaminated ConnectorEngine oil entering the connector can affect terminal contact and circuit resistance.
- Water IntrusionMoisture can corrode terminals or bridge the signal circuit to ground.
- Bent or Pushed-Back Connector TerminalPoor terminal contact may interrupt the signal or sensor supply.
- Excessive Sensor Air GapToo much clearance between a magnetic sensor and trigger wheel can reduce output amplitude.
- Metal Debris on the Sensor TipMagnetic contamination can interfere with the sensor’s ability to detect individual trigger features.
- Incorrect Sensor InstallationDebris beneath the mounting flange or an incorrectly seated sensor can change the air gap.
- Incorrect Replacement SensorA sensor with the wrong depth or electrical characteristics may produce inadequate output.
- Damaged Camshaft ReluctorMissing or damaged trigger features can reduce the expected waveform.
- Low Battery Voltage or Slow CrankingSlow camshaft rotation can reduce magnetic-sensor output during startup.
- PCM Input-Circuit FaultAn internal PCM problem may pull the signal low or interpret it incorrectly, although this is less common.
How Serious Is P0392?
P0392 is usually a moderate-severity fault.
The engine may continue running if the PCM can rely on other camshaft or crankshaft signals. However, the fault may cause:
- Extended cranking
- Reduced power
- Poor fuel economy
- Rough running
- Disabled variable valve timing
- Intermittent stalling
- A no-start condition
Diagnosis should be scheduled promptly, particularly if starting becomes unreliable.
Do not continue driving if the engine stalls, misfires heavily, loses substantial power or displays a flashing Check Engine Light.
P0390 vs. P0391 vs. P0392
These codes affect the same Bank 2 Sensor B system but describe different conditions.
| Code | Definition | Primary diagnostic focus |
| P0390 | Sensor B Circuit Malfunction Bank 2 | General circuit failure or unusable signal |
| P0391 | Sensor B Circuit Range/Performance Bank 2 | Signal exists but its waveform or response is implausible |
| P0392 | Sensor B Circuit Low Input Bank 2 | Signal voltage remains below the expected threshold |
P0392 narrows the diagnostic direction toward a low-voltage condition. Shorts to ground, missing supply voltage and weak sensor output deserve particular attention.
P0392 vs. P0347
P0347 is the corresponding low-input code for Camshaft Position Sensor A on Bank 2.
| Code | Bank | Sensor | Fault |
| P0347 | 2 | Sensor A | Circuit low input |
| P0392 | 2 | Sensor B | Circuit low input |
On many DOHC engines, P0347 applies to the Bank 2 intake camshaft sensor while P0392 applies to the Bank 2 exhaust camshaft sensor.
P0392 vs. P0367
P0367 applies to Camshaft Position Sensor B on Bank 1.
| Code | Bank | Sensor | Fault |
| P0367 | 1 | Sensor B | Circuit low input |
| P0392 | 2 | Sensor B | Circuit low input |
If both codes appear together, inspect shared sensor power, grounds and PCM circuits before assuming that both sensors failed at the same time.
P0392 vs. P0393
P0392 and P0393 identify opposite voltage conditions.
| Code | Electrical condition | Typical diagnostic direction |
| P0392 | Signal voltage too low | Short to ground, missing supply, weak output |
| P0393 | Signal voltage too high | Short to voltage, open ground, signal stuck high |
The difference matters. Testing a low-input circuit as though it were shorted to power sends the diagnosis in precisely the wrong electrical direction—which is technically still a direction, just not a useful one.
How to Diagnose the P0392 Code
The correct test procedure depends on whether Sensor B is a Hall-effect, magnetoresistive or magnetic sensor.
1. Confirm P0392
Connect a capable scan tool and record:
- P0392
- Current, pending and history codes
- Freeze-frame information
- Engine RPM
- Battery voltage
- Engine coolant temperature
- Vehicle speed
- Engine load
- Camshaft synchronization
- Crankshaft synchronization
- Desired and actual Bank 2 Sensor B positions
- VVT command data
Do not clear the code until the freeze-frame information has been recorded.
2. Check for Related Codes
Look for codes involving:
- P0390 through P0394
- Bank 1 Sensor B
- Bank 2 Sensor A
- Crankshaft-position sensors
- Camshaft correlation
- Sensor reference voltage
- System voltage
- VVT control circuits
- PCM communication
Several sensor-low codes appearing together may indicate a shared reference-voltage or ground problem.
3. Identify Bank 2 and Sensor B
Use factory service information to determine:
- Cylinder number-one location
- Bank 2 location
- Whether Sensor B monitors intake or exhaust
- Sensor connector pinout
- Sensor type
- Supply-voltage specification
- Expected signal range
- PCM connector terminals
- Sensor air-gap specification
Do not begin electrical tests until the correct sensor has been identified.
4. Inspect the Sensor and Connector
Switch the ignition off and inspect:
- Sensor housing
- Connector lock
- Terminal tension
- Bent or pushed-back terminals
- Oil contamination
- Water intrusion
- Corrosion
- Damaged connector seals
- Incorrect sensor mounting
- Debris beneath the sensor flange
Oil inside the connector may indicate a leaking sensor. Clean the connector and determine whether oil has migrated into the wiring.
5. Inspect the Wiring Harness
Follow the Bank 2 Sensor B circuit toward the PCM.
Look for:
- Harness contact with the exhaust
- Wiring pinched beneath the valve cover
- Insulation rubbed through against brackets
- Oil-soaked wiring
- Melted loom
- Damaged shielding
- Improper splices
- Stretching from prior engine work
- Wiring crushed between components
Pay special attention to sections where the harness touches the cylinder head or crosses near ground points.
6. Check Battery and Cranking Voltage
Measure:
- Battery voltage with the engine off
- Minimum voltage during cranking
- Battery-cable voltage drop
- Engine-ground voltage drop
- Charging voltage
- Alternator ripple
Low cranking speed can weaken magnetic-sensor output. Unstable voltage can also interfere with active-sensor operation and PCM synchronization.
Correct major voltage problems before condemning the sensor.
7. Verify Hall-Effect Sensor Power
If Sensor B is an active three-wire sensor, switch the ignition on and test its supply voltage.
The circuit may use:
- Five volts
- Eight volts
- Battery voltage
- Another manufacturer-specified supply
If supply voltage is missing:
- Disconnect Sensor B.
- Recheck the supply circuit.
- Inspect for a short to ground.
- Check other sensors sharing the supply.
- Test continuity between Sensor B and the PCM.
- Verify PCM powers and grounds.
If the reference voltage returns when Sensor B is disconnected, the sensor may be internally shorted.
8. Test Sensor Ground
Perform a voltage-drop test while the sensor is connected and operating.
Check:
- Ground-terminal contact
- Shared ground splices
- Cylinder-head grounds
- Engine-to-body straps
- PCM grounds
A simple continuity beep does not prove that the ground can operate correctly under load.
Repair excessive voltage drop before continuing.
9. Measure the Hall-Effect Signal
Back-probe the signal circuit with a high-impedance digital multimeter or oscilloscope.
During cranking or engine operation, the signal should switch between specified high and low states.
A P0392 waveform may show:
- Signal continuously near zero volts
- High state that never reaches specification
- Severely reduced amplitude
- Brief low-voltage pulses without normal switching
- Voltage recovering when the sensor is disconnected
A multimeter may average a switching waveform. An oscilloscope provides a much clearer view.
10. Test for a Short to Ground
Disconnect the sensor and PCM according to service information.
Test the signal circuit for continuity to:
- Engine ground
- Chassis ground
- Sensor low-reference circuits
- Grounded shielding
- Adjacent wiring
Move the harness while observing the meter.
Do not measure resistance on a powered circuit.
11. Test a Magnetic Sensor
For a two-wire magnetic Sensor B:
- Check resistance only when a specification is provided
- Check for an open winding
- Check both circuits for shorts to ground
- Measure AC output during cranking
- Inspect waveform amplitude
- Compare output with Bank 1 Sensor B
- Repeat testing when the sensor is hot
A magnetic sensor can pass a resistance test and still produce insufficient waveform amplitude.
12. Capture and Compare Waveforms
Use a multi-channel oscilloscope to compare:
- Bank 1 Sensor B
- Bank 2 Sensor B
- Crankshaft-position signal
A healthy Bank 1 waveform and weak Bank 2 waveform point toward:
- Bank 2 Sensor B
- Bank 2 sensor air gap
- Bank 2 wiring resistance
- Bank 2 reluctor condition
If both Sensor B signals are low, inspect shared power, ground, system voltage and PCM operation.
13. Compare the Signal at the Sensor and PCM
Measure Bank 2 Sensor B directly at the sensor and then at the PCM connector.
Possible findings include:
- Low signal at both locations: sensor, power, ground or trigger problem
- Normal signal at sensor but low at PCM: harness resistance or partial short to ground
- Normal signal at PCM but low scan data: PCM input or software problem
- Signal changes when the harness moves: connector or conductor damage
This comparison helps locate exactly where the signal is being lost.
14. Check Sensor Air Gap
Measure sensor-to-trigger clearance when the design allows it.
Excessive clearance may result from:
- Debris beneath the sensor
- Incorrect sensor dimensions
- Improper installation
- Damaged mounting surface
- Reluctor runout
- Camshaft end play
- Missing or incorrect spacer
Follow the manufacturer’s specification. Moving the sensor too close can allow the rotating trigger to strike and destroy it.
15. Inspect the Camshaft Reluctor
Look for:
- Bent trigger tabs
- Missing features
- Cracks
- Metal debris
- Loose mounting
- A shifted reluctor
- Damage from previous repairs
A repeatable missing or weak pulse at the same point in every camshaft revolution may identify reluctor damage.
16. Check for Heat-Related Failure
If P0392 appears when the engine is hot:
- Monitor the waveform from cold start
- Compare hot and cold supply voltage
- Compare hot and cold signal amplitude
- Move the harness carefully
- Apply controlled heat only according to approved procedures
- Cool the sensor and repeat the test
Internal sensor electronics or windings may weaken as temperature increases.
17. Evaluate Mechanical Timing Only With Supporting Codes
P0392 is primarily an electrical low-input fault.
Investigate mechanical timing only when:
- The signal voltage and waveform are electrically valid
- Correlation codes are present
- Timing codes accompany P0392
- The engine has abnormal mechanical noise
- Recent timing-system repairs were performed
A stretched chain or sticking phaser generally produces performance or correlation faults rather than a signal that remains electrically low.
18. Check the PCM Last
Consider PCM failure only after confirming:
- Correct Bank 2 identification
- Correct Sensor B identification
- Stable sensor supply voltage
- Reliable sensor ground
- No signal short to ground
- Correct signal continuity
- Proper sensor installation
- Good reluctor condition
- Valid battery and charging voltage
- No applicable software update
PCM replacement may require programming, security initialization and camshaft or crankshaft relearn procedures.
Common P0392 Diagnostic Mistakes
Avoid these common mistakes:
- Testing Sensor A instead of Sensor B
- Testing Bank 1 instead of Bank 2
- Assuming Sensor B always means exhaust
- Replacing the sensor without checking its supply voltage
- Ignoring a signal wire shorted to ground
- Approving the ground with only a continuity beep
- Using Hall-effect tests on a magnetic sensor
- Relying only on sensor resistance
- Ignoring low cranking speed
- Overlooking excessive sensor air gap
- Using a conventional test light on a PCM signal circuit
- Damaging connector terminals with oversized probes
- Replacing timing components before testing the electrical circuit
- Replacing the PCM before isolating the harness
Repairs That May Fix P0392
Possible repairs include:
- Replacing Bank 2 Camshaft Position Sensor B
- Repairing a signal wire shorted to ground
- Restoring missing sensor supply voltage
- Repairing an open sensor-power wire
- Repairing a poor sensor ground
- Cleaning oil or corrosion from the connector
- Replacing loose or damaged terminals
- Replacing a broken connector
- Repairing high resistance in the signal circuit
- Correcting sensor installation
- Correcting excessive sensor air gap
- Cleaning debris from the sensor tip
- Installing the correct replacement sensor
- Repairing a damaged camshaft reluctor
- Repairing battery cables or engine grounds
- Updating PCM software
- Replacing and programming the PCM after confirmed failure
Estimated P0392 Repair Costs
Actual pricing depends on the vehicle, sensor location and root cause.
| Repair | Estimated cost |
| Diagnostic inspection | $100–$250 |
| Connector or terminal repair | $100–$400 |
| Camshaft Position Sensor B replacement | $180–$550 |
| Sensor power or ground repair | $120–$450 |
| Major harness repair | $350–$1,200 |
| Camshaft-reluctor repair | $600–$2,000 |
| PCM software update | $100–$300 |
| PCM replacement and programming | $800–$2,500 |
A sensor near the front of the cylinder head may be easy to replace. One buried behind an intake manifold or against the firewall will naturally require more labor, because accessibility continues its undefeated run as a pricing multiplier.
Can You Drive With P0392?
You may be able to drive a short distance if the engine starts, runs smoothly and does not stall.
Do not continue driving if:
- The engine stalls
- Starting becomes unreliable
- Power drops substantially
- The engine misfires heavily
- The Check Engine Light flashes
- Multiple camshaft or crankshaft codes appear
- Abnormal mechanical noise develops
Review what the Check Engine Light means for additional warning-light guidance.
How to Verify the Repair
After completing the repair:
- Reconnect every sensor and module.
- Confirm connector-terminal engagement.
- Secure the harness away from heat and moving components.
- Clear current and pending codes.
- Monitor Bank 2 Sensor B during cranking.
- Verify correct sensor supply and ground.
- Confirm that the waveform reaches its proper high and low states.
- Compare Bank 1 and Bank 2 Sensor B waveforms.
- Warm the engine fully.
- Recreate the freeze-frame conditions.
- Complete the required drive cycle.
- Perform any manufacturer-specified relearn.
- Check for pending codes.
The repair is confirmed when Bank 2 Sensor B voltage remains within specification, its waveform stays stable and P0392 does not return.
Frequently Asked Questions
What does the P0392 code mean?
P0392 means the PCM detected voltage below the expected range in the Bank 2 Camshaft Position Sensor B circuit.
Is Sensor B the exhaust camshaft sensor?
Sensor B commonly monitors the exhaust camshaft on a DOHC engine, but the manufacturer’s service information should confirm it.
Which side is Bank 2?
Bank 2 is the cylinder bank that does not contain cylinder number one. Its physical location varies by engine.
Does P0392 mean the camshaft sensor is bad?
Not necessarily. The sensor may have failed, but a short to ground, missing supply voltage, damaged wiring or excessive sensor air gap can cause the same code.
What is the difference between P0390 and P0392?
P0390 identifies a general Sensor B circuit malfunction. P0392 specifically means the Bank 2 Sensor B signal voltage is below the expected range.
What is the difference between P0391 and P0392?
P0391 indicates an implausible waveform or performance condition. P0392 identifies a consistently low electrical signal.
What is the difference between P0347 and P0392?
P0347 applies to Sensor A on Bank 2. P0392 applies to Sensor B on Bank 2.
What is the difference between P0367 and P0392?
P0367 applies to Sensor B on Bank 1. P0392 applies to Sensor B on Bank 2.
Can low battery voltage cause P0392?
Yes. Low voltage can disrupt an active sensor and reduce cranking speed, which may weaken magnetic-sensor output.
How do you diagnose P0392?
Identify Bank 2 Sensor B, verify its power and ground, check the signal circuit for a short to ground and inspect the waveform with an oscilloscope.
Final Thoughts
P0392 means the Bank 2 Camshaft Position Sensor B signal is electrically lower than the PCM expects.
Begin by confirming the correct bank and sensor. Inspect the connector, verify sensor power and ground and test the signal wire for a short to ground. An oscilloscope comparison between Bank 1 and Bank 2 can then reveal whether Sensor B is stuck low, producing weak amplitude or losing voltage in the harness.
Replacing the sensor may be the correct repair. Proving why the signal is low before buying it remains the more reliable approach—and produces fewer mystery sensors collecting dust on the workbench.
Visit the OBD-II Doctor for additional diagnostic guides or browse the complete P-series OBD-II code reference to identify related powertrain faults.
