The P0347 code means the engine control module has detected a voltage signal from Camshaft Position Sensor “A” on Bank 2 that remains below its permitted range.
This is primarily an electrical fault. Common causes include a failed camshaft position sensor, a signal wire shorted to ground, missing sensor supply voltage, connector corrosion or excessive resistance in the circuit.
P0347 does not automatically mean the Bank 2 camshaft is mechanically out of time. It also doesn’t guarantee the sensor itself has failed. Test the circuit before firing the parts cannon—it’s loud, expensive and surprisingly poor at electrical diagnosis.
P0347 Quick Reference
| Item | Information |
|---|---|
| OBD-II code | P0347 |
| Official description | Camshaft Position Sensor “A” Circuit Low Bank 2 |
| System | Camshaft-position monitoring |
| Code type | Generic powertrain code |
| Primary fault | Sensor signal voltage below the expected threshold |
| Severity | Moderate to high |
| Safe to drive? | Only for a limited distance if the engine runs normally |
| Common causes | Failed sensor, grounded signal wire, missing supply voltage or connector damage |
| Typical repair range | Approximately $75–$2,500+, depending on the cause |
What Does the P0347 Code Mean?
P0347 stands for:
Camshaft Position Sensor “A” Circuit Low Bank 2
The camshaft position sensor monitors the rotational position of the camshaft. It sends an electrical signal to the engine control module, allowing the computer to determine which cylinder is approaching its combustion stroke.
The ECM may use this information to control:
- Sequential fuel injection
- Ignition timing
- Variable valve timing
- Cylinder identification
- Engine starting
- Misfire detection
- Camshaft-to-crankshaft synchronization
When the voltage from Bank 2 Camshaft Position Sensor “A” remains too low, the ECM stores P0347 and may illuminate the Check Engine Light.
The computer isn’t necessarily saying that the camshaft is in the wrong position. It’s saying the electrical signal used to determine that position is below the expected voltage threshold.
What Does “Circuit Low” Mean?
“Circuit low” means the ECM is seeing less voltage than it expects on the monitored camshaft-position circuit.
Depending on the vehicle and sensor design, the ECM may detect:
- Signal voltage stuck near zero
- Signal voltage consistently below its calibrated threshold
- Missing sensor supply voltage
- Signal circuit shorted to ground
- Excessive resistance reducing circuit voltage
- Sensor output that cannot switch between its expected voltage states
This makes P0347 different from a generic sensor malfunction or a camshaft-timing code.
A low-input code provides a specific electrical direction: begin by determining why the circuit voltage is being pulled down or why the sensor cannot produce its expected output.
What Are Bank 2 and Sensor “A”?
Bank 2
Bank 2 is the cylinder bank that does not contain cylinder number one.
Bank 2 is normally found on engines with two cylinder banks, including:
- V6 engines
- V8 engines
- V10 engines
- V12 engines
- Horizontally opposed engines
The physical location of Bank 2 varies by manufacturer. It may be on the driver or passenger side.
Never identify Bank 2 by guessing which cylinder head “looks like” Bank 2. Use the manufacturer’s cylinder-numbering diagram, firing order or service information.
Sensor “A”
On most dual-overhead-cam engines, Sensor “A” refers to the intake camshaft position sensor. Sensor “B” commonly refers to the exhaust camshaft position sensor.
Manufacturers don’t all use identical naming conventions, so confirm the sensor designation before testing or replacing anything.
A new sensor installed on the wrong bank remains a new sensor installed on the wrong bank. The ECM is rarely impressed by the effort.
How Serious Is the P0347 Code?
P0347 ranges from moderately serious to severe.
Some engines continue running by relying more heavily on crankshaft-position data. Others may become difficult to start, stall unexpectedly or enter a reduced-power mode.
Possible consequences include:
- Extended cranking
- Intermittent no-start condition
- Engine stalling
- Incorrect ignition timing
- Disabled variable valve timing
- Poor fuel economy
- Reduced acceleration
- Engine misfires
- Increased exhaust emissions
- Catalytic-converter damage from severe misfires
If the engine is running smoothly and P0347 is the only code present, limited driving may be possible while arranging diagnosis.
Stop driving if the vehicle:
- Stalls in traffic
- Misfires severely
- Produces timing-chain noise
- Has an oil-pressure warning
- Enters limp mode
- Loses substantial power
- Stores camshaft-to-crankshaft correlation codes
- Will not restart reliably
If the engine cranks without starting, use the engine cranks but won’t start diagnostic guide to separate a sensor-signal problem from fuel, spark and compression faults.
Common P0347 Symptoms
Common symptoms include:
- Illuminated Check Engine Light
- Hard starting
- Extended cranking
- Intermittent no-start
- Rough idle
- Engine hesitation
- Reduced acceleration
- Engine stalling
- Poor fuel economy
- Uneven power delivery
- Engine misfires
- Reduced-power mode
- Disabled variable valve timing
- Failed emissions inspection
Some vehicles may have no noticeable symptoms beyond the Check Engine Light.
An intermittent connector or partially damaged wire may occasionally pull the signal voltage below its threshold without completely disabling the sensor.
Common Causes of P0347
Possible causes include:
- Failed Bank 2 Camshaft Position Sensor “A”
- Signal circuit shorted to ground
- Missing sensor supply voltage
- Poor sensor ground
- Excessive resistance in the power or signal circuit
- Loose electrical connector
- Bent, spread or recessed connector terminals
- Corrosion inside the connector
- Oil contamination inside the connector
- Wiring melted against the exhaust
- Harness insulation worn through against a bracket
- Damaged wiring near the cylinder head
- Incorrect replacement sensor
- Improper sensor installation
- Excessive sensor air gap
- Metal debris attached to a magnetic sensor
- Damaged camshaft reluctor or trigger wheel
- Low cranking voltage
- Weak battery or poor engine ground
- ECM connector problem
- Failed ECM input circuit
Mechanical timing faults are less likely to cause a true circuit-low code by themselves. However, a damaged trigger wheel, excessive sensor clearance or abnormal camshaft movement may weaken the sensor output on certain systems.
P0345 vs P0346 vs P0347
These codes involve Bank 2 Camshaft Position Sensor “A,” but they identify different conditions.
| Code | Description | Main diagnostic focus |
| P0345 | Camshaft Position Sensor “A” Circuit Bank 2 | General circuit malfunction |
| P0346 | Camshaft Position Sensor “A” Range/Performance Bank 2 | Signal is present but implausible |
| P0347 | Camshaft Position Sensor “A” Circuit Low Bank 2 | Signal voltage is below its permitted threshold |
| P0348 | Camshaft Position Sensor “A” Circuit High Bank 2 | Signal voltage is above its permitted threshold |
| P0349 | Camshaft Position Sensor “A” Circuit Intermittent Bank 2 | Signal drops out or becomes unstable |
My Pro Street already covers the general P0345 Camshaft Position Sensor “A” circuit fault and provides a separate VQ35 P0345 camshaft-sensor service guide.
P0347 requires a narrower diagnostic approach. The technician must determine why the circuit is electrically low rather than simply treating every related code as a failed sensor.
P0347 vs P0021
P0347 and P0021 both involve the Bank 2 intake camshaft on many engines, but they don’t describe the same failure.
P0347 means the camshaft-position sensor signal voltage is too low.
P0021 means the Bank 2 intake camshaft is over-advanced or isn’t following its commanded position.
The P0021 Bank 2 camshaft timing guide focuses on engine oil, VVT-solenoid operation, camshaft-phaser problems and mechanical timing.
P0347 should remain focused on:
- Sensor supply voltage
- Sensor ground
- Signal voltage
- Wiring continuity
- Shorts to ground
- Connector condition
- Sensor output
If P0347 and P0021 appear together, repair the electrical sensor fault first. The ECM cannot accurately evaluate camshaft timing when the signal used to measure that timing is stuck near zero.
How Camshaft Position Sensors Work
Camshaft position sensors generally use one of two designs.
Hall-Effect Camshaft Sensors
A Hall-effect sensor normally uses three wires:
- Power supply
- Ground
- Signal
The sensor switches its output voltage as the camshaft trigger wheel passes the sensing element. An oscilloscope typically displays a digital square-wave pattern.
A Hall-effect circuit may store P0347 when:
- Supply voltage is missing
- Ground is poor
- The signal wire is shorted to ground
- The sensor cannot switch its output high
- The ECM input circuit pulls the signal low
Magnetic Camshaft Sensors
A magnetic or variable-reluctance sensor may use two wires and generate an alternating-current signal as the reluctor passes the sensor.
Its output depends on:
- Camshaft speed
- Sensor air gap
- Reluctor condition
- Sensor condition
- Wiring resistance
A magnetic sensor may produce insufficient voltage during cranking if its air gap is excessive, the battery is weak or the reluctor is damaged.
Confirm which sensor design the vehicle uses before applying voltage or selecting a test procedure. Guessing at sensor type is an efficient way to turn one electrical problem into two.
How to Diagnose the P0347 Code
1. Scan for Every Stored Code
Use a capable scan tool to retrieve stored, pending and permanent trouble codes.
Record codes involving:
- Bank 1 camshaft position
- Bank 2 camshaft position
- Crankshaft position
- System voltage
- Variable valve timing
- Camshaft timing
- Engine misfires
- Sensor-reference voltage
Multiple sensor-low codes may indicate a shared reference-voltage or ground problem rather than several failed sensors.
Record the freeze-frame information before clearing anything. Useful data includes:
- Engine speed
- Coolant temperature
- Battery voltage
- Vehicle speed
- Engine load
- Time since startup
If P0347 appeared during cranking with unusually low battery voltage, test the starting and charging system before replacing the sensor.
2. Check the Battery and Grounds
Measure battery voltage with the engine off, during cranking and while the engine is running.
Inspect:
- Battery terminals
- Engine ground straps
- Chassis grounds
- ECM grounds
- Ground connections near the cylinder head
Low system voltage can prevent a Hall-effect sensor from receiving proper power or reduce the cranking output of a magnetic sensor.
A battery that drops excessively during cranking may cause sensor codes even if the engine eventually starts.
3. Confirm Bank 2 Sensor “A”
Use service information to identify:
- Cylinder number one
- Bank 2
- Intake camshaft
- Sensor “A”
- Correct electrical connector
- Wire colors and terminal assignments
Do not assume a sensor’s location from a generic diagram. Engine layouts and cylinder numbering vary widely.
4. Inspect the Connector
Disconnect Bank 2 Camshaft Position Sensor “A” and inspect both sides of the connector.
Look for:
- Broken locking tabs
- Bent terminals
- Recessed pins
- Spread female terminals
- Green or white corrosion
- Oil contamination
- Water intrusion
- Damaged seals
- Loose terminal fit
- Evidence of overheating
Perform a terminal-drag test when appropriate. A terminal may look normal while making poor contact with the sensor pin.
Repair damaged terminals using the correct connector components. Twisting wires together and covering them with half a roll of electrical tape is not a harness repair. It’s a future diagnostic appointment.
5. Inspect the Wiring Harness
Follow the sensor harness as far as practical.
Pay special attention to wiring near:
- Exhaust manifolds
- Cylinder heads
- Valve covers
- Engine-mount brackets
- Timing covers
- Intake-manifold edges
- Harness retainers
- Previous repair areas
Look for insulation that is melted, crushed, stretched or rubbed through.
A signal wire touching grounded engine metal can hold the sensor signal low and store P0347.
Move the harness while monitoring sensor voltage or scan data. If the signal changes, suspect an intermittent internal wire break or loose terminal.
6. Check the Sensor Power Supply
Turn the ignition on and measure voltage at the sensor’s supply terminal using the manufacturer’s wiring diagram.
Depending on the system, the sensor may receive:
- Five-volt reference
- Eight-volt supply
- Battery voltage
- Another manufacturer-specific supply voltage
Do not automatically expect five volts.
If supply voltage is missing:
- Disconnect other components that share the circuit, if directed by service information.
- Check for a shorted sensor pulling down the shared supply.
- Test continuity between the sensor and ECM.
- Inspect related fuses and relays.
- Check the ECM connector.
- Test the ECM supply driver only after the external circuit passes inspection.
A different sensor on a shared reference circuit can pull voltage down and make the camshaft sensor look guilty.
7. Test the Sensor Ground
Measure voltage drop between the sensor ground and battery negative while the circuit is operating.
A resistance test performed with the circuit switched off may overlook a ground that fails under load.
Excessive ground resistance may prevent the sensor from producing the correct output, even if a basic continuity test shows the wire is connected.
Compare the measurement with manufacturer specifications.
8. Check the Signal Wire for a Short to Ground
Disconnect the sensor and ECM as required by the service procedure.
Test the signal wire for:
- Continuity from sensor to ECM
- Short to ground
- Short to voltage
- Excessive resistance
- Short to another circuit
If the signal remains low with the sensor disconnected, suspect a grounded signal wire or ECM input problem.
If the signal returns to its expected bias voltage after unplugging the sensor, the sensor itself may be internally shorted.
Circuit design varies, so verify the expected disconnected voltage before reaching a conclusion.
9. Compare Bank 1 and Bank 2 Signals
If the engine has matching sensors on both banks, compare their:
- Supply voltage
- Ground voltage drop
- Signal voltage
- Signal frequency
- Waveform shape
- Cranking behavior
- Hot-engine behavior
The Bank 1 sensor can provide a useful reference when manufacturer waveform information isn’t available.
Do not swap sensors between banks unless the parts are identical and the manufacturer’s procedure allows it. Sensor orientation, mounting depth and part numbers may differ.
10. Test the Sensor Signal
Back-probe the signal circuit without damaging the connector.
For a Hall-effect sensor, verify that the signal switches cleanly between its specified high and low states.
For a magnetic sensor, measure signal amplitude and frequency while cranking or running the engine.
A digital multimeter may show only an average voltage and miss rapid switching. Use an oscilloscope whenever possible.
11. Inspect the Waveform With an Oscilloscope
An oscilloscope can reveal problems that a resistance test or basic voltage measurement will miss.
Look for:
- Signal stuck low
- Weak signal amplitude
- Missing pulses
- Irregular pulse width
- Electrical noise
- Signal distortion
- Voltage dropping as the engine warms
- Waveform changes when the harness is moved
Compare Bank 2 Sensor “A” with the Bank 1 sensor and crankshaft-position signal.
If the power supply and ground remain correct but the Bank 2 signal cannot switch high, suspect the sensor, signal circuit or ECM input.
12. Inspect Sensor Installation and Air Gap
Remove the sensor if electrical testing points toward weak output rather than a direct short.
Inspect for:
- Cracked sensor housing
- Damaged sensing tip
- Metal debris
- Incorrect O-ring
- Sensor not fully seated
- Damaged mounting surface
- Incorrect replacement sensor
- Excessive air gap
- Contact between the sensor and reluctor
An incorrect O-ring or debris beneath the mounting flange may prevent the sensor from seating completely.
On a magnetic sensor, even a small increase in air gap may substantially reduce signal voltage during cranking.
13. Inspect the Reluctor or Trigger Wheel
If the sensor and external circuit test correctly, inspect the camshaft trigger wheel where accessible.
Check for:
- Bent trigger teeth
- Missing material
- Cracks
- Excessive runout
- Loose reluctor
- Incorrect installation
- Debris
- Camshaft end play
A damaged trigger wheel normally causes waveform irregularities rather than a constant electrical low, but it can reduce signal amplitude on certain sensor designs.
14. Test the ECM Last
Suspect the ECM only after confirming:
- Proper sensor supply voltage
- Reliable sensor ground
- Correct signal-wire integrity
- Correct sensor operation
- Proper connector terminal tension
- Acceptable waveform at the sensor
- Incorrect waveform or voltage at the ECM terminal
If the waveform is correct at the sensor but incorrect at the ECM, inspect the harness and connectors between them.
If the correct waveform reaches the ECM and P0347 still returns, check for software updates and follow the manufacturer’s ECM diagnostic procedure.
Control-module replacement should remain the final step. Computers are expensive, require programming and are frequently blamed for wiring faults they didn’t create.
Common P0347 Diagnostic Mistakes
Avoid these common mistakes:
- Replacing the sensor without measuring voltage
- Confusing Bank 1 with Bank 2
- Testing the exhaust sensor instead of Sensor “A”
- Ignoring a weak battery
- Assuming every sensor uses a five-volt supply
- Checking continuity without performing a voltage-drop test
- Ignoring spread connector terminals
- Overlooking oil inside the connector
- Missing a shared reference-voltage problem
- Using only a resistance test on a Hall-effect sensor
- Assuming P0347 means the timing chain has failed
- Replacing the ECM before testing the complete circuit
- Installing an incorrect aftermarket sensor
The phrase “circuit low” is useful. It tells you to follow the voltage and find where it disappears. It does not translate to “buy sensor immediately.”
How Do You Fix the P0347 Code?
The correct repair depends on the confirmed cause.
Possible repairs include:
- Cleaning and securing the sensor connector
- Replacing damaged connector terminals
- Repairing a signal wire shorted to ground
- Repairing the sensor supply circuit
- Repairing a high-resistance ground
- Rerouting wiring away from heat or sharp brackets
- Repairing shared reference-voltage wiring
- Replacing Bank 2 Camshaft Position Sensor “A”
- Installing the correct OEM-quality sensor
- Correcting sensor installation
- Removing debris from the sensor tip
- Correcting excessive sensor clearance
- Repairing or replacing a damaged reluctor wheel
- Replacing a weak battery
- Repairing engine or ECM grounds
- Updating ECM software
- Replacing and programming the ECM when testing confirms failure
Do not replace timing components solely because P0347 is present. Verify mechanical timing only when other codes, waveform evidence or engine symptoms justify it.
P0347 Repair Costs
Repair costs vary by vehicle, accessibility and the actual failure.
| Repair | Estimated cost |
| Diagnostic inspection | $100–$250 |
| Clean or secure connector | $50–$150 |
| Replace sensor connector | $100–$350 |
| Repair damaged wiring | $100–$700 |
| Replace camshaft position sensor | $150–$500 |
| Replace battery or repair grounds | $150–$500 |
| Repair shared reference circuit | $150–$900 |
| Replace damaged reluctor or trigger wheel | $500–$2,500+ |
| ECM software update | $100–$300 |
| Replace and program ECM | $800–$2,500+ |
These are general estimates. Labor time can increase substantially when the sensor is buried beneath an intake manifold, pressed against the firewall or hidden wherever the engineering department found the least convenient remaining space.
Can You Drive With a P0347 Code?
Limited driving may be possible if:
- The engine starts normally
- It runs smoothly
- No correlation codes are present
- The Check Engine Light isn’t flashing
- There is no timing-system noise
- The vehicle doesn’t stall
Stop driving if:
- The engine stalls unexpectedly
- Starting becomes unreliable
- The engine misfires severely
- The Check Engine Light flashes
- The vehicle enters reduced-power mode
- Mechanical rattling develops
- Oil pressure is low
- Acceleration becomes unsafe
A low camshaft-sensor signal may disappear completely without warning. Diagnose the fault before trusting the vehicle for a long trip or a commute where stalling would create a safety risk.
P0347 Frequently Asked Questions
Does P0347 mean the camshaft position sensor is bad?
Not necessarily. A failed sensor can cause P0347, but so can a grounded signal wire, missing supply voltage, poor ground, connector damage or ECM circuit problem.
Where is Bank 2 Camshaft Position Sensor “A”?
Bank 2 is the side of the engine that does not contain cylinder number one. Sensor “A” usually monitors the intake camshaft. Confirm the exact location using vehicle-specific service information.
What voltage should the camshaft sensor receive?
It depends on the sensor and vehicle. Some sensors receive five volts, while others receive battery voltage or another specified supply. Consult the correct wiring diagram.
Can a weak battery cause P0347?
Yes. Low cranking voltage may reduce sensor supply voltage or weaken the output from a magnetic sensor.
Can dirty oil cause P0347?
Dirty oil is more commonly associated with VVT performance and camshaft-timing codes. It does not usually cause a direct circuit-low fault unless contamination damages the sensor connector or wiring.
Can a timing chain cause P0347?
A stretched timing chain generally causes timing-performance or correlation codes rather than a direct circuit-low code. However, trigger-wheel damage or excessive camshaft movement could weaken the sensor signal on some engines.
Can a bad crankshaft sensor cause P0347?
A crankshaft sensor fault can interfere with camshaft correlation and engine operation, but P0347 specifically identifies a low Bank 2 camshaft-sensor circuit. Test the circuit named by the code while also checking related crankshaft codes.
Can I test the camshaft sensor with a multimeter?
A multimeter can check supply voltage, ground, continuity and basic signal activity. An oscilloscope is better for evaluating switching voltage, waveform quality and missing pulses.
Will clearing P0347 fix it?
Clearing the code only resets the warning temporarily. If the low-voltage condition remains, P0347 will return.
Should I replace both Bank 1 and Bank 2 sensors?
No. Replace only the component proven defective unless the manufacturer recommends replacing matched sensors together or both units show the same failure.
Final Thoughts
P0347 means the signal voltage from Bank 2 Camshaft Position Sensor “A” is below the range expected by the ECM.
Begin diagnosis by scanning for related codes, recording freeze-frame data and checking battery voltage. Confirm Bank 2 and Sensor “A,” then inspect the connector, wiring, sensor power supply and ground.
Test the signal circuit for a short to ground and compare Bank 2 operation with Bank 1. Use an oscilloscope to determine whether the sensor output is stuck low, weak or missing.
Replace the sensor only after confirming it has proper power and ground but cannot produce the correct signal. If the sensor works normally, continue testing the wiring, terminal connections and ECM input.
For more diagnostic information, visit the complete P-series OBD-II code guide, browse the OBDII Doctor archive or use the Car Symptoms Encyclopedia to investigate the vehicle’s actual behavior.
The code points toward a low circuit. Follow the voltage before replacing parts. Electricity may be invisible, but apparently it still expects us to do paperwork.
