The P0348 code means the engine control module has detected excessive voltage in the Camshaft Position Sensor “A” circuit on Bank 2.
This is primarily an electrical fault. Common causes include a signal wire shorted to a voltage source, an open sensor ground, damaged connector terminals, a failed camshaft position sensor or an ECM input problem.
P0348 doesn’t automatically mean the camshaft is mechanically out of time. Before replacing sensors, phasers or half the timing system, test the circuit and find out why the signal is stuck high.
Parts stores already have electricity. They don’t need additional donations.
P0348 Quick Reference
| Item | Information |
|---|---|
| OBD-II code | P0348 |
| Official description | Camshaft Position Sensor “A” Circuit High Bank 2 |
| System | Camshaft-position monitoring |
| Code type | Generic powertrain code |
| Primary fault | Sensor signal voltage above the expected threshold |
| Severity | Moderate to high |
| Safe to drive? | Limited driving only if the engine runs normally |
| Common causes | Short to voltage, open ground, damaged wiring or failed sensor |
| Typical repair range | Approximately $75–$2,500+, depending on the cause |
What Does the P0348 Code Mean?
P0348 stands for:
Camshaft Position Sensor “A” Circuit High Bank 2
The camshaft position sensor monitors the rotational position of the camshaft. It sends an electrical signal to the engine control module or powertrain control module.
The computer uses that signal to control or monitor:
- Sequential fuel injection
- Ignition timing
- Cylinder identification
- Engine starting
- Variable valve timing
- Camshaft-to-crankshaft synchronization
- Misfire detection
When the voltage on the Bank 2 Sensor “A” circuit remains above the permitted threshold, the ECM stores P0348 and illuminates the Check Engine Light.
The code identifies an electrical high-input condition. It does not automatically identify which component caused it.
What Does “Circuit High” Mean?
“Circuit high” means the ECM is receiving more voltage than it expects from the monitored camshaft-position circuit.
Depending on the vehicle and circuit design, the ECM may detect:
- Signal voltage stuck high
- Signal voltage that never switches low
- Signal circuit shorted to the supply circuit
- Signal wire shorted to battery voltage
- Open or high-resistance sensor ground
- An internally failed sensor
- Incorrect pull-up voltage
- ECM input voltage above its calibrated threshold
On a Hall-effect sensor, the signal normally switches between high and low voltage states as the camshaft trigger wheel rotates. If the signal remains high instead of switching, the ECM cannot reliably determine camshaft position.
An open signal circuit may also appear high on some systems because the ECM uses an internal pull-up resistor. That possibility depends on the circuit design, which is why the correct wiring diagram matters.
P0348 provides a diagnostic direction: determine why the voltage is high or why the circuit cannot return to its expected low state.
What Are Bank 2 and Sensor “A”?
Bank 2
Bank 2 is the cylinder bank that does not contain cylinder number one.
It normally appears on engines with two cylinder banks, including:
- V6 engines
- V8 engines
- V10 engines
- V12 engines
- Horizontally opposed engines
Bank 2 may be on the driver or passenger side, depending on the manufacturer and engine design.
Use the manufacturer’s cylinder-numbering diagram, firing order or repair information to identify it correctly.
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.
The naming convention isn’t universal. Confirm the component using vehicle-specific service information before disconnecting or replacing anything.
Replacing the wrong sensor can create a very clean repair invoice while leaving the original problem completely untouched.
How Serious Is the P0348 Code?
P0348 should be considered a moderately serious fault.
Some vehicles may continue running by relying more heavily on crankshaft-position information. Other vehicles may experience hard starting, stalling, misfires or reduced engine power.
Possible consequences include:
- Extended cranking
- Intermittent no-start condition
- Engine stalling
- Reduced acceleration
- Disabled variable valve timing
- Poor fuel economy
- Incorrect ignition or injection timing
- Engine misfires
- Increased emissions
- Catalytic-converter damage from severe misfires
Limited driving may be possible if the engine starts normally, runs smoothly and has no mechanical timing noise.
Stop driving if:
- The engine stalls
- The Check Engine Light flashes
- Severe misfires develop
- The vehicle enters reduced-power mode
- Acceleration becomes unsafe
- The engine produces timing-chain noise
- An oil-pressure warning appears
- The vehicle becomes difficult to restart
If the engine cranks but doesn’t start, use the engine cranks but won’t start guide to separate the camshaft-signal problem from fuel, ignition and compression faults.
Common P0348 Symptoms
Symptoms vary by engine and control strategy.
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
- Engine misfires
- Reduced-power mode
- Disabled variable valve timing
- Failed emissions inspection
Some vehicles may have no noticeable symptoms beyond the warning light.
A loose connector or damaged wire may cause the circuit voltage to rise only under heat, vibration or engine movement. The code may appear intermittently even when the vehicle seems to run normally.
Common Causes of P0348
Possible causes include:
- Signal wire shorted to sensor supply voltage
- Signal wire shorted to battery voltage
- Open or high-resistance sensor ground
- Failed Bank 2 Camshaft Position Sensor “A”
- Internally shorted sensor
- Open signal wire on a pull-up circuit
- Loose sensor connector
- Bent or recessed connector terminals
- Spread female terminals
- Corrosion inside the connector
- Oil contamination inside the connector
- Water intrusion
- Wiring melted against an exhaust component
- Harness insulation rubbed through
- Incorrect replacement sensor
- Incorrect terminal placement after connector repair
- Aftermarket wiring or alarm-system interference
- Poor engine or ECM ground
- Damaged ECM connector
- Failed ECM input circuit
- Incorrect ECM programming or calibration
Mechanical timing wear generally doesn’t cause a true circuit-high code by itself. A damaged reluctor or excessive sensor clearance may affect the waveform, but that normally creates a performance, correlation or missing-signal problem rather than a signal held electrically high.
P0345 vs P0346 vs P0347 vs P0348
These codes apply to Bank 2 Camshaft Position Sensor “A,” but each identifies a different failure condition.
| 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 | Implausible signal or waveform |
| P0347 | Camshaft Position Sensor “A” Circuit Low Bank 2 | Voltage below the expected threshold |
| P0348 | Camshaft Position Sensor “A” Circuit High Bank 2 | Voltage above the expected threshold |
| P0349 | Camshaft Position Sensor “A” Circuit Intermittent Bank 2 | Signal repeatedly drops out or becomes unstable |
My Pro Street already provides a general P0345 Camshaft Position Sensor “A” circuit guide and a vehicle-specific guide covering the P0345 VQ35 camshaft position sensor.
P0348 requires a narrower diagnostic approach centered on excessive voltage, an open ground or a signal that cannot switch low.
P0348 vs P0021
P0348 and P0021 may involve the same Bank 2 intake camshaft, but the codes identify different problems.
P0348 indicates excessive voltage in the Bank 2 Camshaft Position Sensor “A” circuit.
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 condition
- VVT-solenoid operation
- Camshaft-phaser performance
- Oil pressure
- Mechanical timing
- Timing-chain wear
P0348 should remain focused on:
- Sensor supply voltage
- Sensor ground
- Signal voltage
- Shorts to voltage
- Open circuits
- Connector terminals
- ECM input testing
If both codes appear, repair the P0348 electrical problem first. The ECM cannot accurately judge camshaft timing when the position signal is stuck at an incorrect voltage.
How Camshaft Position Sensors Work
Camshaft position sensors generally use Hall-effect or magnetic designs.
Hall-Effect Sensors
A Hall-effect camshaft sensor usually has three circuits:
- Power supply
- Ground
- Signal
As the camshaft trigger wheel passes the sensor, the signal switches between high and low voltage states. An oscilloscope normally displays a digital square wave.
A Hall-effect sensor may set P0348 if:
- The signal wire contacts the supply circuit
- The signal wire contacts battery voltage
- The sensor ground opens
- The sensor fails internally
- The signal cannot switch low
- An open circuit leaves the ECM pull-up voltage high
Magnetic Sensors
A magnetic or variable-reluctance sensor typically generates alternating voltage as the reluctor passes its magnetic core.
Its signal changes with:
- Camshaft speed
- Sensor air gap
- Reluctor condition
- Sensor condition
- Circuit resistance
A magnetic sensor is more commonly associated with weak signals, missing output or waveform problems. However, a wiring short or incorrect circuit connection may still cause a high-input code.
Confirm the sensor design before applying voltage or interpreting test results.
How to Diagnose the P0348 Code
1. Scan Every Control Module
Retrieve all stored, pending and permanent trouble codes.
Record related codes involving:
- Bank 1 camshaft position
- Bank 2 camshaft position
- Crankshaft position
- System voltage
- Sensor-reference voltage
- Variable valve timing
- Camshaft timing
- Misfires
Multiple circuit-high codes may indicate a shared ground fault, charging-system problem or harness short rather than several failed sensors.
Save the freeze-frame data before clearing anything. Important information includes:
- Engine speed
- Battery voltage
- Coolant temperature
- Vehicle speed
- Engine load
- Time since startup
If P0348 appeared when charging voltage was abnormally high, test the charging system before blaming the sensor.
2. Check Battery and Charging Voltage
Measure voltage:
- With the engine off
- During cranking
- At idle
- With electrical accessories operating
- At approximately 2,000 RPM
An overcharging alternator may raise system voltage enough to affect multiple sensor circuits.
Inspect:
- Battery terminals
- Engine grounds
- Chassis grounds
- ECM grounds
- Alternator connections
If several unrelated high-input codes appear together, system voltage and shared grounds deserve immediate attention.
3. Confirm Bank 2 Sensor “A”
Use reliable service information to identify:
- Cylinder number one
- Bank 2
- Sensor “A”
- Intake camshaft
- Correct sensor connector
- Terminal assignments
- Expected voltage values
Don’t rely on a generic engine diagram or assume Bank 2 is always on a particular side.
4. Inspect the Sensor Connector
Disconnect the Bank 2 Sensor “A” connector and inspect it closely.
Look for:
- Bent terminals
- Recessed pins
- Spread female terminals
- Broken connector locks
- Corrosion
- Oil contamination
- Water intrusion
- Damaged seals
- Melted plastic
- Incorrectly installed terminals
- Previous connector repairs
Check terminal tension using the correct test probe. A terminal may appear normal but fail to grip the sensor pin securely.
If the connector has been replaced, verify that every wire is installed in the correct cavity. Crossing the supply and signal wires can produce a very reliable high-voltage problem.
5. Inspect the Wiring Harness
Trace the harness between the sensor and ECM where possible.
Pay close attention to wiring near:
- Exhaust manifolds
- Cylinder heads
- Valve covers
- Timing covers
- Intake-manifold brackets
- Engine mounts
- Harness retainers
- Previous repair areas
- Aftermarket accessories
Look for wiring that is:
- Melted
- Crushed
- Stretched
- Pinched
- Rubbed through
- Spliced incorrectly
- Contacting another powered circuit
A damaged signal wire touching a supply wire can hold the camshaft signal high.
Move the harness while monitoring signal voltage or scan data. A change in voltage may reveal an internal wire break or intermittent short.
6. Identify the Correct Circuits
Consult the wiring diagram before probing the connector.
A typical Hall-effect sensor has:
- Supply voltage
- Ground
- Signal return
However, voltage values and terminal positions vary.
Possible supply voltages include:
- Five volts
- Eight volts
- Battery voltage
- Manufacturer-specific regulated voltage
Never assume a terminal’s function based only on wire color. Manufacturers reuse colors with enthusiasm bordering on performance art.
7. Test the Sensor Ground
An open or high-resistance ground is one of the most important P0348 causes.
With the sensor connected and operating, measure voltage drop between the sensor ground terminal and battery negative.
A poor ground may allow the sensor’s signal voltage to remain high because the circuit cannot switch or return low correctly.
Check for:
- Open ground wire
- Corroded ground splice
- Loose engine ground
- Damaged ECM ground
- Spread connector terminal
- Excessive resistance under load
A continuity test may show that the ground is technically connected while missing the fact that it cannot carry current reliably. Voltage-drop testing is more useful.
8. Check the Signal Circuit for a Short to Voltage
Disconnect the sensor and ECM as required by the manufacturer’s procedure.
Test the signal circuit for:
- Short to battery voltage
- Short to sensor supply voltage
- Short to another powered circuit
- Excessive resistance
- Open circuit
- Correct continuity between the sensor and ECM
If voltage remains on the signal wire with both ends disconnected, the wire is contacting another voltage source somewhere in the harness.
Do not use a powered test light on an ECM signal circuit unless the manufacturer specifically permits it. Modern modules tend to object when test equipment introduces battery voltage where it doesn’t belong.
9. Observe the Signal With the Sensor Disconnected
Measure the signal-circuit voltage with the ignition on and the sensor unplugged.
Interpretation depends on the circuit:
- If the voltage remains at an expected pull-up value, the circuit may be operating normally while disconnected.
- If the voltage equals battery voltage when only a lower pull-up voltage is specified, suspect a short to battery power.
- If reconnecting the sensor doesn’t change the signal, suspect the sensor, ground circuit or connector.
- If unplugging the sensor causes the voltage to return to normal, the sensor may be internally shorted.
Consult manufacturer specifications before judging the result. A disconnected five-volt reading may be normal on one circuit and evidence of a fault on another.
10. Compare Bank 1 and Bank 2
If the engine uses matching sensors, compare the Bank 2 circuit with the equivalent Bank 1 circuit.
Compare:
- Supply voltage
- Ground voltage drop
- Key-on signal voltage
- Cranking signal
- Running waveform
- Signal frequency
- High and low voltage levels
If Bank 1 switches normally while Bank 2 remains high, concentrate on the Bank 2 sensor, connector, wiring and ECM terminal.
Do not swap sensors unless both part numbers and installation dimensions are identical and the service procedure allows it.
11. Test the Sensor Signal
Back-probe the signal circuit without damaging the connector or weather seal.
For a Hall-effect sensor, verify that the signal switches cleanly between its specified high and low states.
A properly operating signal should not remain at one fixed voltage while the camshaft rotates.
Possible findings include:
- Signal stuck at supply voltage
- Signal unable to switch low
- Correct signal at the sensor but high voltage at the ECM
- Signal returning to normal when the connector is moved
- Proper cold operation followed by high voltage when hot
If supply and ground are correct but the sensor cannot generate the expected waveform, replace the sensor with a quality component.
12. Use an Oscilloscope
An oscilloscope provides the clearest view of camshaft-sensor operation.
Look for:
- Signal permanently stuck high
- Missing low transitions
- Incorrect high-state voltage
- Electrical noise
- Distorted pulse width
- Missing pulses
- Voltage increasing with temperature
- Waveform changes during a harness wiggle test
Compare the Bank 2 Sensor “A” waveform with:
- Bank 1 Sensor “A”
- Crankshaft-position signal
- Known-good waveform
- Manufacturer specifications
A multimeter may display an average voltage that looks reasonable while the actual waveform is unusable. Electricity enjoys technical loopholes.
13. Check the Sensor and Reluctor
Inspect the sensor if electrical testing doesn’t reveal an external short or ground problem.
Look for:
- Cracked sensor housing
- Damaged sensing tip
- Metal debris
- Incorrect part number
- Improper installation
- Damaged O-ring
- Sensor not fully seated
- Excessive air gap
Inspect the reluctor or trigger wheel when accessible.
Check for:
- Bent teeth
- Missing trigger segments
- Excessive runout
- Loose reluctor
- Incorrect installation
- Debris
- Camshaft end play
Reluctor problems are more likely to produce irregular waveforms or performance codes than a fixed circuit-high condition. Keep that distinction in mind before dismantling the timing system.
14. Test the ECM Last
Suspect the ECM only after confirming:
- Correct sensor supply voltage
- Reliable sensor ground
- No short to battery voltage
- No short to sensor supply
- Correct signal-wire continuity
- Proper sensor operation
- Correct terminal tension
- Proper waveform at the sensor
- Incorrect voltage at the ECM input
If the waveform is correct at the sensor but incorrect at the ECM, repair the wiring or connector between them.
If the correct waveform reaches the ECM and P0348 still returns, check technical service information for software updates before replacing the module.
ECM replacement may require programming, immobilizer setup or security relearning. It should remain the final diagnosis, not the expensive opening guess.
Common P0348 Diagnostic Mistakes
Avoid these common mistakes:
- Replacing the sensor without measuring the signal voltage
- Confusing Bank 1 with Bank 2
- Testing the exhaust sensor instead of Sensor “A”
- Assuming every sensor uses a five-volt supply
- Ignoring an open sensor ground
- Missing a signal wire shorted to battery voltage
- Overlooking crossed wires after connector replacement
- Using only a resistance test
- Failing to inspect connector terminal tension
- Ignoring charging-system overvoltage
- Treating P0348 as a timing-chain code
- Replacing a VVT solenoid for a sensor circuit-high fault
- Replacing the ECM before checking the complete circuit
“Circuit high” doesn’t mean the sensor is located too high on the engine, nor does it mean the camshaft is over-advanced. It means the monitored electrical voltage is above the ECM’s acceptable range.
How Do You Fix the P0348 Code?
The correct repair depends on the confirmed cause.
Possible repairs include:
- Repairing a signal wire shorted to battery voltage
- Repairing a signal wire shorted to sensor supply
- Repairing an open or high-resistance sensor ground
- Replacing damaged connector terminals
- Correcting crossed connector wiring
- Cleaning corrosion or oil contamination
- Repairing melted or chafed wiring
- Rerouting the harness away from heat
- Repairing engine or ECM grounds
- Replacing Bank 2 Camshaft Position Sensor “A”
- Installing the correct OEM-quality sensor
- Correcting sensor installation
- Repairing a charging-system overvoltage condition
- Updating ECM software
- Replacing and programming the ECM when testing confirms failure
After completing the repair:
- Clear stored codes.
- Start the engine several times.
- Monitor Bank 2 camshaft-position data.
- Confirm that the signal switches correctly.
- Complete the required drive cycle.
- Rescan for pending and permanent codes.
- Reproduce the original conditions shown in the freeze-frame data.
P0348 Repair Costs
Repair costs vary by vehicle, accessibility and the actual fault.
| Repair | Estimated cost |
| Diagnostic inspection | $100–$250 |
| Clean or secure connector | $50–$150 |
| Replace sensor connector | $100–$350 |
| Repair damaged wiring | $100–$700 |
| Repair engine or ECM ground | $100–$500 |
| Replace camshaft position sensor | $150–$500 |
| Repair charging system | $200–$1,200 |
| Repair engine wiring harness | $400–$2,500+ |
| ECM software update | $100–$300 |
| Replace and program ECM | $800–$2,500+ |
These are general estimates. Labor costs increase when the sensor harness disappears beneath an intake manifold, behind a cylinder head or into whichever location offered the least access to an adult human hand.
Can You Drive With a P0348 Code?
Limited driving may be possible if:
- The engine starts normally
- It runs smoothly
- It doesn’t stall
- The Check Engine Light remains steady
- No correlation codes are present
- There is no timing-system noise
Stop driving if:
- The engine stalls
- The vehicle becomes difficult to restart
- Severe hesitation develops
- The engine misfires heavily
- The Check Engine Light flashes
- The vehicle enters reduced-power mode
- Acceleration becomes unsafe
- An oil-pressure warning appears
A circuit short may worsen as the harness moves or heats up. Diagnose the fault before trusting the vehicle for extended driving.
P0348 Frequently Asked Questions
Does P0348 mean the camshaft position sensor is bad?
Not necessarily. A failed sensor can cause P0348, but so can a short to voltage, open sensor ground, damaged connector, crossed wiring or failed ECM input.
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 refers to the intake camshaft sensor. Verify the location using vehicle-specific service information.
What voltage is too high for a camshaft sensor?
The threshold depends on the vehicle and circuit design. Compare measured voltage with the manufacturer’s specification rather than using one universal value.
Can an open ground cause P0348?
Yes. If the sensor loses its ground, its signal may remain high or become unable to switch low.
Can a broken signal wire cause P0348?
Yes. On circuits using an ECM pull-up resistor, an open signal wire may leave the ECM input at a high voltage and trigger P0348.
Can a bad alternator cause P0348?
An overcharging alternator can affect sensor and module voltages, especially if several circuit-high codes appear together. Test charging voltage before replacing multiple sensors.
Can dirty oil cause P0348?
Dirty oil is more likely to cause VVT performance or camshaft-timing codes. It doesn’t normally create a direct circuit-high fault.
Can a timing chain cause P0348?
A stretched chain generally causes correlation or timing-performance codes rather than a direct circuit-high code. P0348 should be diagnosed electrically first.
Can I test the sensor with a multimeter?
A multimeter can check supply voltage, ground voltage drop and basic signal voltage. An oscilloscope is better for verifying whether the signal switches correctly.
Should I replace both camshaft sensors?
No. Replace only the component proven defective unless both sensors fail testing or the manufacturer recommends replacing them together.
Will clearing the code fix P0348?
No. Clearing the code only removes it temporarily. P0348 will return if the high-voltage condition remains.
Final Thoughts
P0348 means the Bank 2 Camshaft Position Sensor “A” circuit voltage is above the range expected by the ECM.
Begin by scanning for related codes, checking charging voltage and confirming the location of Bank 2 Sensor “A.” Inspect the connector and wiring, then test the sensor supply, ground and signal circuits.
Pay particular attention to an open ground, crossed connector wiring and a signal wire shorted to battery or sensor-supply voltage. Compare Bank 2 operation with Bank 1 and use an oscilloscope to verify that the signal switches between its expected high and low states.
Replace the sensor only after confirming that its power, ground and external wiring are correct. Test the ECM last.
For additional diagnostic coverage, visit the complete P-series OBD-II code guide, browse the OBDII Doctor archive or use the Car Symptoms Encyclopedia to diagnose the vehicle’s actual behavior.
P0348 says the voltage is too high. Fortunately, the repair bill doesn’t have to follow it—assuming someone tests the wiring before purchasing everything connected to it.
