P0348
PowertrainCamshaft Position Sensor A Circuit High Input (Bank 2)
The camshaft position sensor on bank 2 is feeding the ECU a voltage that's sitting too high, so the module can't trust what the camshaft is doing on that side. For you, that usually shows up as a rough-running engine and a warning light, and the engine may drop into limp mode to protect itself. On a V6 or V8 this is bank 2 only, so the fault is on one cylinder bank rather than the whole engine.
ⓘ Information only. This page provides general educational information about fault code P0348. We do not assess the urgency or safety implications of any specific fault. That requires in-person diagnosis by a qualified mechanic. Full terms.
Recommended next steps
Whether a fault is urgent, drivable, or routine depends entirely on the cause on a specific vehicle, and that can only be determined by a qualified mechanic with diagnostic equipment. If a warning light is illuminated, the most reliable next step is professional diagnosis.
What does P0348 mean?
P0348 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Camshaft Position Sensor A Circuit High Input (Bank 2).
This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.
Symptoms commonly associated with this code
Symptoms that drivers often report alongside this code. Not all may apply to every case:
- • Engine management light on, sometimes the first and only sign
- • Lumpy idle, more obvious when the car's sat at a junction or warming up
- • Flat spot or hesitation when you put your foot down
- • Occasional stalling, usually cold or crawling along in traffic
- • Down on power, the engine feels like it's holding back
- • Slow or awkward starting on some engines, particularly first thing in the morning
Possible causes
Causes commonly associated with P0348, listed in approximate order of typical investigation. The actual cause on a specific vehicle can only be confirmed by professional diagnosis.
- 1. The cam sensor itself failing internally and pushing out a high voltage. This is the usual culprit, sensors do wear out with heat and miles
- 2. Wiring to the sensor damaged, chafed, or shorted to a power feed, which is exactly what drives the signal high
- 3. Corroded or oil-soaked connector at the sensor, very common where a cam seal has been weeping onto the plug
- 4. A poor earth or supply in the harness throwing the reference voltage off
- 5. Engine oil leaking down into the sensor bore on some designs, gumming up the tip
- 6. ECM fault, which is rare and only worth considering once everything else checks out clean
How mechanics typically diagnose
A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training.
- 1. Plug in a scanner and confirm P0348 is current, not just stored, and note any cam or crank codes sitting alongside it
- 2. Get to the bank 2 sensor connector and check it properly, look for green corrosion, spread pins, or oil tracking into the plug
- 3. Back-probe the sensor's signal and supply wires with a multimeter, engine running, and compare against the manual figure. A signal pinned high points at the sensor or a short to power
- 4. Wiggle-test the harness from the connector back toward the loom while watching live data, since intermittent high readings are often a chafed wire
- 5. Check the crank sensor and its wiring too, the ECU cross-references the two and a crank issue can muddy the picture
- 6. Clear the code and road-test, then recheck. If it comes straight back with the engine settled, you've narrowed it to a hard fault rather than a glitch
Common questions about P0348
Can I keep driving for a bit or do I need to sort it now? +
Short hops are usually fine if the engine's still running cleanly, but don't ignore it. With dodgy cam timing data the engine can stall on you without warning, and if it slips into limp mode you'll have no real power for overtaking on the motorway. If it's idling rough or stalling repeatedly, get it looked at before you do a long trip.
Is it the sensor that's gone or is it the wiring? +
A high-input code like P0348 points at the wiring side more often than a plain sensor failure, because the classic cause of a signal reading high is a short to a power feed or a corroded connector. Always inspect the plug and harness before you throw a sensor at it. That said, the sensor itself does fail too, so the smart move is to test the voltage at the connector first and let the readings tell you which it is.
How long should the repair take? +
If it's just the sensor and it's easy to reach, a competent garage will have it done in well under an hour. Rear-bank sensors tucked behind the engine, or a wiring repair where they've got to trace and splice a damaged loom, can run to a couple of hours of labour. Diagnosis itself is usually billed as a separate half-hour to hour on top.
Is a cheap aftermarket sensor worth it or should I stick with genuine? +
A decent branded aftermarket sensor from the likes of Bosch, Delphi, or Hella is fine and a fraction of dealer money. Where people come unstuck is the bargain-bin no-name parts off eBay, which can read out of spec from new and have you back chasing the same code. Match the connector and the part number for your engine, and steer clear of the cheapest listings.
Information only, not professional advice
The information on this page is provided for general guidance and educational purposes only. It is not a substitute for diagnosis or repair advice from a qualified mechanic. Always verify any fault before paying for repairs. carfaultcodes.co.uk accepts no liability for decisions made based on this information. Full terms →