Cam sensor signal below expected voltage.
P0342 — also written PO342, P 0342, 0342 — is the OBD-II code for camshaft position sensor a low input (bank 1). Same code, same fix: this page covers every spelling of it.
This code means the ECU isn't hearing back from the camshaft sensor properly, usually because the sensor's internal coil has packed up or the wiring's taken a beating. It's a classic headache on Vauxhall Corsas and older BMWs where the heat cooks the plastics.
P0342 is a sensors fault code, typically costing £90–£400 to put right in a UK garage.
What P0342 actually feels like to drive
- The car takes ages to fire up—you're cranking it for 5-10 seconds before it coughs into life.
- Engine suddenly cuts out while you're waiting at a roundabout or traffic lights.
- Noticeable loss of 'oomph' when overtaking, like the turbo isn't quite waking up.
- The car runs perfectly fine once it's started, but the EML light is staring you in the face.
- A weird 'stumble' or hesitation just as you pull away from a junction.
What causes P0342?
- Failed sensor
- Wiring short
- Damaged reluctor on cam
UK vehicles that throw P0342 most often
- Vauxhall Corsa D/E 1.2 & 1.4 (A12XER/A14XER) 2009-2017
- BMW 3 Series (E46/E90) 318i/320i N42/N46 engines
- Mini Cooper (R56) 1.6 N12/N14 engines 2006-2013
- Hyundai i10/i20 1.2 Kappa engines 2008-2015
- Chevrolet Aveo 1.2/1.4 Petrol 2008-2011
- Volkswagen Golf Mk5/Mk6 1.4 TSI (Cava/Cave) 2008-2014
How P0342 is fixed
- Replace cam sensor
- Inspect cam gear tone ring
The P0342 misdiagnosis that wastes money
I’ve lost count of how many people waste £15 on a 'cheap as chips' sensor from eBay or Amazon, only to find the P0342 stays exactly where it is. Because the code says 'Low Input,' folks assume the sensor is dead. In reality, I often find a frayed wire in the loom near the cylinder head heat shield, or worse, a stretched timing chain on those Vauxhall 1.2 engines. If the chain's gone slack, the timing drifts, and the ECU gets a weak or late signal it interprets as a voltage fault. Check your oil level first—low oil pressure on a hydraulic tensioner causes half these 'sensor' faults.
What a UK garage should charge for P0342
For a basic sensor swap on something like a Corsa, you're looking at about £50 for a decent Bosch sensor and £40 labour—call it £90-£100 total. However, if I have to spend an hour chasing a break in the loom or if it's a BMW where the sensor is buried under the intake, you'll be north of £200. If the P0342 is actually caused by a stretched timing chain (common on the TSI and VTi engines), you're looking at a £600 to £800 bill for a full chain kit. Main dealers will easily double these prices just for the 'prestige' of the stamp.
P0342 repair cost in the UK
Most P0342 repairs land between £90–£400 including parts and labour. The spread is wide because the cheap fix (a sensor, a hose, a leak) and the expensive fix (a major component) throw the same code — which is why a proper diagnosis before parts are bought saves the most money.
Bob's tip on P0342
Don't let a garage just 'swap and hope.' If they tell you it needs a sensor, ask them: "Have you checked the signal with a scope, or just read the code?" A proper tech will back-probe the connector to see if the 5V reference is actually reaching the sensor. If you're driving a Vauxhall or a Mini, ask them to check the timing chain slack while the rocker cover is off. To save cash, ask for a Bosch or Delphi sensor—they're the same as the 'Genuine' ones in the fancy manufacturer box but usually half the price at the local Euro Car Parts counter.
Can you drive with P0342?
Yes but may cut out.
Urgency: medium.