Timing and crank/cam sensorsGeneric OBD-II codeUrgency: Garage soon
Code P0343: camshaft sensor: high signal
P0343 means: camshaft position sensor "A" circuit: high signal (bank 1 or single sensor).[1][2][3] The ECU registers too high a voltage in the camshaft sensor "A" circuit, outside the manufacturer's parameters. This sensor tells the ECU the camshaft position so it can regulate injection and mixture.[1][3]
What code P0343 means
The ECU registers too high a voltage in the camshaft sensor "A" circuit, outside the manufacturer's parameters. This sensor tells the ECU the camshaft position so it can regulate injection and mixture.[1][3]
According to DTCSearch, under a General Motors standard the code is set with the engine below 4000 rpm when the sensor pulse stays high. It is a generic code (P0), with the same definition on all makes.[2][4]
Original definition (SAE J2012): Camshaft Position Sensor "A" Circuit High (Bank 1 or Single Sensor)[1][2][3]
Causes of P0343
From most to least likely, according to the sources.
Symptoms
- Engine warning light on.[1][3]Engine warning light: faults that cause it
- Uneven idle, jerking and roughness.[1][3]Vibrations: faults that cause it
- Difficulty starting or an engine that will not start.[1][3]Hard to start: faults that cause it
- Increased fuel consumption.[1][3]Uses more fuel: faults that cause it
- Engine stalling, sometimes temporary.[1][3]Engine stalls: faults that cause it
How to diagnose P0343
In order: from the most likely and cheapest to check to the most expensive.
- 1Check whether other codes are stored and deal first with any related to the sensor or the crankshaft.[1][5]
- 2Inspect the sensor: if it is oily or wet, fix the leak first and then clean or replace the sensor.[1]
- 3Measure the battery voltage and check the condition of the starter before condemning the sensor.[1]
- 4Inspect the sensor's wiring and connectors and measure supply, ground and signal.[1][5]
- 5If everything above is fine, replace the sensor with a quality one and, only as a last resort, suspect the ECU.[1][5]
Can I keep driving with P0343?
Garage soon
Mechanic Base rates it medium severity: the car can keep running while it works, but jerking or stalling can appear without warning and make it unwise to carry on using it normally.[1]
Documented faults related to P0343
Known faults of specific engines and cars, with their repair cost, the affected years and their sources.
Engine sensors: the most serious faults by engine and car
- High severityFrequency: Occasional2.0 DTI and 2.2 DTIVP44 injection pump and air mass meter failureGerman Wikipedia documents recurring failures of the Bosch VP44 injection pump and the air mass meter in the early years of this engine. An owner testimony for this engine describes the pump being replaced at 192,500 km, at a cost the owner calls «prohibitive».
- Medium severityFrequency: Common2.0 TDIClogged particulate filter or faulty pressure sensorThe 2.0 TDI's particulate filter clogs if the car mostly makes short journeys, because it never gets to regenerate; sometimes the fault is just the differential pressure sensor. Cleaning it costs around €200 and replacing it, €800 to €3,000.Repair (garage): €800–€3,000
- Medium severityFrequency: Common1.4 and 1.6 8vCrankshaft position sensor failure (TDC sensor)The crankshaft position sensor (capteur PMH, or TDC sensor) appears repeatedly in the reliability sources for the Clio II, the Kangoo I and the Dacia Logan I with this engine, with hard cold starting or stalling as the main symptoms. It is a cheap part, but the failure can leave you stranded.
- Medium severityFrequency: Common1.4 and 1.6 16vCrankshaft position sensor failureThe crankshaft position sensor (capteur PMH) appears repeatedly in the reliability sources for almost every generation with this engine, with hard cold starting, stalling or the car cutting out unexpectedly. It is a cheap part, but the failure can leave you stranded.
Wiring, connectors and short circuits: the most serious faults by engine and car
- Critical severityFrequency: OccasionalBMW N62 / N63Additional turbo coolant pump with a risk of short circuit and fireIn 2011 BMW recalled 5, 6 and 7 Series, X5 and X6 models built between 2007 and 2011 because of the additional turbo coolant pump: moisture, a short circuit and, in extreme cases, a fire. In 2012 there was another campaign for a crack in the pump, with a more robust version.
- High severityFrequency: Occasional1.3 TCeBlown fuel pump fuseOn the Renault Captur II and Clio V with the 1.3 TCe engine, a 20-amp fuse can blow and leave the car without an engine. According to L'argus, in April 2021 this fault still had no factory fix; the official service centre's diagnosis includes checking, and sometimes replacing, the catalytic converter.
- High severityFrequency: OccasionalM264/M254Poorly tightened 48 V earth wiring in the mild-hybrid system (fire risk)Mercedes-Benz has issued several recalls (2022-2025) because the 12 V and 48 V earth connections of some cars with a 48 V system may be poorly tightened: resistance rises, the connection heats up and a fire cannot be ruled out. The official workshop checks them and repairs them if necessary in an hour or more.
- High severityFrequency: Occasional1.9 TDIUnit injector tappet wear and injector wiring damageOn the unit injector system, the tappets that operate the injectors can wear if the oil is not changed on time, and the injector wiring can be damaged by contact with oil, causing misfires or loss of power.
- Critical severityFrequency: CommonRover 75Seat SRS connector fault with airbag and seatbelt warning light onAuto Express warns that the Rover 75's seat SRS connector can cause the airbags to fail, and dealers were fixing it with revised connectors. The Dutch APK inspection puts the airbag or seatbelt fault warning among the most frequent defects across almost all series.
- Critical severityFrequency: OccasionalAlfa Romeo GiuliettaShort circuit from badly routed wiring that can prevent gear shifting (KBA campaign, 2010-2015)Yes: according to Germany's KBA, on Alfa Romeo Giulietta cars built between 2010 and 2015 inadequate cable routing could cause a short circuit and, as a result, gear-shift failure.
Frequently asked questions
What does code P0343 mean?
The signal from camshaft sensor "A" (bank 1 or single sensor) is too high. The cause is usually the sensor or its wiring.[1][2]
Can I keep driving with P0343?
If the car keeps running you can get to the garage, but carrying on driving is not recommended: jerking or stalling can appear at any moment.[1]
Can a battery problem cause P0343?
Yes, according to Mechanic Base a weak battery or a worn starter motor are among the possible causes, so check them before replacing the sensor.[1]
What is the difference from P0342?
They affect the same sensor, but P0343 indicates a high signal and P0342 a low signal.[2][3]
Will I pass the MOT with code P0343?
If the code has switched on the engine warning light, no: with that light on, the inspection records a serious defect, and on Euro 5 and Euro 6 cars the ITV (Spain's roadworthiness inspection, similar to the MOT) also reads the OBD diagnostic system. Repair the fault before you go; clearing the code just before the inspection does not help either, because it counts as a serious defect.[6]
Not sure what is wrong with your car? Describe what you notice in the symptom diagnosis or see all fault codes.
Sources
Every fact on this page links to its source. If you find an error, let us know.
- P0343 Code – Meaning, Causes & How to fix itMechanic Base · Technical documentation · consulted 29 October 2026
- p0343 DTC: Camshaft Position Sensor "A" Circuit HighDTCSearch · Technical documentation · consulted 29 October 2026
- P0343 – Camshaft Position Sensor "A" Circuit High Input (Bank 1)AutoDTCs · Technical documentation · consulted 29 October 2026
- On-board diagnosticsWikipedia · Other source · consulted 29 October 2026
- How to Test Crankshaft and Camshaft Position SensorsAutoDTCs · Technical documentation · consulted 29 October 2026
- Desmontando mitos: ¿puede pasar mi coche la ITV con el testigo de «avería motor» encendido?Diariomotor · Motoring press · published 8 March 2021 · consulted 2 October 2026 · in Spanish