P0343: Camshaft Position Sensor A Circuit High Bank 1 or Single Sensor

P0343 means the signal of the intake camshaft sensor of bank 1 (or the only cam sensor) stays at supply level without edges. Causes are a signal wire shorted to positive, an open signal wire that the module's pull-up holds at 5 V, a broken sensor ground or a faulty sensor. Ford's 2023 diesel sets it when the signal stays at system voltage over 10 or more crank revolutions (3 s). On the Saab 9-4X V6 (GM LAU) the signal must stay high without pulses for more than 1 s, or 10 s cumulatively, and the code follows after two trips. Saab's Motronic 2.8.1 (900 V6) treats low and high together and allows an air gap of at most 1.5 mm. The consequences are as for P0340: longer cranking, cam timing switched off, loss of power.

Bank 1 is the side of the engine with cylinder 1. Inline engines only have this bank.

Symptoms

• Check engine light on
• Longer cranking before the engine starts
• Loss of power (cam timing held in its base position)
• Rough idle, occasionally stalling

Most likely causes

• Signal wire open or shorted to positive
• Sensor ground open
• Camshaft position sensor faulty
• Connector corroded

What to check, in order

Start with the simplest. You can tick off each step.

1. Check the connector and look for metal filings on the sensor
2. Check the sensor's ground and make sure the signal wire is not receiving voltage from another circuit.
3. See whether there is an RPM signal while cranking
4. Measure the signal with an oscilloscope if you can
5. Check the engine timing before replacing expensive parts

Good to know

• Repair difficulty: easy
• It can trigger limp mode.
• It affects emissions.

What each character of P0343 means

• P: Powertrain: engine and transmission
• 0: Generic code: same on every make
• 3: Ignition and misfires
• 43: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0343?

Avoid driving: the engine can stall while moving. If the timing is off, continuing can cause serious damage.

What causes code P0343?

The most common causes are: signal wire open or shorted to positive; sensor ground open; camshaft position sensor faulty.

Related codes

• P0340Camshaft Position Sensor A Circuit Bank 1 or Single Sensor
• P0342Camshaft Position Sensor A Circuit Low Bank 1 or Single Sensor
• P0348Camshaft Position Sensor A Circuit High Bank 2
• P0368Camshaft Position Sensor B Circuit High Bank 1

Sources

• fordservicecontent.com: obd summary diesel 2023
• saabwisonline.com: dtc p0341 p0342 p0343 p0346 p0347 p0348 p0366 p036
• saabwisonline.com: p0342p0343
• law.cornell.edu: 13 CCR 1968.2

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.