- Vehicles
- Cars
P0340
P0340 (generic OBD-II): camshaft position sensor circuit, bank 1
Risk level
Medium
Proceed carefully and stop if the check is unclear.
Urgency
High
Quick answer
The engine computer gets no valid signal from the bank 1 intake camshaft position sensor. Note whether the car starts worse or hesitates, and save the codes without clearing them before going to the workshop.
Safety first
Stop and check this first
- If the engine stalls with this code, avoid fast roads until it is checked; a stall while moving leaves you without acceleration.
Safe checks you can perform
- Symptoms when starting and driving
- Camshaft, crankshaft and timing codes
Leave these tasks to a qualified professional
- Do not attempt this professional task: Camshaft signal against crankshaft
- Do not attempt this professional task: Verification with no pending codes
What a technician must be able to justify
Technician visit
These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.
These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.
Camshaft signal against crankshaft
What they doThe technician views the camshaft sensor signal alongside the crankshaft signal on an oscilloscope and measures supply and ground at the connector.
They must show youthe capture of both signals and the values measured at the connector.
In writingthe cause found and the part or repair applied.
Verification with no pending codes
What they doAfter the repair, the technician starts the engine several times cold and hot and checks no code is pending.
They must show youthe code reading after several starts.
In writingthe test conditions and that no code was left pending.
Before accepting a part or repair
Nothing has been shown yet. Do not accept a part swap based on the code alone.
Follow these steps
Note: Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.
Symptoms when starting and driving
- Who:
- you.
- How:
- note whether the engine takes longer to start, stalls or hesitates, and under what conditions (cold, hot, after rain).
- Result that matters:
- whether there are driving symptoms besides the light.
- If it stalls or starts with difficulty:
- avoid long trips; book an inspection soon and explain when it happens.
- If you notice nothing:
- still note the code; it may be an intermittent circuit fault.
- Evidence to keep:
- a note with the date, engine temperature and symptom for each episode.
Do not keep driving if the engine stalls while moving; have it taken to a workshop.
Evidence: Ford 2020-2023 gasoline OBD system operation
Camshaft, crankshaft and timing codes
- Who:
- you, with the car parked and a generic OBD-II reader plugged into the diagnostic socket.
- How:
- read all codes and save the P0340 freeze frame.
- Result that matters:
- whether crankshaft (P0335), correlation (P0016) or variable timing codes appear.
- If there are crankshaft or correlation codes:
- tell the workshop, because it changes the order of diagnosis.
- If P0340 is alone:
- the workshop should measure the camshaft sensor circuit.
- Evidence to keep:
- a photo of the codes and the freeze frame.
Use the reader only with the car stopped. Do not press the clear option: under the OBD rules the freeze frame is erased together with the code.
Evidence: Ford 2020-2023 gasoline OBD system operation · Title 13, California Code Regulations, Section 1968.2, Malfunction and Diagnostic System Requirements (OBD II)
Still not solved
If the error persists, stop here. See what the technician must do and show you.
Where this code applies
A code is meaningful only inside the right product and version context.
Primary scope
- System
- Vehicles
- Brand
- OBD-II genérico
- Product type
- Cars
Known code variants
- P0340
- P0340 camshaft position sensor
- P0340 OBD2
- P0340 sensor árbol de levas
What it means
P0340 is the generic code for camshaft position sensor circuit, bank 1; in Ford's documentation it is the intake camshaft. The computer watches it continuously alongside the crankshaft sensor to synchronise ignition and injection. The signal can go missing because of the sensor, its wiring or connector, its supply or a problem with the wheel it reads. The code describes the circuit, not the failed part.
Warnings and stop conditions
- Mediumeditorial warning
If the engine stalls with this code, avoid fast roads until it is checked; a stall while moving leaves you without acceleration.
Evidence: Ford 2020-2023 gasoline OBD system operation
Symptoms and causes
Probable causes · in order
- Wiring or connectorPossible
A chafed wire or corroded connector cuts the signal intermittently. Suspect it if the code comes and goes.
Evidence: Ford 2020-2023 gasoline OBD system operation
- Camshaft sensorPossible
The sensor itself may stop giving a signal. It is confirmed by viewing its signal on an oscilloscope against the crankshaft signal.
Evidence: Ford 2020-2023 gasoline OBD system operation
- Shared supplyPossible
If codes from other sensors appear at the same time, the cause may be a common supply or ground.
Evidence: Ford 2020-2023 gasoline OBD system operation
Virtual technician
Does P0340 still appear after these checks?
Answer a few questions to narrow down the likely cause and the safest next action. Guidance only - it never replaces a professional.
Sources and technical references
- 1
Ford 2020-2023 gasoline OBD system operation
Ford Motor Company · 2023 · manual
- 2
California Air Resources Board · 2006 · official_doc
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