P0340 – Camshaft position sensor A circuit – bank 1

P0340 reports a circuit problem for camshaft-position sensor A on bank 1, or the single sensor where applicable. The problem can concern the sensor, its connection or the signal being detected.

Powertrain · Camshaft-position signal

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Meaning and affected system

The engine controller combines camshaft and crankshaft information to identify engine phase. An unusable camshaft signal affects that information. The A designation must be matched to the correct sensor using engine documentation.

Possible causes

Broken or damaged wiring and poor connector contact are possibilities.
A sensor fault or damage to its target wheel can also contribute.
Several electrical codes together can indicate a shared area of wiring that needs investigation.

Possible symptoms

Starting difficulties or a fallback engine-control mode may occur.
The check engine light may appear; the actual effect depends on the engine.

Useful diagnostic considerations

Establish the sensor location and terminal assignments from the vehicle documentation.
Have wiring, contacts, supply and signal checked using appropriate equipment.
If P0016 is also present, assess signal quality and timing relationship together.

What this code does not prove

P0340 describes the sensor circuit; P0016 describes the crankshaft-to-camshaft relationship. A new sensor cannot repair damaged wiring or incorrect mechanical timing.

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Sources and interpretation

This explanation was editorially cross-checked against the technical sources below. Manufacturer documents concern particular vehicle applications; their thresholds and repair procedures must not be applied universally.

OBD-II code data: OBDex (CC0 1.0) · 196fddffb6ef

Editorial source review: 16 October 2026.

The causes listed are possibilities without a likelihood ranking. This page cannot replace diagnosis of the vehicle. A code alone confirms neither a failed component nor that continuing to drive is safe. The actual condition, warnings, handbook and applicable manufacturer diagnostics determine the next step.