System: Powertrain (P-Code) Coverage: SAE Standard (Generic) Fault Family: cam_position_sensor_circuit

Code P0340: Camshaft Position Sensor A Circuit Bank 1 or Single Sensor

Diagnostic & Technical Explanation

Code P0340 (Camshaft Position Sensor A Circuit Bank 1 or Single Sensor) sets when the ECM sees an open circuit, out-of-range voltage, or an erratic signal from the primary camshaft position sensor used for cylinder identification and cam-to-crank correlation — distinct from a VVT phaser's own actuator-position feedback sensor. Common causes are a corroded connector, a worn or contaminated reluctor/trigger wheel on the camshaft, an incorrect air gap, or chafed wiring between the sensor and the ECM.

Probability-Ranked Repair Procedures (4 Ranked Fixes)

Rank #1

Inspect and reseat the camshaft position sensor connector

Easy DIY

Parts Estimate: $5.0–$15.0 USD Labor Estimate: 0.4 Shop Hours

1. Locate the sensor at the valve cover, timing cover, or distributor housing per platform
2. Unplug and inspect for oil intrusion or corroded pins
3. Clean contacts and reseat fully
4. Clear the code and verify the engine restarts promptly

Required Replacement Parts: 🔧 Electrical contact cleaner

Rank #2

Replace the camshaft position sensor

Moderate DIY

Parts Estimate: $25.0–$130.0 USD Labor Estimate: 0.6 Shop Hours

1. Remove the sensor's retaining bolt and withdraw it from its bore
2. Inspect the O-ring and trigger wheel for wear or debris
3. Install the replacement sensor with a fresh O-ring
4. Clear codes and confirm cylinder identification on a scan tool

Required Replacement Parts: 🔧 Camshaft position sensor · 🔧 Sensor O-ring seal

Rank #3

Repair camshaft position sensor circuit wiring

Professional Required

Parts Estimate: $10.0–$60.0 USD Labor Estimate: 1.3 Shop Hours

1. Back-probe the signal, reference, and ground legs at the sensor connector
2. Voltage-drop test each leg back to the ECM
3. Repair chafed or corroded conductors with soldered, heat-shrunk splices
4. Confirm a clean signal waveform on a scope while cranking

Required Replacement Parts: 🔧 Automotive wiring repair kit (solder + heat-shrink)

Rank #4

Inspect the camshaft trigger wheel for timing-related damage