P0340 Code Dodge Charger: Cam Sensor Circuit Diagnosis

What can set P0340—and how to separate it

The order below is evidence-driven, not a universal probability ranking. Vehicle year, repair history, companion codes and the operating condition in freeze frame change where diagnosis should begin.

Name the circuit before buying a sensor

Read every code and use the VIN-correct schematic to identify connector, bank and shared supplies. A generic parts listing cannot show whether the stored code concerns one cam sensor, a shared reference branch or plausibility against crank position.

Inspect harness bends near engine covers, brackets and hot components. Terminal spread or an internally broken wire may fail only when heat, vibration or engine movement recreates the original condition.

Loaded voltage tests expose false continuity

Verify reference voltage and ground with the circuit carrying an appropriate load. A digital meter can display full voltage through corrosion or a nearly open strand even though the signal collapses when the sensor operates.

Check terminal tension and contamination before piercing insulation. If multiple sensors share a supply and set codes together, disconnect branches methodically to find the short rather than replacing each sensor.

Use one capture to separate dropout from timing

Scope cam and crank simultaneously during crank, idle and the temperature where the fault occurs. Missing edges, noise or amplitude loss favor sensor, air-gap, connector or harness causes.

A repeatable phase displacement between otherwise clean signals points toward mechanical timing, a phaser or reluctor position. That evidence justifies deeper inspection; P0340 wording alone does not.

Save these scan-data clues

Freeze frame is a snapshot of conditions when the PCM matured the fault. It can distinguish an idle-only problem from a load, cold-start or monitor-completion problem. Clearing first throws that context away.

• Exact VIN, platform, model year and engine sales code
• All confirmed, pending and permanent companion codes
• RPM, load, coolant temperature and vehicle speed
• Relevant commanded and actual scan data
• Recent service, repairs and symptom conditions
• Manufacturer bulletin and current software/VIN status

A practical diagnostic workflow

1. 01
   Identify sensor and engine

   Cam layouts differ.

2. 02
   Read all codes

   Shared faults change priority.

3. 03
   Inspect harness routing

   Look for heat/chafe/contact.

4. 04
   Load-test circuits

   Continuity alone can mislead.

5. 05
   Scope cam and crank

   Separate dropout from phase shift.

6. 06
   Verify hot and cold

   Confirm sync and no pending code.

Why the model year changes the test

Modern Charger diagnostics span LX and LD rear-wheel-drive platforms, optional AWD and 2.7L, 3.5L, 3.6L Pentastar, 5.7L HEMI, 6.1L and 6.4L engines. Cylinder banks, oil-pressure control, cam sensing, EVAP plumbing and catalyst locations are not interchangeable. Confirm model year, VIN, engine sales code, build date and current PCM calibration before applying any test value, bulletin or diagram.

• 3.6L Pentastar uses multiple cam sensors; HEMI architecture differs.
• Older 2.7L and 3.5L engines require their own signal patterns.
• P0335 or several sensor codes may expose shared wiring or voltage.
• Stalling, no-start or timing noise makes diagnosis urgent.