P0340 (generic)
Camshaft Position Sensor Circuit
System: Powertrain · Ignition / Misfire
Severity: moderate · Inspection: often fails
Description
CMP sensor circuit issue. Can cause hard start, stall. Replace sensor; check wiring.
Diagnostic snapshot P0340
- Difficulty
- 6/10 — Intermediate diagnostics
- Est. repair cost
- $120 – $450 (parts + typical shop labor)
- Common symptoms
- Check engine light (MIL)
- Hard starting / long crank before start
- Stall at idle or right after start
Diagnostic workflow
- Confirm P0340 with a live scan — note pending vs stored and freeze frame data.
- Verify reported symptoms: Check engine light (MIL), Hard starting / long crank before start, Stall at idle or right after start.
- Inspect wiring/connectors and related sensors before replacing modules.
- Most likely fixes: Replace camshaft position sensor / inspect timing chain stretch; Spark plug / coil / ignition diagnosis.
- Clear codes and road-test; re-scan after two drive cycles if the monitor must set.
Topics
- OBD-II and scan tools (guide)
- Powertrain DTCs (P-prefix) (system)
Related symptoms
- Check engine light (MIL) (weight 0.800)
- Hard starting / long crank before start (weight 0.650)
- Stall at idle or right after start (weight 0.550)
Common fixes (curated)
- Replace camshaft position sensor / inspect timing chain stretch (rank 1)
- Spark plug / coil / ignition diagnosis (rank 2)
Related articles
Diagnostic bundle (JSON)
Machine-readable graph: related codes, symptoms, fixes, topics, articles, and curated sources rows. Append &external=1 for optional YouTube / Google CSE hits when API keys are configured (see web/.env.example).