What does OBD2 code P0340 mean?
The engine control module (ECM) or powertrain control module (PCM) sets code P0340 when it registers that the Camshaft Position Sensor Circuit Malfunction performance has fallen below the manufacturer's required baseline. This triggers your vehicle's malfunction indicator lamp (MIL), commonly known as the Check Engine Light.
Is It Safe to Drive with Code P0340?
No, the vehicle may stall, fail to start, or enter limp-home mode because the engine computer cannot sync injector firing and spark timing with the pistons.
Symptoms of OBD2 Code P0340
Depending on your car model, symptoms for P0340 may vary. The most typical symptoms include:
- Check Engine Light on
- Engine cranks but will not start
- Intermittent stalling or engine stumbling
- Severe drop in engine power
What Causes Code P0340?
A variety of physical faults can trigger the P0340 code. Here are the most frequent culprits:
- Failed Camshaft Position (CMP) Sensor
- Damaged or corroded CMP sensor wiring connector
- Weak or discharged car battery
- Broken timing chain/belt teeth
Step-by-Step Diagnostic Routine
Before replacing any expensive components, run through these standardized troubleshooting steps:
- Scan codes with OBDAssistant. Check if crankshaft sensor codes (P0335) are also present.
- Check wiring connector on camshaft sensor for loose pins.
- Test CMP sensor resistance or output voltage signal.
Expected Repair Costs for P0340
$80 - $250. CMP sensors are typically inexpensive and mounted accessibly on the cylinder head.
Save on Diagnosis with OBDAssistant
OBDAssistant displays engine RPM and camshaft synchronization status, verifying if the sensor is sending pulses during engine cranking.
Frequently Asked Questions
Occasionally, the ECU can run on crankshaft backup maps, but it will have long starting cranks and very poor performance.