Camshaft Position Sensor A Circuit Malfunction Bank 1
The camshaft position sensor (CMP) on Bank 1 has a circuit fault. This sensor is critical for engine timing.
SeverityCritical
CategoryIgnition
Est. Repair Cost$100–$400
Code TypePowertrain
DIY RepairYes
DifficultyIntermediate
⚡ Common Causes
›Faulty camshaft position sensor
›Damaged wiring or connector
›Reluctor wheel damage
›Timing chain jumped a tooth
⚠️ Symptoms
›Engine cranks but will not start
›Rough running
›Stalling
›Check engine light
›Hard start
✅ How to Fix — Step by Step
Step 1:Check sensor wiring and connector
Step 2:Test sensor with multimeter
Step 3:Replace camshaft position sensor
Step 4:Check reluctor wheel for damage
Step 5:Check timing chain
🔧 Diagnostic Tools Required
✔OBD-II Diagnostic Scanner
✔Digital Multimeter
✔Basic Hand Tools
✔Flashlight
✔Vehicle Service Manual
Using the correct diagnostic tools helps identify the root cause of P0340 before replacing parts unnecessarily. Always confirm the fault using live data and manufacturer-recommended diagnostic procedures.
🚗 Vehicles Commonly Reporting P0340
Chevrolet SilveradoFord ExplorerToyota CamryHonda OdysseyDodge ChargerJeep Grand Cherokee
❌ Common Mistakes to Avoid
✘Replacing the PCM before ruling out a much cheaper sensor or wiring fault
✘Not checking the wiring harness for chafing near the sensor for corrosion or a break
✘Overlooking a damaged reluctor wheel tooth as the actual cause
✘Skipping a sensor resistance test before buying a new part
📋 Technical Service Bulletins
Some manufacturers have TSBs for revised camshaft sensor part numbers with improved heat resistance, since sensor failure from underhood heat is a common documented pattern.
🏭 Manufacturer-Specific Notes
Chevrolet P0340
GM V8 trucks have a documented pattern of CMP sensor wiring harness chafing near the exhaust manifold — inspect the harness carefully, not just the sensor.
Dodge P0340
Chrysler/Dodge V6 and V8 engines can set this code from a failing sensor due to heat-cycling degradation — sensors in this position run hot and wear faster than average.
Honda P0340
On Honda V6 engines, this code combined with a no-start condition is most often a straightforward sensor failure rather than a wiring or PCM issue.
🎓 Expert Tip: A car that cranks normally but will not start, paired with this code, points strongly to the camshaft sensor itself — start there before spending time on wiring diagnostics.
💡 Pro Tip: P0340 can prevent the engine from starting entirely — check sensor connector first before expensive tests.
Repair Cost Estimate
Full Repair Estimate
$100–$400
DIY Possible?
YES
Severity
Critical
Diagnosis Time
25–45 minutes
Repair Time
30–90 minutes
Frequently Asked Questions
What does OBD2 code P0340 mean?+
P0340 stands for Camshaft Position Sensor A Circuit Malfunction Bank 1. The camshaft position sensor (CMP) on Bank 1 has a circuit fault. This sensor is critical for engine timing.
What causes code P0340?+
Faulty camshaft position sensor; Damaged wiring or connector; Reluctor wheel damage; Timing chain jumped a tooth
How do I fix code P0340?+
Check sensor wiring and connector; Test sensor with multimeter; Replace camshaft position sensor; Check reluctor wheel for damage; Check timing chain
How much does it cost to fix P0340?+
Estimated repair cost for P0340 is $100–$400.
Is P0340 DIY-friendly?+
Yes — P0340 is generally DIY-friendly with basic tools.
References
SAE J1979 — E/E Diagnostic Test Modes (OBD-II communication standard)
ISO 15031 — Road vehicles: communication between vehicle and external equipment for emissions-related diagnostics
Vehicle manufacturer service manual (consult your specific make and model)
