P0340
High SeverityCamshaft Position Sensor A Circuit (Bank 1)
Engine System
What Does P0340 Mean?
No signal from the camshaft position sensor on bank 1. Needed for sequential fuel injection and ignition timing.
Common Fix
Replace camshaft position sensor
Estimated Cost (DIY)
$15 - $50
Symptoms
- ⚠️No start
- ⚠️Rough running
- ⚠️Loss of power
- ⚠️Check engine light
Related Symptoms
Common Causes
How to Diagnose P0340
- 1Check sensor connector
- 2Test sensor output
- 3Inspect wiring
- 4Replace sensor
OEM Diagnostic Flowchart
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Related Resources
Repair guides, symptom pages, and wiring diagrams related to P0340.
OEM Manual Evidence
Browse →A L L Diagnostic Trouble Codes ( DTC ) — 2013 GMC Truck Yukon XL Denali AWD V8-6.2L Service Manual | Operation CHARM Operation CHARM : Car...
A L L Diagnostic Trouble Codes ( DTC ) — 2013 GMC Truck Yukon XL Denali 2WD V8-6.2L Service Manual | Operation CHARM Operation CHARM : Car...
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A L L Diagnostic Trouble Codes ( DTC ) — 2013 GMC Truck Yukon XL 4WD V8-5.3L Service Manual | Operation CHARM Operation CHARM : Car repair...
Related Symptoms
Browse →No-crank and no-start complaints usually resolve into battery, starter, alternator, crank sensor, or fuel-delivery diagnosis.
A check-engine light is a graph entry point into code pages, symptom-specific diagnosis, and the exact repair categories most often associated with those failures.
Exact Vehicle Hubs
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Open the exact vehicle hub for a repair workflow commonly associated with P0340.
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Open the exact vehicle hub grounded by OEM manual evidence related to P0340.
Open the exact vehicle hub grounded by OEM manual evidence related to P0340.
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Exact Repair Workflows
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Open the exact repair flow most commonly associated with P0340 on this vehicle.
Open the exact repair flow most commonly associated with P0340 on this vehicle.
Open the exact repair flow most commonly associated with P0340 on this vehicle.
Open the exact repair flow most commonly associated with P0340 on this vehicle.
Open the exact repair flow most commonly associated with P0340 on this vehicle.
Related Codes
Cam sensor signal is irregular or does not correlate with crank sensor.
The ECM is not receiving a proper signal from the crankshaft position sensor. This sensor is critical for engine timing and fuel injection.
The crankshaft and intake camshaft positions are not synchronized on bank 1. This indicates a timing problem that can cause rough running or no-start conditions.
Frequently Asked Questions
- Can a bad cam sensor cause no-start?
- On some vehicles yes — the ECM needs both cam and crank signals to start.
- Is the cam sensor easy to replace?
- Usually yes — it bolts to the cylinder head or valve cover. 15-30 minute job.
Related Repair Guides
If your vehicle has triggered P0340, these DIY repair guides may help: