P0340: How to Diagnose & Fix — Camshaft Position Sensor Circuit Malfunction
56 vehicles · 20 makes · $30-$8,000 repair
How to diagnose and fix P0340: most-reported vehicles
Ranked by owner reports. Each card gives the symptoms, how to confirm the cause, the fix, parts and sources for that vehicle.
Ford Expedition · 2005–2014
The 5.4L 3-valve (3V) Triton V8 in 2005-2014 Ford Expedition is notorious for cam phaser failures and timing chain stretch, representing one of the most common and expensive repairs on these trucks. The VCT (Variable Camshaft Timing) system uses oil pressure to actuate the cam phasers - when phasers wear out or chains stretch, the engine sets multiple camshaft correlation codes and rattles on startup. The factory oil pump also wears out at similar intervals, compounding the problem. Running low on oil or using the wrong viscosity dramatically accelerates failure. Left unrepaired, a failed phaser can cause a chain to jump timing, resulting in bent valves and catastrophic engine damage. Repair typically requires complete timing system replacement including both cam phasers, both timing chains, guides, and tensioners - a 12-16 hour job.
Common Symptoms
- Loud rattling/knocking from engine on cold start (top-end rattle)
- Check engine light with codes P0340, P0341, P0344, P0345, P0346, P0349 (cam sensor/phaser codes)
- Codes P0016, P0017, P0018, P0019 (camshaft-crankshaft timing correlation)
- Rough idle, especially when cold
- Engine surging at idle
- Loss of power and poor fuel economy
- Rattle that worsens on acceleration at low RPM
- Multiple misfire codes accompanying timing codes
How to Fix
Complete timing system overhaul: replace both VCT cam phasers, both timing chains, all chain guides, and tensioners as a complete kit. A Ford/Motorcraft 3V cam phaser repair kit (phaser sprockets, timing chains, tensioners and guides) or equivalent is recommended. Also replace the oil pump if over 80,000 miles - worn pump cannot supply adequate oil pressure for VCT system. Use 5W-20 full synthetic oil only. Change oil every 5,000 miles maximum. Labor: 12-16 hours on Expedition due to 4WD and engine mounts.
Sources for this issue (2)
Acura MDX · 2001–2006
First-generation MDX models with the J35 V6 are prone to timing belt tensioner bearing failure and simultaneous water pump leaks when the timing belt service is neglected past 105,000 miles. The hydraulic tensioner loses pressure, allowing the belt to skip teeth and potentially bend valves on this interference engine.
Common Symptoms
- Ticking or rattling noise from front of engine on startup
- Coolant leak from water pump weep hole
- Engine runs rough after high-mileage
- Squealing noise from belt area
- Engine misfires at high RPM
How to Fix
Replace the timing belt, tensioner, water pump, and all idler pulleys as a complete kit at 105,000 miles or 7 years, whichever comes first. Use genuine Honda/Acura components or the verified AISIN kit matched to the year split: TKH-001 for 2001–2002 and TKH-002 for 2003–2006. Never reuse the old tensioner even if it appears functional. This is a critical interference engine — a broken belt destroys the valves.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- 2001–2002 AISIN TKH-001Fits 2001-2002
Verified repair component. Approved replacement: 2001–2002 AISIN TKH-001.
- 2003–2006 AISIN TKH-002Fits 2003-2006
Verified repair component. Approved replacement: 2003–2006 AISIN TKH-002.
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
Owner tips & cautions
- WarningThis is an INTERFERENCE engine. If the timing belt breaks, the pistons hit the valves and you are looking at a $3,000-5,000 head repair. Do the belt, tensioner, and water pump together at 100k miles — it is the single most important maintenance item on these engines.
Sources for this issue (2)
GMC Envoy · 2002–2009
The 4.2L LL8 inline-6 engine in the 2002-2009 GMC Envoy is notorious for crankshaft position sensor failures that cause intermittent stalling and no-start conditions. The sensor is located on the side of the engine block and is exposed to heat soak from the exhaust manifold, accelerating its failure. A failing sensor causes the PCM to lose track of crank position, resulting in the engine cutting out without warning — often at highway speed. The issue tends to be intermittent at first, making diagnosis challenging. Replacement is straightforward and the part is inexpensive.
Common Symptoms
- Engine stalls without warning at any speed
- Hard start or no-start after hot soak
- Check engine light with code P0335 or P0336
- Engine cranks but won't fire when hot
- Intermittent stall that restarts after cooling down
- Rough idle followed by stall
How to Fix
Replace crankshaft position sensor (ACDelco 213-3521 or Delphi SS11378). Clear codes and test. If stalling continues, inspect camshaft position sensor (ACDelco 213-3522) as secondary cause. Verify PCM software is current — older PCM calibrations make the engine overly sensitive to sensor signal dropout.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Engine Crankshaft Position SensorCross-ref235-1078
Fitment confirmed against the ShowMeTheParts catalog for this vehicle's year and engine.
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
Sources for this issue (1)
Hyundai Elantra · 2011–2013
Jeep Commander · 2006–2010
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P0340 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0340 mean?
P0340 stands for "Camshaft Position Sensor Circuit Malfunction." This code means the engine computer lost or received an erratic signal from the camshaft position sensor. That sensor tells the computer the exact position and speed of the camshaft, which it uses together with the crankshaft sensor to time fuel injection and spark precisely. When the camshaft signal is missing, intermittent, or out of range, the computer sets P0340. Symptoms often include hard starting, stalling, rough running, or a no-start because the engine can't time itself correctly.
What are the most common causes of P0340?
The most common causes of P0340 are: Failed camshaft position sensor, Corroded or loose sensor connector, Damaged or shorted sensor wiring, Bad reluctor/tone ring on the camshaft, Loose timing chain/belt or jumped timing, Metal debris or oil contamination on the sensor tip, Poor sensor power or ground supply, Faulty PCM/ECM (rare). The specific cause varies by vehicle.
How much does it cost to fix P0340?
Repair costs for P0340 range from $30 to $8,000, depending on the vehicle and root cause.
Which vehicles are affected by P0340?
Au7o has documented P0340 across 56 vehicle models from 20 manufacturers: Acura, Cadillac, Chevrolet, Chrysler, Dodge, Ford, GMC, Honda, Hyundai, Infiniti, Jeep, Kia, Mazda, Mitsubishi, Nissan, RAM, Renault, Saturn, Toyota, Volvo.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.