P0340 on Honda: How to Diagnose & Fix
Camshaft Position Sensor Circuit Malfunction
3 Honda models · 3 documented issues · 3 critical · $40-$900 repair
P0340 on Honda by model: symptoms, diagnosis and fix
Every 1990s Accord four-cylinder (F22/F23) and the J30 V6 uses a rubber timing belt, and all are INTERFERENCE engines: if the belt snaps or jumps, pistons strike open valves and cause major internal damage (bent valves, often piston/head damage). The four-cylinders also drive a separate balance-shaft belt that must be replaced at the same time. Because these are now 25-35 year old cars, many are running on original or unknown-age belts — the single most consequential neglected-maintenance failure on the platform.
Common Symptoms
- Engine cranks but won't start (broken belt)
- Sudden loss of power while driving
- Rattling/slapping from timing cover (worn tensioner)
- Rough running after belt jumps a tooth
- No timing-belt service record
How to Fix
Replace the timing belt on schedule — roughly every 90,000 miles/72 months on 1990-96 cars and 105,000 miles/84 months on 1997+ cars, or immediately if age/history is unknown. Always do the water pump, tensioner, both cam/crank seals, and (on 4-cylinders) the balance-shaft belt in the same job. If a belt has already broken, repair means cylinder-head removal and valve replacement.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- AISIN TKH-007 timing-belt kit with water pumpOEMAISIN TKH-007
Confirm engine code before purchase; do not use on F22B1 VTEC, F23 or J30A1.
- AISIN TKH-006 timing-belt kit with water pump and balance beltOEMAISIN TKH-006
Complete scheduled timing service for the F22B1 VTEC and F23 four-cylinder branches Fitment/availability: 1994-1997 Accord 2.2L F22B1 VTEC and 1998-1999 Accord 2.3L F23 only after engine confirmation.
- AISIN TKH-011 timing-belt kit with water pumpOEMAISIN TKH-011
Do not substitute TKH-001 or any four-cylinder kit. Confirm VIN/engine and inspect separately required cam/crank seals.
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Sources for this issue (1)
The Del Sol uses a distributor-based ignition system with internal coil and ignition module. The distributor is prone to failure from moisture intrusion, internal coil cracking, and igniter module heat damage. Symptoms include intermittent no-start conditions, engine dying while driving, and misfires. The distributor is mounted at the rear of the cylinder head where it is exposed to engine heat and splash from the road. Remanufactured distributors are available but quality varies significantly between brands.
Common Symptoms
- Intermittent no-start condition
- Engine stalling while driving
- Random misfires across all cylinders
- Engine runs rough in humid conditions
- Check engine light for ignition-related codes
How to Fix
Confirm distributor failure by checking for loss of spark when the no-start or stall occurs, then test the internal coil and igniter/ICM against Honda service-manual resistance and output specs while inspecting the cap, rotor, housing seal, and connector for moisture or corrosion. On Del Sol models, the most reliable repair is usually replacing the complete distributor assembly with a quality OEM or premium new unit rather than a cheap remanufactured one, then installing a new cap/rotor if not included, verifying base ignition timing, and checking for oil leaks from the cam seal that can contaminate the distributor. Parts typically run about $180-$450 for a good distributor assembly, with total repair cost commonly $300-$700 depending on brand and labor; replacing only the igniter or coil is cheaper but often less durable if the housing or bearings are already heat-damaged.
Sources for this issue (2)
On some Honda Passports, the engine shuts off as designed when Auto Idle Stop engages at a light or in traffic, but then does not restart by itself when the driver lifts off the brake. The vehicle is left stopped in the lane, and some owners say it needed a jump start before they could drive on. Honda published service bulletins 23-008 and 23-009 in January 2023 for this no-restart condition. They cover the 2019-2022 Passport along with several Pilot, Ridgeline, Acura MDX and TLX model years. In March 2023 Honda sent owners of 2019-2022 Passports a warranty-extension letter. It extends coverage for the starter assembly, the starter relays and a related valve adjustment to 10 years from the original purchase date, with no mileage limit. NHTSA opened Engineering Analysis EA25-004 on March 26, 2025, which escalated an earlier preliminary evaluation (PE22-005). Its scope covers 2019-2025 Passports and about 2.2 million Honda and Acura vehicles in total. NHTSA counted 1,348 complaints, including 4 crashes and 2 injuries. It says it keeps receiving reports of failed restarts from owners who say the bulletin repair had already been done, and it is reviewing how well Honda's fix works. Many owners turn Idle Stop off each time they start the car, because the setting resets with every ignition cycle.
Common Symptoms
- Engine stays off when the brake is released after Auto Idle Stop shuts it down at a stop
- Vehicle is left stopped in traffic or at an intersection after an auto-stop
- Engine needs a manual restart or, in some reports, a jump start before the vehicle can be driven
How to Fix
First check: ask a Honda dealer whether your VIN is covered by service bulletins 23-008/23-009 and whether that work has already been done. The bulletin repair has two stages. Stage 1 is a PGM-FI (engine computer) software update. Stage 2 is used only if the software update does not fix the problem: the dealer replaces the starter assembly and the starter relays and, depending on model and year, adjusts the valves. On 2019-2022 Passports, Honda's warranty extension covers this stage 2 repair free for 10 years from the original purchase date, with no mileage limit, and the coverage carries over to later owners. Honda's letter says the repair takes about 3 hours. If you already paid for a starter and starter relays because of this problem, you may be able to get reimbursed through Honda, even if you no longer own the vehicle. Honda's customer support line for this is 1-888-234-2138. If the car still fails to restart after the bulletin work, report it to the dealer and to NHTSA. NHTSA's investigation EA25-004 is still open and is specifically looking into continued failures after the repair. The 2023 Passport is included in the NHTSA investigation but is not named in Honda's warranty-extension letter. Until the problem is fixed, press the Idle Stop OFF button each time you start the vehicle, because the setting resets with every ignition cycle.
Owner tips & cautions
- WarningCRITICAL: If Idle Stop fails on a hill, vehicle will roll backward (no shift interlock) - keep foot firmly on brake and shift to Park immediately.
- TipIf you prefer manual disable, lightly tap brake pedal when stopped - Idle Stop won't engage. Less annoying than pressing button every startup.
- TipWeak battery makes Idle Stop unreliable - if system is acting weird, get battery load tested before chasing gremlins.
Sources for this issue (2)
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 on a Honda?
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. On Honda it is documented across 3 models: Accord, Del Sol, Passport.
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 on a Honda?
Published repair estimates on Honda range from $40 to $900 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
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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.