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
Honda Passport owners report the Idle Stop (automatic engine start-stop) feature causing dangerous stalling issues. When the engine auto-stops at red lights or in traffic, it fails to restart when the brake is released, leaving the vehicle stranded in traffic. The "Collision Mitigation System" warning light often appears during these incidents. The Idle Stop system is overly aggressive and doesn't account for battery health, A/C load, or hot weather conditions. Unlike some competitors, Honda doesn't have a shift interlock, so the vehicle can roll if stalled on a hill. Many owners permanently disable Idle Stop to avoid this issue.
Common Symptoms
- Engine fails to restart after auto-stop at red light
- Vehicle stalls in traffic when Idle Stop engages
- Collision Mitigation System warning light during stall
- Multiple restart attempts needed after auto-stop
- Engine cranks but won't start after Idle Stop
- Vehicle rolls backward when stalled on hill
- Battery warning light after failed restart
How to Fix
Temporary: Press Idle Stop button to disable every time you start the vehicle (annoyingly resets each ignition cycle). Permanent disable (DIY): Install Idle Stop Eliminator plug-in module ($40-80) that automatically disables the feature every startup - very popular on PassportForums. If stalling occurs: Shift to Park, turn off ignition, wait 10 seconds, restart engine. Battery related: If Idle Stop frequently won't engage or causes stalling, have battery tested (weak battery confuses system). Honda has released software updates but they don't fully address the issue.
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.
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.
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)
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 (1)
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: Passport, Accord, Del Sol.
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.
Looking for P0340 on a different make?
View P0340 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.