P0340 on Mitsubishi: How to Diagnose & Fix
Camshaft Position Sensor Circuit Malfunction
2 Mitsubishi models · 2 documented issues · $150-$550 repair
P0340 on Mitsubishi by model: symptoms, diagnosis and fix
The 4G63 uses a cam angle sensor (an optical sensor mounted in the distributor housing on the exhaust cam) to provide the crank/cam timing signal to the ECU. With age the CAS optical disc, LEDs/phototransistors, and internal bearing wear out and produce erratic or lost signals. On 1G cars the CAS is base-timing adjustable; on 2G it is fixed. Failure is a classic cause of intermittent no-start, hot-soak no-start, and random stalling on these cars, and it can be intermittent enough that tapping the sensor temporarily restores it. It is frequently misdiagnosed. (Note: crankwalk can mimic these symptoms by physically disturbing the CAS drive.)
Common Symptoms
- Intermittent no-start / crank but no spark
- Hot-start failure (won't restart until it cools)
- Random stalling while driving
- Rough running that comes and goes
- Symptoms temporarily clear when the sensor is tapped
How to Fix
Diagnose by checking for spark and injector pulse and verifying the CAS output signal on a scope/meter; a bearing that has play or a signal that cuts out when hot confirms it. Replace the cam angle sensor (or the complete optical distributor assembly). On 1G cars, re-set base ignition timing after replacement. Ensure grounds and the connector are clean, as poor grounds mimic CAS faults.
Sources for this issue (2)
The crankshaft position sensor on the 2.4L (4G64) Galant fails with age and heat, sometimes intermittently. Because the ECU uses this signal to fire spark and injection, a failing sensor typically produces a hard-start, an engine that cranks but will not start (often after the engine warms up), or sudden stalling while driving, frequently with the check-engine light on. The sensor is a three-pin Hall-effect unit mounted to the front of the engine reading a trigger plate.
Common Symptoms
- Engine cranks but will not start (often when warm)
- Intermittent stalling while driving
- Hard starting
- Check-engine light illuminated
How to Fix
Test the sensor per the diagnostic procedure (resistance/signal check) and replace if out of spec. It is an inexpensive part with about an hour of labor. A no-start with codes P0335/P0340 should prompt inspection of both the crank and cam sensors and confirmation that the timing belt has not jumped a tooth.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- API crankshaft position/reference sensor 7122-07811514OEMAPI 7122-07811514
Diagnosed 1994-1998 Galant CKP branch after 4G64/VIN and connector confirmation Fitment/availability: The inspected direct page lists 1994-1998 Galant, explicitly identifies 1994 4G64 VIN G fitment and shows the harness/connector specifi…
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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 Mitsubishi?
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 Mitsubishi it is documented across 2 models: Eclipse, Galant.
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 Mitsubishi?
Published repair estimates on Mitsubishi range from $150 to $550 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.