Mitsubishi Lancer Evo 9 C3378 Engine Trouble Code
What is Mitsubishi Lancer Evo 9 C3378?
With Mitsubishi Lancer Evo 9 C3378, you may drive for several weeks with a malfunctioning MAF sensor, but expect decreased fuel economy and eventual stalling. Shop replacement costs $240–$400 depending on vehicle. The labour is straightforward, with most cost from the part itself.
C3378 on the Mitsubishi Lancer Evo 9
The Mitsubishi Lancer Evo 9 is particularly susceptible to C3378 faults when the engine management unit receives conflicting sensor data. Owners report that C3378 on Mitsubishi Lancer Evo 9 most commonly surfaces after 60,000 miles, especially when routine service intervals have been missed.
Code Information
| Code Type: | OBD-II Chassis (C) Trouble Code |
| System: | Chassis |
| Vehicle: | Mitsubishi Lancer Evo 9 |
| Brand: | Mitsubishi |
| Model: | Lancer Evo 9 |
| Code: | C3378 |
C3378 Mitsubishi Lancer Evo 9 Symptoms
Check Engine Light
Illuminated Mitsubishi Lancer Evo 9 dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration on the Mitsubishi Lancer Evo 9
Starting Problems
Difficulty starting the engine
Poor Fuel Economy
Increased fuel consumption on the Mitsubishi Lancer Evo 9
Increased Emissions
Failed emissions test due to C3378
C3378 Code Structure
Understanding what each digit means in the C3378 chassis trouble code:
| C | 3 | 3 | 7 | 8 |
|---|---|---|---|---|
| Chassis Code | Ignition System Or Misfire | Throttle/Pedal Position Sensor/Switch A Circuit Intermittent | Cylinder 10 Contribution/Balance Fault | Clutch Position Sensor Circuit Malfunction |
How to Fix Mitsubishi Lancer Evo 9 C3378
Diagnostic Steps:
Poor running symptoms align with MAP sensor malfunction. In some cases, a faulty MAP sensor will not trigger a code. The issue may represent separate wiring concerns requiring individual diagnosis.
Repair Solution:
Most manufacturers number cylinders sequentially from front to back. Ford V-engines start with cylinder 1 at front left. In V-6 engines, cylinder 4 is front right; in V-8 engines, cylinder 5 occupies that position.
Technical Notes:
For C3378, verify VCT solenoid operation. Look for stuck or sticking valves caused by contamination. Consult vehicle-specific repair manual for proper component testing procedures.
Mitsubishi Lancer Evo 9 C3378 Repair Cost
Addressing C3378 on your Mitsubishi Lancer Evo 9 typically involves: dealer diagnostic fee $95–$150, oxygen sensor replacement $180–$320 (parts + labour), or catalytic converter replacement $1,800–$2,400 if damage has progressed. Independent specialist garages often charge 20–30% less than franchised dealers for identical work.
C3378 Description
C3378 engine trouble code is related to Clutch Position Sensor Circuit Malfunction.
Main Cause
The primary reason for C3378 OBD-II Engine Trouble Code is: Throttle/Pedal Position Sensor/Switch A Circuit Intermittent.
Common C3378 Misdiagnosis on the Mitsubishi Lancer Evo 9
Workshop technicians sometimes replace the entire ignition coil assembly on the Mitsubishi Lancer Evo 9 when C3378 accompanies a cylinder-specific misfire. In many cases, only the spark plug in the misfiring cylinder has fouled; a $8 plug replaces a $140 coil pack.
DIY Repair Guide: C3378 on Mitsubishi Lancer Evo 9
When replacing sensors on the Mitsubishi Lancer Evo 9, always use anti-seize compound on the thread and dielectric grease on the electrical connector. This simple habit prevents the most common causes of sensor-related callbacks after repair.
Preventing C3378 on the Mitsubishi Lancer Evo 9
After any fuel system repair on the Mitsubishi Lancer Evo 9, always perform a fuel-trim reset and adaptation drive. Skipping this step leaves the ECU operating on pre-repair learned values, which can generate false C3378 alerts for weeks after the fix.
Frequently Asked Questions — Mitsubishi Lancer Evo 9 C3378
A: Contaminated or low-octane fuel can temporarily trigger C3378 through knock retard and lean/rich excursion events. If the code appeared shortly after a fill-up at an unfamiliar station, running the tank close to empty and refuelling with premium is a sensible first step.