2012 Mitsubishi Eclipse Spyder OBD2 Code P0078 Exhaust Valve Control Solenoid Circuit (Bank 1)

P0078 code definition

Exhaust Valve Control Solenoid Circuit (Bank 1)

What the P0078 code means

P0078 is a generic OBD2 code indicating that the Engine Control Module (ECM) has tried to control the Bank 1 exhaust valve control solenoid, and found an issue present. This code may be seen in addition to P0079 and P0080.

What causes the P0078 code?

• An open or short in wiring
• Poor or faulty electrical connections
• Failed control valve solenoid
• Faulty ECM

What are the symptoms of the P0078 code?

• Check Engine Light is on
• Poor acceleration
• Poor fuel economy

How does a mechanic diagnose the P0078 code?

• Hooks up a professional grade scan tool to your 2012 Mitsubishi Eclipse spyder's OBD2 port to detect any codes present

• Observes the freeze frame data to note the conditions of your 2012 Mitsubishi Eclipse spyder when the Check Engine Light was first illuminated

• Clears the codes and performs a road test under the circumstances seen in the freeze frame data

If the code reappears during the test drive:

• Performs a visual inspection for all wiring and connectors associated with the valve control circuit

• Uses a scan tool to observe the data from the exhaust valve control solenoid and its changes over time

If the sensor is operating properly, then the manufacturer's test of the ECM should be performed.

Common mistakes when diagnosing the P0078 code

Any Check Engine Light can be easy to diagnose, or difficult due to intermittent issues and other factors. Following all steps in the proper order and not condemning any part until it is inspected and tested is the route to success. The most common mistake is replacing the solenoid before proper diagnosis is performed.

How serious is the P0078 code?

The P0078 code typically just elicits the Check Engine Light without any other adverse engine issues noticed. In the circumstances where your 2012 Mitsubishi Eclipse spyder accelerates poorly or the fuel mileage suffers, this code should be diagnosed by a qualified technician as soon as possible to ensure safe driving and normal operation.

What repairs can fix the P0078 code?

• Repairing or replacing an open or short in wiring
• Replacing faulty exhaust valve control solenoid
• Replacing the ECM
• Correcting any connection issues

Additional comments for consideration regarding the P0078 code

The exhaust valve control solenoid plays an important factor in modern engines that have variable valve timing and is needed for proper operation of this system. Variable valve timing adds better fuel economy and aides in acceleration in 2012 Mitsubishi Eclipse spyders equipped with it. Most modern engines use variable valve timing of some type.

A professional level scan tool that allows you to see the advanced sensor data such as live readings, sensor voltage, and sensor resistance is required to accurately diagnose this code.

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P0078

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