P0079 OBD Error Code: Problem & Solutions

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The P0079 fault code is defined as Exhaust Valve Control Solenoid Circuit Low Bank 1. It is a generic code indicates that the engine control module has tried to control the Bank 1 exhaust valve control solenoid and at the same time has found some issue. You can see this code in addition to P0078 and P0080 codes.

The P0079 fault code is defined as Exhaust Valve Control Solenoid Circuit Low (Bank1). This trouble code indicates an issue that is found when the Bank 1 exhaust valve solenoid is controlled by the engine control module and the system readings are found to be out of range. This code starts appearing when the engine control module detects low system voltage.

What causes this problem with the Exhaust Valve Control Solenoid Circuit Low B1?

• There can be some faults in the exhaust valve control solenoid, Bank 1
• Bad connection issues or failed corroded connector
• Wire harness and connection are the main reason behind the variable valve timing failure
• The engine oil level or pressure may be low
• The Service Engine Soon Lamp may start illuminating
• There can be some faults in the control solenoid
• Defects in the engine control module

1. Exhaust Valve Control Solenoid - If there is any fault detected in the Exhaust Valve Control Solenoid, it will flash OBD Code P0079. Replace faulty ECM components now!
2. Engine Control Module - Faulty ECM will affect the exhaust system and the engine performance and output. Replace faulty ECM components immediately.
3. Variable Valve Timing Solenoid - Faulty Variable Valve Timing Solenoid reduces the engine’s performance, fuel economy or emissions of the vehicle. Thus, replace it immediately.

We care for our customers and that’s why we can totally understand your problem. That’s the reason why we have listed out some major symptoms behind the flashing up of OBD Code P0079. They are mentioned here as follows:

Common Symptoms

• The check engine light may start illuminating on the dashboard
• Your vehicle may start suffering poor acceleration
• The overall fuel mileage or economy may start decreasing
• The car engine will lack performance
• There can be some defects in the engine control module and disabled variable valve timing

The car battery may be disconnected. If you want to access the module, then you must remove the trim panels

• Then you must disconnect the engine control module connections to remove the module
• Now the new module should be installed as well as secured. After that the electrical connections should be connected
• Reconnect the battery and then connect the charger to maintain the battery charge if needed. Reinstall the removed access or trim panels
• Program the engine control module to work with the vehicle for operation with an approved scan tool or methods
• Disconnect the charger and road test the vehicle for proper operation

The first thing which you have to do is to check for unplugged harness connections, look if there is any corrosion or some loose wires to connectors. The harness connectors from Solenoid and PCM should be unplugged, using a wiring diagram locate the + and - wires to the solenoid. The solenoid can be ground side or power side controlled; it all depends upon the application. If you want to determine the power flow in the circuit, then you can check with factory wiring diagrams. Using a digital volt ohm meter (DVOM) set to the ohms setting, check for resistance between each end of the wire. An over limit reading on the DVOM may be an open in the wiring, loose connection or terminal.

Make sure that the resistance should be around 1 ohm or less, if there is excessive resistance there may be corrosion or bad wiring between the solenoid and the power control module or the engine control module. Now with the electrical harness to the solenoid unplugged, using the DVOM set to ohms, you should check for resistance between each of the electrical terminals on the control solenoid itself. You can use the factory specifications or a known good control solenoid if available to determine if there is excessive resistance in the solenoid. If there is an over limit or excessive resistance reading on the DVOM, then it means that there are some faults in the solenoid

Inspect for a short to ground through the control solenoid by putting either DVOM lead to a known good ground and the other to each terminal on the control solenoid. If there is resistance present, the solenoid may be shorted internally. Intermittent conditions can prove to be quite a challenge to diagnose and in extreme cases may have to be allowed to worsen before a correct diagnosis can be made. Carefully inspect the electrical wiring and connectors for inconsistencies, including shorted or broken wiring and corroded connector faces All the timing components should be properly aligned and that engine oil level and engine oil pressure should be within acceptable specifications If all these checks are acceptable, then you must test the system components and voltage/resistance with the help of resistance figures and manufacturer’s reference voltage.

Common Mistakes When Diagnosing the P0079 Code

When you are diagnosing P0079 trouble code, then you must keep this thing in mind that you should not avoid following all the steps which are mentioned in proper order and be very careful that you do not miss any. You must test the control solenoid for proper operation before you start getting it replaced. Replacing the solenoid would only be beneficial if it has failed testing. This code can be seen intermittently.