Technical Description of OBD-II Trouble Code
The exhaust valve control circuit for Cylinder 1 is experiencing low voltage.
What does that mean?
This is a generic powertrain diagnostic trouble code (DTC) that is applicable to many OBD-II vehicles manufactured from 1996 onwards. This includes vehicles from Dodge, Peugeot, Jeep, Chevrolet, Chrysler, and others. While the code is generic, the specific repair steps may vary depending on the year, make, model, and engine configuration of the vehicle.
OBD-II trouble code P3407, along with related codes P3405, P3406, and P3408, are associated with the exhaust valve control circuit for Cylinder 1.
The purpose of the exhaust valve control circuit for Cylinder 1 is to deactivate the exhaust valve in order to enable cylinder deactivation, such as the V4 mode in a V8 engine. This helps improve fuel economy during light load operation at idle or on the highway. The Engine Control Module (ECM) controls the activation and deactivation of four or eight cylinders in the engine. This is achieved through variable valve timing solenoids that turn the exhaust valves on and off as needed. This code specifically pertains to Cylinder 1, while the other three cylinders involved in this process are determined by the engine configuration and firing order. The variable valve timing solenoid for Cylinder 1 is typically located near the exhaust manifold in the vicinity of that cylinder, depending on the specific vehicle and configuration.
When the ECM detects low voltage or resistance in the exhaust valve control circuit for Cylinder 1, below the normal range threshold, it will set code P3407 and may illuminate the check engine light, service engine soon light, or both. In some cases, the ECM may disable the injector for Cylinder 1 until the issue is resolved and the code is cleared, resulting in a noticeable engine misfire.
Cylinder Deactivation Solenoids:
What is the severity of this DTC?
The severity of this code can vary greatly from moderate to severe, depending on the specific symptoms of the malfunction. A misfire should be addressed immediately, as it can cause permanent damage to internal engine components.
What are some of the symptoms of the code?
Symptoms of a P3407 trouble code may include:
What are some of the common causes of the code?
Causes for this P3407 code may include:
What are some P3407 troubleshooting steps?
The first step in troubleshooting any malfunction is to consult the Technical Service Bulletins (TSB’s) for the specific vehicle, based on its year, model, and engine. This can save time and money, as it provides a known fix for a known issue.
The second step is to check the engine oil level and ensure it is at the appropriate level. Then, inspect all components associated with the exhaust valve control circuit for Cylinder 1, looking for any visible physical damage. Depending on the specific vehicle, this circuit may include several components, such as the variable valve timing solenoid, switches, fault indicators, and the ECM. Conduct a thorough visual inspection of the associated wiring, checking for any obvious defects like scraping, rubbing, bare wires, or burn spots. Next, examine the connectors and connections for security, corrosion, and damaged pins. Refer to the specific technical data for the vehicle to confirm the configuration and identify every component involved in the exhaust valve control circuit for Cylinder 1.
Advanced Steps
The advanced steps are highly specific to the vehicle and require advanced equipment for accurate execution. These procedures typically involve using a digital multimeter and referencing the specific technical data for the vehicle. In this situation, an oil pressure gauge may also be useful in confirming any oil passage restrictions.
Voltage Checks
The reference voltage and acceptable ranges may vary depending on the specific vehicle and circuit configuration. The troubleshooting charts and appropriate sequence provided in the specific technical data will assist in achieving an accurate diagnosis.
If this process reveals the absence of a power source or ground, continuity testing may be necessary to check the integrity of the wiring, connectors, and other components. Continuity tests should always be performed with the power removed from the circuit, and normal readings for wiring and connections should show 0 ohms of resistance. Resistance or lack of continuity indicates faulty wiring that is open, shorted, or corroded, and it must be repaired or replaced.
What are some common repairs for this code?
Common Mistake
We recommend seeking professional mechanical assistance to resolve this issue. However, if that is not possible, we offer the option to permanently delete this specific DTC. All other codes will continue to be addressed. If you are interested in this option, please upload your ECU file to our portal.
