What Does It Mean?
This is a generic powertrain diagnostic trouble code (DTC) and generally applies to OBD-II vehicles. Vehicle makes may include, but are not limited to, Dodge, Chrysler, Ford, Chevrolet, Toyota, Honda, Nissan, etc.
The ECM (Engine Control Module) is not only responsible for monitoring and adjusting many sensors, solenoids, actuators, valves, etc., but also for ensuring all these components work seamlessly and together to meet desired values. All this to ensure you get the most out of your vehicle’s fuel economy and performance. In this case, if you get a P0659 or a related code, depending on your make and model, you may experience transmission handling issues.
It’s important to note that, in my experience with European models, I have also seen this code as an EVAP diagnostic code. After highlighting the potential differences, it goes without saying that you should refer to your service manual to ensure proper diagnostic direction. Most of the time, your symptoms will be a strong indicator of the systems/components you’ll be working with to correct the fault.
Regarding P0659 and related codes, the ECM has detected an abnormal value in the actuator supply voltage circuit. It recognizes the anomaly by comparing actual values to desired ones. If they fall outside the desired range, it illuminates the MIL (Malfunction Indicator Lamp) on your dashboard. It must monitor this fault for several drive cycles before turning on the MIL. Be sure to look for the “A” designation in the circuit. Depending on your make and model, this could designate a specific wire, harness, location, etc. That said, always use OEM (Original Equipment Manufacturer) service information for this.
This could also be detected by the TCM (Transmission Control Module) depending on the description your particular make and model has for this code.
P0659 (Actuator Supply Voltage Circuit A, High Circuit) is active when the ECM or TCM has detected a high voltage condition in the actuator “A” supply voltage circuit.
P0659
How Severe Is This DTC?
The severity here is moderate, generally speaking. Since there are multiple code descriptions, you must exercise caution during diagnosis. Proper service data will be necessary. If this happens to be a transmission code in your case, you certainly want to repair it as soon as possible. Daily use of a vehicle with an active transmission code is a risk we do not want to take.
What Are Some of the Symptoms of the Code?
Symptoms of a P0659 diagnostic trouble code may include:
Poor shifting
Lack of torque
Stuck in gear
CEL (Check Engine Light) illuminated
Overall poor driveability
Limited power output
Poor fuel consumption
Abnormal engine RPM/speed
What Are Some of the Common Causes of the Code?
Causes
of this P0659 fault code may include:
Water intrusion
Melted/broken connector(s)
General electrical issue (e.g., charging system problem, bad battery, etc.)
What Are the Diagnostic and Troubleshooting Steps for P0659?
The first step in the troubleshooting process for any malfunction is to check the Technical Service Bulletins (TSBs) for known issues with the specific vehicle.
Advanced diagnostic steps become very vehicle-specific and may require the proper equipment and advanced knowledge to perform accurately. We include the basic steps below but refer to a year/make/model/powertrain-specific repair guide for steps specific to your vehicle.
Basic Step #1
How you approach your diagnosis will depend on your make and model and the symptoms you are experiencing. But generally speaking, the first thing to do is clear the codes with your scanner and drive the vehicle until it becomes active again. If it does, after locating the correct circuit/harness we are working with, inspect it for any damage. It might be routed under the vehicle where road debris, dirt, ice, etc., can damage the underlying circuits. Repair any open and/or chafed wires if found. Additionally, it would be a good idea to inspect the involved connectors. You can disconnect them to inspect the pins for any that are bent or damaged, which could cause electrical issues. Sometimes, high resistance in a circuit can cause excessive heat. To the point that it can burn through the insulation! This would be a good sign that you have found your problem.
NOTE: Always solder and heat-shrink damaged wires. Especially when they are exposed to the elements. Replace connectors with OEM ones to ensure proper electrical connections.
Basic Step #2
Locate your actuator using your service information. Sometimes these can be accessed from the outside. If that’s the case for you, you can check the integrity of the actuator itself. The desired values involved in this test vary widely, but be sure to have your multimeter and service manual on hand. Always use proper test pin connectors to avoid unnecessary damage to the connections. If the recorded values are outside the desired ones, the sensor may be considered faulty and should be replaced with a new one.
Basic Step #3
Take a look at your ECM (Engine Control Module) and TCM (Transmission Control Module) for any obvious damage. Sometimes they are located in a spot prone to trapping water and causing corrosion. Any green powder present should be considered a red flag. A licensed technician should take it from here given the complexity of ECM diagnosis.
This article is strictly for informational purposes only, and the technical data and service bulletins for your specific vehicle should always take precedence.