Technical Description of OBD-II Trouble Code
Performance Issue in Internal Control Module Engine RPM
What does that signify?
This generic powertrain diagnostic trouble code (DTC) is commonly found in many OBD-II vehicles, including but not limited to Dodge, Ram (Cummins), Ford, Chrysler, etc.
When code P061C is stored, it indicates that the powertrain control module (PCM) has detected an internal performance error in the engine RPM monitoring system. Other controllers may also detect an internal PCM performance error in the engine RPM monitoring system, contributing to the storage of code P061C.
Internal control module monitoring processors are responsible for various self-test duties and overall accountability of the controller. The PCM and other related controllers constantly monitor the input and output signals of the engine RPM calculation system. The engine RPM monitoring system also interacts with the transmission control module (TCM), traction control module (TCSM), and other controllers.
The PCM and other controllers monitor the engine RPM using input signals from the crankshaft position (CKP) sensor and the camshaft position (CMP) sensor/s. The desired engine RPM is programmed into the PCM and other controllers. The actual RPM is calculated using input data from the CKP and CMP sensors, as well as the throttle position sensor (TPS) and other engine and transmission sensors. The desired RPM is then compared with the actual RPM.
Whenever the ignition is on and the PCM is energized, internal engine RPM monitoring self-tests are initiated. In addition to running internal controller self-tests, the controller area network (CAN) also compares signals from each individual module to ensure that all controllers are functioning properly. These tests are performed simultaneously.
If the PCM detects an internal error in the desired engine RPM and actual RPM (which exceeds the maximum allowable threshold), code P061C will be stored and a malfunction indicator lamp (MIL) may illuminate. Multiple ignition cycles (with a failure) may be required for MIL illumination.
Photo of a PCM with the cover removed:
What is the severity of this DTC?
Codes related to internal control module processors should be considered severe. A stored code P061C could lead to serious drivability and fuel efficiency issues, occurring suddenly and without warning.
What are some of the symptoms of the code?
Symptoms of a P061C trouble code may include:
What are some of the common causes of the code?
Possible causes for this code may include:
What are some P061C troubleshooting steps?
Diagnosing a code P061C can be a challenging task, even for experienced and well-equipped professional technicians. Reprogramming may also be an issue, as it requires the necessary equipment to replace a defective controller and successfully complete the repair.
If there are ECM/PCM power supply codes present, they should be addressed before attempting to diagnose a P061C. Additionally, if there are CKP/CMP sensor or throttle position sensor (TPS) codes present, these should be diagnosed and repaired first.
Follow the manufacturer’s recommendations for testing CKP, CMP, and TPS sensors. The use of an oscilloscope can be particularly helpful when testing electromagnetic sensors. Replace any failed components as necessary.
Before declaring an individual controller defective, several preliminary tests can be performed. These tests require a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a reliable source of vehicle information. An oscilloscope may also prove to be useful.
Connect the scanner to the vehicle diagnostic port and retrieve all stored codes and freeze frame data. It is important to write down this information in case the code is intermittent. After recording all relevant information, clear the codes and test drive the vehicle until the code is reset or the PCM enters readiness mode. If the PCM enters readiness mode, the code is intermittent and will be more difficult to diagnose. In some cases, the condition that caused the P061C to be stored may need to worsen before a diagnosis can be made. If the code is reset, continue with the following preliminary tests.
When attempting to diagnose a P061C, information is crucial. Search your vehicle information source for technical service bulletins (TSB) that match the stored code, vehicle (year, make, model, and engine), and exhibited symptoms. If the right TSB is found, it may provide diagnostic information that will greatly assist in the diagnosis.
Use your source of vehicle information to obtain connector face views, connector pin-out charts, component locators, wiring diagrams, and diagnostic flow charts related to the code and vehicle in question.
Use the DVOM to test controller power supply fuses and relays. Test and replace any blown fuses as necessary. Fuses should be tested with the circuit loaded.
If all fuses and relays appear to be functioning properly, visually inspect the wiring and harnesses related to the controller. Also, check the chassis and engine ground junctions. Use your vehicle information source to obtain ground locations for the related circuits. Use the DVOM to test the integrity of the grounds.
Visually inspect the system controllers for signs of water, heat, or collision damage. Any controller that is damaged, especially by water, should be considered defective.
If the controller power and ground circuits are intact, suspect a defective controller or a controller programming error. Controller replacement will require reprogramming. In some cases, reprogrammed controllers may be available through aftermarket sources. Other vehicles/controllers will require on-board reprogramming that can only be done through a dealership or other qualified source.
