Technical Description of OBD-II Trouble Code
The circuit controlling the reductant injection air pump is experiencing high voltage.
What does that mean?
This diagnostic trouble code (DTC) is a generic powertrain code that applies to many OBD-II vehicles (1996-newer), including vehicles from Dodge, Ram, Sprinter, Mercedes Benz, Ford, Audi, Volkswagen, etc. The repair steps may vary depending on the year, make, model, and powertrain configuration.
A stored code P2061 indicates that the powertrain control module (PCM) has detected excessive voltage in the circuit controlling the reductant injection air pump. The word “open” can be replaced with “disconnected.”
Modern diesel engines, which are larger and more powerful, cannot meet strict federal (U.S.) emission standards with just the EGR, diesel particulate filter/catalytic converter, and NOx trap. This is why selective catalytic reduction (SCR) systems were invented.
The SCR system injects a reductant compound or diesel exhaust fluid (DEF) into the exhaust, along with air, in front of the diesel particulate filter, NOx trap, and/or catalytic converter using the reductant injection valve (solenoid). The precise timing of DEF/air injection increases the temperature of the filtration element, allowing it to perform more efficiently. This improves the longevity of the filtration element and reduces harmful exhaust emissions released into the atmosphere. The PCM or a stand-alone controller monitors and controls the entire SCR system. The controller uses input from O2, NOx, and exhaust temperature sensors, among others, to determine the appropriate time for DEF and air injection. Precise DEF injection is necessary to maintain exhaust temperature within acceptable parameters and optimize pollutant filtration.
The reductant/regeneration supply pump pressurizes the DEF in the liquid reductant system when required. The PCM monitors the supply pump voltage for consistent fluctuation and load percentage. The PCM also monitors one or more pressure sensors in the reductant supply system to detect any leaks.
If the PCM detects excessive voltage in the circuit controlling the reductant injection air pump, it will store a code P2061 and may illuminate the malfunction indicator lamp (MIL). Multiple ignition cycles with a failure may be required for MIL illumination.
What is the severity of this DTC?
A stored code P2061 should be considered severe and addressed as quickly as possible. It could disable the SCR system and potentially cause catalyst damage if the underlying conditions are not rectified promptly.
What are some of the symptoms of the code?
Symptoms of a P2061 trouble code may include:
What are some of the common causes of the code?
Possible causes for this code may include:
What are some P2061 troubleshooting steps?
Ensure that the reductant/regeneration supply system is not losing pressure internally or externally. Activate the pump to create pressure and inspect the system for external leaks. Use a fuel pressure tester to manually monitor reductant system pressure. Check the supply pump and injector for leakage. If any leaks are found, they must be repaired before continuing with the diagnosis.
To diagnose a code P2061, you will need a diagnostic scanner, a digital volt/ohmmeter (DVOM), and vehicle-specific diagnostic information.
Refer to your vehicle information source to find a technical service bulletin (TSB) that matches the vehicle’s year, make, and model, as well as the engine size, stored codes, and exhibited symptoms. A TSB may provide helpful diagnostic information.
Use the scanner connected to the vehicle diagnostic connector to retrieve all stored codes and relevant freeze frame data. It is recommended to write down this information before clearing the codes and then test-drive the vehicle until the PCM enters readiness mode or the code is reset.
If the PCM enters readiness mode, the code is intermittent and may be more difficult to diagnose. In such cases, the conditions contributing to the stored code may need to worsen before an accurate diagnosis can be made.
If the code is immediately reset, the next step in the diagnosis will involve searching your vehicle information source for diagnostic flowcharts, connector pin-out charts, connector face views, and component testing procedures/specifications.
Step 1
Use the DVOM to test the reductant injection air pump control circuits, components, and sensors according to the manufacturer’s specifications. Faulty components or sensors can cause circuit failure codes. Sensors and components that do not test within the maximum allowable parameters should be considered defective.
Step 2
If the reductant air pressure is within specifications, the code P0259 persists, and all preliminary circuits, components, and sensors are functioning correctly, use the DVOM to test the input and output signal circuits between the sensors and the PCM/SCR controller. Disconnect all controllers before using the DVOM for testing.
