Technical Description of OBD-II Trouble Code
The circuit controlling the supply of reductant/regeneration 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 Mercedes Benz, BMW, Dodge, Volkswagen, Ram, Sprinter, Audi, etc. The specific repair steps may vary depending on the year, make, model, and powertrain configuration.
A stored code P2064 indicates that the powertrain control module (PCM) has detected excessive voltage in the control circuit for the reductant/regeneration supply pump.
Selective catalyst reduction (SCR) systems inject a reductant compound or diesel exhaust fluid (DEF) into the exhaust system to enhance filtration and reduce harmful emissions. The PCM or a stand-alone controller monitors and controls the SCR system, ensuring precise DEF injection to maintain optimal exhaust temperature and pollutant filtration.
The reductant/regeneration supply pump pressurizes the DEF in the liquid reductant system for use when required. The PCM monitors the supply pump voltage for consistent fluctuation and load percentage, as well as pressure sensors to detect system leaks.
If the PCM detects excessive voltage in the reductant/regeneration supply pump control circuit, it will store a code P2064 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 P2064 should be considered severe and addressed as quickly as possible, as it could disable the SCR system and potentially cause catalyst damage if not rectified promptly.
What are some of the symptoms of the code?
Symptoms of a P2064 trouble code may include:
What are some of the common causes of the code?
Possible causes for this code may include:
What are some P2064 troubleshooting steps?
To diagnose a code P2064, 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 your vehicle’s details, as it may provide helpful diagnostic information.
Use the scanner to retrieve all stored codes and freeze frame data. Write down this information before clearing the codes and 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 challenging to diagnose. In this case, the conditions contributing to the code being stored may need to worsen for an accurate diagnosis.
If the code is immediately reset, consult 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 tank supply pump according to the manufacturer’s specifications. Consider components that do not test within the maximum allowable parameters as defective.
Step 2
Use your vehicle diagnostic information source and the DVOM to test the reductant supply pump voltage (usually battery voltage) with the pump activated. If automatic activation is not possible under current conditions, use the scanner to manually activate the pump.
Step 3
If the reductant supply pump is functional, use the DVOM to test the input and output signal circuits from the fuse panel, PCM, and ignition switch. Disconnect all controllers before using the DVOM for testing.
