P2064 Reductant/Regeneration Supply Control Circuit High
OBD-II Trouble Code Technical Description
Reductant/Regeneration Supply Control Circuit High
What does that mean?
This diagnostic trouble code (DTC) is a generic powertrain code and applies to many OBD-II vehicles (1996-newer). That may include but is not limited to vehicles from Mercedes Benz, BMW, Dodge, Volkswagen, Ram, Sprinter, Audi, etc. Although generic, the exact repair steps may vary depending on year, make, model and powertrain configuration.
A stored code P2064 means that the powertrain control module (PCM) has detected an excessive degree of 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 in front of the diesel particulate filter, NOx trap, and/or the catalytic converter via the reductant injection valve (solenoid). The precisely timed DEF injection elevates the temperature of the filtration element and allows it to perform more efficiently. It enhances filtration element longevity and allows fewer harmful exhaust emissions to be released into the atmosphere. The entire SCR system is monitored and controlled by either the PCM or a stand-alone controller (which interacts with the PCM). Either way, the controller monitors the O2, NOx, and exhaust temperature sensors (as well as other inputs) to determine the appropriate time for DEF (reductant) injection. Precise DEF injection is necessary to maintain exhaust temperature within acceptable parameters and optimize pollutant filtration.
The reductant/regeneration supply pump is used to pressurize the DEF in the liquid reductant system for use, when required. Supply pump voltage is monitored by the PCM for consistent fluctuation and load percentage. The PCM also monitors one or more pressure sensors in the reductant supply system to determine if there is a leak in the system.
If the PCM detects a degree of voltage in the reductant/regeneration supply pump control circuit that exceeds allowable parameters, a code P2064 will be stored and a malfunction indicator lamp (MIL) may be illuminated. 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. The SCR system could be disabled because of it. Catalyst damage could result if the conditions which contributed to the code being stored are not rectified in a timely fashion.
What are some of the symptoms of the code?
Symptoms of a P2064 trouble code may include:
Reduction in fuel efficiency Excessive black smoke from vehicle exhaust Diminished engine performance Other SCR related codesWhat are some of the common causes of the code?
Causes for this code may include:
Defective reductant supply pump (overload) Open or shorted circuits in the reductant supply control Bad SCR controller/PCM or programming errorWhat are some P2064 troubleshooting steps?
A diagnostic scanner, a digital volt/ohmmeter (DVOM), and a source of vehicle specific diagnostic information will be required to diagnose a code P2064.
You may use your source of vehicle information to locate a technical service bulletin (TSB) that matches the vehicle year, make, and model; as well as the engine size, code/s stored, and symptoms exhibited. If you find one, it could yield helpful diagnostic information.
Use the scanner (connected to the vehicle diagnostic connector) to retrieve all stored codes and pertinent freeze frame data. It is a good idea to write this information down before clearing the codes then test-drive the vehicle until the PCM either enters readiness mode or the code is reset.
If the PCM enters readiness mode at this time, the code
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