Technical Description of OBD-II Trouble Code
The circuit controlling the supply of reductant/regeneration is experiencing low 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, and others. The specific repair steps may vary depending on the year, make, model, and powertrain configuration of the vehicle.
A stored code P2063 indicates that the powertrain control module (PCM) has detected insufficient 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 before the diesel particulate filter, NOx trap, and/or catalytic converter. This injection raises the temperature of the filtration element, improving its efficiency and reducing harmful exhaust emissions. The PCM or a stand-alone controller monitors and controls the entire SCR system, using input from sensors to determine the optimal time for DEF injection. Precise injection is necessary to maintain acceptable exhaust temperature and optimize pollutant filtration.
The reductant/regeneration supply pump pressurizes the DEF in the liquid reductant system when needed. The PCM monitors the voltage of the supply pump for consistent fluctuation and load percentage. It also monitors pressure sensors in the reductant supply system to detect any leaks.
If the PCM detects voltage in the reductant/regeneration supply pump control circuit that is below the allowable parameters, it will store a code P2063 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 P2063 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 resolved promptly.
What are some of the symptoms of the code?
Symptoms of a P2063 trouble code may include:
What are some of the common causes of the code?
Possible causes for this code include:
What are some P2063 troubleshooting steps?
To diagnose a code P2063, you will need a diagnostic scanner, a digital volt/ohmmeter (DVOM), and vehicle-specific diagnostic information.
Consult your vehicle information source to find a technical service bulletin (TSB) that matches your vehicle’s year, make, model, engine size, stored codes, and symptoms. A TSB 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, 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 this case, the underlying conditions may need to worsen before an accurate diagnosis can be made.
If the code is immediately reset, you will need to refer to 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 manufacturer specifications. Any components that do not test within the maximum allowable parameters should be considered defective.
Step 2
Use your vehicle diagnostic information source and the DVOM to test the voltage of the reductant supply pump (usually battery voltage) when the pump is activated. If current conditions do not allow for automatic activation, use the scanner to manually activate the pump.
Step 3
If the reductant supply pump is functioning properly, 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.
