The code indicates that the powertrain control module (PCM) has detected a voltage higher than expected on the control circuit for the diesel exhaust fluid (DEF) injection valve located on Bank 2, Unit 2. This circuit-high condition typically signals a short-to-voltage in the wiring, an open ground return, or an internal fault within the dosing valve itself. The fault prevents the selective catalytic reduction (SCR) system from accurately metering reductant into the exhaust stream.
Internal short-to-power within the solenoid or valve electronics creates the high voltage reading detected by the PCM, or an open coil circuit causes a floating high signal.
The control wire has rubbed through its insulation and contacted a voltage source, or the low-side return is shorted to battery positive.
Moisture ingress at the valve or inline connector creates an unintended electrical path that biases the circuit voltage high or causes intermittent opens.
A break in the ground return wiring causes the PCM to see system voltage at its control pin when the driver is off, interpreting it as a continuous high signal.
Rare internal failure of the transistor driver within the control module causes incorrect voltage output or sensing, but this should only be considered after all external components are verified.
Short trips are possible, but the vehicle will likely enter a power-reduced mode to protect the exhaust aftertreatment system. Prolonged operation may result in hardened DEF deposits in the decomposition tube or SCR catalyst.
Almost never. The injection valve or wiring faults are far more common. PCM replacement should only be considered after the valve, connectors, and entire harness have been electrically verified as good.
Unit 2 refers to a secondary dosing valve, typically found on V-configuration engines with separate SCR bricks for each bank or on systems utilizing multiple injection points for enhanced reductant distribution.
No. This is strictly an electrical circuit fault. Contaminated or degraded fluid typically sets reductant quality, level, or concentration codes rather than circuit voltage codes.