P205B - REDUCTANT TANK TEMPERATURE SENSOR CIRCUIT RANGE / PERFORMANCE

EGR Systems (Exhaust Gas Recirculation) significantly reduce the pollutants produced by the engine. However, since diesel engines produce a higher amount of emissions, the SCR System (Selective Catalytic Reduction) was also implemented in these engines. The latter injects Diesel Exhaust Fluid through a solenoid valve, a process that increases the temperature of the Diesel Particulate Filter to achieve better performance and a reduction in the release of emissions.

A booster supply pump is located in this system, which allows the Diesel Exhaust Fluid to be pressurized when necessary. The PCM monitors the voltage supply to this pump to check that there is consistency in voltage delivery, as well as an adequate charge level. The PCM also monitors one or more pressure sensors to determine if there are any leaks in the system.

If the Powertrain Control Module finds a voltage level in the Reducer Tank Temperature Sensor circuit that shows performance problems in the circuit, it will set the P205B OBDII fault code.

• Check Engine light comes on.
• Fuel consumption increases.
• Excessive amounts of smoke are expelled from the exhaust.
• The engine significantly loses power.
• Other SCR systems related to DTCs are set.

The reasons for setting the P205B OBD2 diagnostic code are:

• There may be bad wiring in the circuit causing a short or open circuit.
• The Reducer Tank Temperature Sensor could be faulty.
• Possibly the SCR System controller has been damaged.

To resolve the P205B OBDII error code you must do the following:

• As a first step, you need to consult the TSB (Technical Service Bulletins).
• Inspect all the components of the electrical circuit to check for obvious damage. If you find burnt wires or corroded connectors, proceed to make any necessary repairs or replacements.
• Use a DVOM to perform voltage checks on the temperature sensor of the reduction tank. If you determine that it is not functioning properly, you should replace it.
• With the DVOM, test the input and output signal circuits between the sensor and the PCM or SCR System Any out-of-range results will require repairs.