P2475 means the powertrain control module has detected an exhaust gas temperature (EGT) sensor signal on Bank 2, Sensor 4 that is below the expected voltage range. This usually indicates a low-voltage condition in the sensor circuit, such as an internal sensor fault, a short to ground in the wiring, or a connector problem. EGT sensors are used to monitor aftertreatment temperatures, so this code can affect diesel particulate filter regeneration strategies if left unresolved.
The temperature-sensing element can short internally or drift out of range, producing a lower-than-expected voltage signal. This is the most common cause of a circuit-low code.
The signal or reference circuit can chafe, melt, or contact metal components near the hot exhaust, causing voltage to be pulled low before reaching the control module.
Heat, moisture, and road contaminants can damage the sensor connector, leading to poor contact, shorting between pins, or abnormal resistance that mimics a low circuit condition.
An EGT sensor with the wrong resistance or voltage characteristics, or one installed in the wrong exhaust position, can report a signal outside the calibrated low threshold.
A rare control-module issue, such as a biased reference-voltage circuit or internal short, can set this code, but it should only be considered after the sensor and wiring are proven good.
Short trips are often possible, but continued driving can interfere with DPF regeneration and lead to soot buildup or a limp mode. Diagnosis should be performed as soon as practical.
No. Wiring shorts, connector corrosion, and harness damage are common causes, so the full circuit should be tested before replacing the sensor.
Usually not. PCM failure is uncommon for this code. The module should only be replaced after the sensor, wiring, and connectors have been thoroughly inspected and ruled out as the cause.
Location varies by engine and vehicle design. It is generally the EGT sensor on the bank containing cylinders 4–6 on a V-engine, with Sensor 4 often downstream of the DPF or SCR. Consult service information for the exact position.