This code indicates that the Powertrain Control Module (PCM) has detected a lower than expected voltage in the electrical circuit for the exhaust gas temperature sensor located at Bank 1 Sensor 5. This typically points to a wiring issue or a short to ground in the sensor circuit, causing the PCM to receive inaccurate temperature readings from the exhaust system.
Chafed, melted, or damaged wiring harnesses can cause the sensor signal wire to short to ground, resulting in a low voltage reading.
The sensor itself may have internally shorted, causing it to output a consistently low or zero voltage signal to the PCM.
Corrosion, spread pins, or loose connections at the sensor or PCM connector can increase resistance or ground the signal circuit.
Diesel exhaust fluid or moisture intrusion into the sensor connector can create a conductive path that pulls the signal voltage low.
A rare internal failure within the PCM could incorrectly interpret the sensor voltage as low, though this is highly uncommon.
No, it almost never does. Mechanics are frequently told to replace the PCM for this code, but that is usually incorrect. The cause is almost always a wiring short, a bad connection, or a failed exhaust gas temperature sensor itself.
It depends on the vehicle, but you should exercise caution. In diesel vehicles, a faulty exhaust temperature reading can prevent the diesel particulate filter from regenerating, which can eventually lead to a clogged exhaust and severe performance issues.
Bank 1 refers to the side of the engine containing cylinder number one. Sensor 5 is the fifth exhaust gas temperature sensor in the exhaust stream for that bank, typically located far downstream near or after the diesel particulate filter. Consult a model-specific service manual for the exact location.
It should be diagnosed and repaired relatively soon. While the vehicle may still drive, ignoring the issue can lead to a clogged DPF, reduced fuel efficiency, and potentially costly damage to other emissions components.