P2046 indicates an intermittent fault in the reductant (DEF) temperature sensor circuit. This sensor monitors the temperature of the diesel exhaust fluid to ensure proper dosing for emissions control. An intermittent signal can cause the engine control module to log the code and may trigger warning lights or derate engine power.
The sensor itself is the most common failure point. Internal damage, corrosion, or age-related degradation can cause intermittent signal loss or erratic readings.
The sensor circuit includes wiring and connectors that can suffer from chafing, corrosion, or loose connections, especially in areas exposed to road salt, moisture, or heat.
An intermittent ground or power feed to the sensor can cause the circuit to drop out. Check for loose or corroded ground points and power supply connections.
In some systems, the temperature sensor shares a harness with the DEF heater or injector. A short or open in that harness can affect the sensor circuit intermittently.
A rare cause, but an internal fault in the PCM can produce intermittent sensor circuit codes. This should only be considered after thoroughly testing the sensor, wiring, and power/ground circuits.
You may be able to drive, but the vehicle may enter a reduced power mode to protect the emissions system. Continued driving could lead to further issues or failed emissions tests. It's best to diagnose and repair promptly.
No, that is almost never the correct fix. The PCM is rarely the cause of an intermittent sensor circuit code. Most cases are resolved by repairing the sensor, wiring, or connectors. Only consider PCM replacement after all other possibilities have been thoroughly eliminated.
Not directly. P2046 is an electrical circuit fault, not a fluid quality issue. However, contaminated or frozen DEF can sometimes damage the sensor or heater, leading to circuit problems. But the code itself indicates an electrical intermittent, not a fluid condition.
Intermittent faults are often caused by loose, corroded, or damaged connectors and wiring. Carefully inspect and clean all connections, repair any damaged wires, and ensure the sensor is securely mounted. Using a scan tool to monitor live data while wiggling the harness can help pinpoint the issue.