P2046 Reductant Temperature Sensor A Circuit Intermittent

P2046 records short dropouts or jumps in the signal of reductant temperature sensor A. No manufacturer documents this code publicly. Deutz, the clearest user of the P2042 group, lists only an open line, a ground fault, both shorts and a plausibility error for this sensor, but no intermittent entry. How such a check can work is shown by GM's tank sensor test P205E in the 2025 DEF controller: it fails when the reading moves by more than 4 °C inside a ten-sample window, three times out of nine. CARB requires input circuits to be monitored for faults of this kind (1968.2, paragraph (f)(15.2.1)). In practice the cause is mostly a terminal losing contact under vibration or DEF residue in the connector. Wiggle tests with live data help; the tank sensor has its own code, P205E.

Likely causes

Symptoms

• MIL that comes and goes
• Unsteady DEF temperature in live data

Repair estimate

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

Related codes

References: law.cornell.edu, serdia.deutz.com, gsi.ext.gm.com.