What Does P2043 Mean?
The reductant temperature sensor is providing readings that are implausible or outside expected range compared to other temperature sensors. The sensor may be reading too high or low relative to engine or ambient temperature.
Common Causes
35%
Degraded temperature sensor with drift or calibration error
25%
Poor thermal contact between sensor and DEF fluid
20%
Contaminated DEF fluid affecting heat transfer properties
15%
High resistance in sensor circuit affecting readings
5%
DEF tank insulation or heater system malfunction
Diagnostic Steps
1
Step 1: Compare DEF temperature reading to ambient and engine coolant temperature using scan tool
2
Step 2: Monitor temperature sensor values during warm-up cycle for reasonable rate of change
3
Step 3: Test sensor resistance at various temperatures and compare to specifications
4
Step 4: Inspect sensor installation depth and seal condition in DEF tank
5
Step 5: Check DEF fluid quality and test for contamination or degradation
Estimated Repair Cost
$200 - $550
Parts + labor, varies by vehicle and location
The reductant temperature sensor is providing readings that are implausible or outside expected range compared to other temperature sensors. The sensor may be reading too high or low relative to engine or ambient temperature.
The most common cause of P2043 (Reductant Temperature Sensor Circuit Range/Performance) is: Degraded temperature sensor with drift or calibration error
Typical repair costs for P2043 range from $200 to $550, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Incorrect temperature readings may prevent DEF system operation in cold weather or cause improper dosing. Vehicle may enter reduced power mode and display derate warnings.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P2043 to identify the root cause.
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Quick Info
Category
Powertrain
System
Emissions Control (SCR)
Difficulty
Type
Generic (SAE)
Recommended Tools
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