What Does P205D Mean?
The DEF tank temperature sensor circuit voltage is reading higher than the maximum acceptable threshold. This typically indicates an open circuit, short to voltage, or a sensor reading excessively high temperatures.
Common Causes
35%
Open circuit in sensor wiring or poor connection
30%
Failed DEF tank temperature sensor reading open circuit
20%
Corroded or loose sensor connector terminals
10%
Short to voltage in sensor signal wire
5%
Poor ground connection at sensor or ECM
Diagnostic Steps
1
Step 1: Disconnect sensor and measure voltage at harness connector; should read near 5V reference voltage
2
Step 2: Check sensor connector terminals for corrosion, bent pins, or loose fit
3
Step 3: Measure sensor internal resistance; open circuit indicates failed sensor
4
Step 4: Wiggle test wiring harness while monitoring live data for signal dropout
5
Step 5: Replace sensor if resistance is out of spec or shows open circuit condition
Estimated Repair Cost
$150 - $500
Parts + labor, varies by vehicle and location
The DEF tank temperature sensor circuit voltage is reading higher than the maximum acceptable threshold. This typically indicates an open circuit, short to voltage, or a sensor reading excessively high temperatures.
The most common cause of P205D (Reductant Tank Temperature Sensor Circuit High) is: Open circuit in sensor wiring or poor connection
Typical repair costs for P205D range from $150 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to drive temporarily but performance may be limited. Extended driving may trigger DEF system lockout preventing engine restart.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P205D to identify the root cause.
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Quick Info
Category
Powertrain
System
Emissions Control (SCR/DEF System)
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
