What Does P20C2 Mean?
The PCM has determined that reductant heater C is not performing within expected parameters. The heater may be drawing incorrect amperage, heating inefficiently, or failing to reach proper operating temperature.
Common Causes
40%
Partially degraded heater element with increased resistance
25%
High resistance in connections or wiring reducing heater efficiency
15%
Inadequate voltage supply due to battery or charging system issues
12%
Malfunctioning temperature sensor providing inaccurate readings
8%
Control module with degraded driver circuit output
Diagnostic Steps
1
Step 1: Use amp clamp to measure heater C current draw during operation and compare to specifications
2
Step 2: Measure heater element resistance when cold and verify it falls within acceptable range
3
Step 3: Perform voltage drop test on all connections and wiring while heater is operating under load
4
Step 4: Verify battery and charging system voltage meets minimum requirements during heater operation
5
Step 5: Monitor temperature sensor readings during heater cycle to confirm accurate feedback to PCM
Estimated Repair Cost
$200 - $750
Parts + labor, varies by vehicle and location
The PCM has determined that reductant heater C is not performing within expected parameters. The heater may be drawing incorrect amperage, heating inefficiently, or failing to reach proper operating temperature.
The most common cause of P20C2 (Reductant Heater "C" Control Circuit Performance) is: Partially degraded heater element with increased resistance
Typical repair costs for P20C2 range from $200 to $750, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to drive under normal conditions. Degraded heater performance may lead to DEF system problems in cold climates, potentially resulting in emissions system failure and engine power limitations.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P20C2 to identify the root cause.
OBDHut Mobile App
Scan codes directly from your car with the OBDHut app.
Coming Soon
Quick Info
Category
Powertrain
System
Emissions - Selective Catalytic Reduction (SCR)
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
