P20C2 on 2014-2016 Jeep Grand Cherokee — Reductant Heater "C" Control Circuit Performance
1 vehicles · 1 makes
Most Reported On
P20C2 is an OBD-II diagnostic trouble code meaning “Reductant Heater "C" Control Circuit Performance.” A generic diesel emissions code on SCR-equipped vehicles (Ford, RAM/Cummins, GM Duramax, Mercedes, VW and many medium/heavy-duty diesels). The powertrain control module commanded the "C" diesel exhaust fluid (DEF) heater on and the measured circuit voltage or current fell outside the expected range. The letter "C" designates one of several heaters on vehicles with multiple DEF heaters - typically the tank, supply lines, or injector hose. These heaters keep DEF from freezing or crystallizing in cold weather; when one underperforms the SCR system can stop dosing. Expect a warning light and, if ignored, a speed limit or no-restart derate. This code is most commonly reported on 2014-2016 Jeep Grand Cherokee.
Common Causes
Diagnostic Tools
This is a powertrain code, so a basic OBD-II reader can read it. These read P20C2.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple code reader for engine (P) codes on many compatible OBD-II vehicles. It does not support every vehicle or hybrid/EV application, and it does NOT read body, chassis or network codes; confirm exact-vehicle compatibility before buying.
- Read & clear engine (P) codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth scanner with a companion app that reads beyond the engine module — ABS, SRS and transmission — plus manufacturer-specific codes on many vehicles.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X V3.0 Elite OBD-II Scanner
by LAUNCH
Handheld scanner covering the four major systems (engine, transmission, ABS, SRS) with live data streaming and graphing.
- Engine, transmission, ABS, SRS diagnostics
- Live data stream & graphing
- AutoVIN for vehicle identification
- Free lifetime updates via Wi-Fi
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level tablet with all-system coverage and bi-directional control, so you can command a module rather than only read it.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
What you can do yourself, and what needs a shop
Reading the code, clearing it, and watching whether it returns is a driveway job with the right scanner. These steps are not:
- Module programming or software updates — needs the manufacturer software or a J2534 pass-through with a paid subscription.
- Replacing a control module — most are VIN-programmed and immobilizer-registered, so a new one does nothing until it is coded to your car.
- Airbag/SRS component work — a stored fault can deploy a live device.
If the vehicle is still under warranty, check for an open recall or technical service bulletin before buying anything — the repair may already be covered.
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FAQ
What does P20C2 mean?
P20C2 stands for "Reductant Heater "C" Control Circuit Performance." A generic diesel emissions code on SCR-equipped vehicles (Ford, RAM/Cummins, GM Duramax, Mercedes, VW and many medium/heavy-duty diesels). The powertrain control module commanded the "C" diesel exhaust fluid (DEF) heater on and the measured circuit voltage or current fell outside the expected range. The letter "C" designates one of several heaters on vehicles with multiple DEF heaters - typically the tank, supply lines, or injector hose. These heaters keep DEF from freezing or crystallizing in cold weather; when one underperforms the SCR system can stop dosing. Expect a warning light and, if ignored, a speed limit or no-restart derate.
What are the most common causes of P20C2?
The most common causes of P20C2 are: Failed DEF tank or supply-line heater element (heater C), Corroded or damaged connector at the DEF header/tank unit, Chafed, open, or shorted wiring in the heater control circuit, Failed heater relay or blown fuse feeding the heater circuit, Faulty DEF header assembly, Failed ECM/PCM heater driver. The specific cause varies by vehicle.
How much does it cost to fix P20C2?
Repair costs vary widely depending on the root cause and vehicle.
Which vehicles are affected by P20C2?
Au7o has documented P20C2 across 1 vehicle models from 1 manufacturers: Jeep.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.