P202AReductant Tank Heater Control Circuit/Open
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- DEF freezes at about −11 °C, so the tank carries an electric, often PTC-type heater that thaws enough fluid for dosing after a cold start. P202A covers the control circuit of that heater with the emphasis on an open circuit: when commanded on, practically no current flows. Volkswagen documents it on the 2014 Touareg 3.0 TDI (CNRB) and judges the element by its conductance: during heating a value of 0.10 S or less, roughly 10 Ω or more, sets the code. Typical are a broken element, a burnt or loose connector at the tank, a blown fuse or an interrupted wire. With the heater dead, frozen DEF cannot be dissolved, so in winter the system soon reports it cannot dose and may begin the inducement countdown. P202B and P202C separate a weak or excessive heater current from this complete interruption.
- What you may notice
- Malfunction indicator lamp on
- In frost, DEF system warning and inducement countdown
- Likely causes
- LikelyTank heater element burnt through
- PossibleLoose or burnt connector at the tank, or blown heater fuse
- RareInterrupted wire between control unit and tank
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €50 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.