P202A code meaning
Reductant Tank Heater Control Circuit/Open
Powertrain system Generic code P20xx codes Check engine light
What P202A means
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.
P202A at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P202A
- Malfunction indicator lamp on
- In frost, DEF system warning and inducement countdown
Common causes of P202A
- Most likelyTank heater element burnt through
- PossibleLoose or burnt connector at the tank, or blown heater fuse
- Less likelyInterrupted wire between control unit and tank
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Reductant tank heaterReductant tank harness
What each part of P202A means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 0 | Area: fuel and air metering and auxiliary emission controls. |
| 2A | The exact fault in that area. |
What to do next
- Note P202A and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P202A
What does P202A mean?
P202A means "Reductant Tank Heater Control Circuit/Open". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with P202A?
Drive gently and only to a workshop. With P202A the car can go into limp mode (reduced power) to protect itself.
Will P202A fail an emissions test?
Yes, it can. P202A is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P202A to fix?
Difficulty: medium. A typical repair takes 0.5 to 4 hours of work. This is a job for a workshop.
Will P202A clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.