A fault code doesn’t yet mean the unit or sensor itself is faulty: often it’s the plug and connector leading to it.
What you can do yourself
- The control unit sees that the AdBlue isn’t cleaning the exhaust well: most often poor-quality or diluted AdBlue has been added.
- Drain the AdBlue and fill with proper fluid — from a sealed container or a trusted filling station.
- If power or speed is already limited, this is a protection required by the Euro standards, not an engine breakdown. Drive calmly to a service centre.
- Do not disconnect the sensors and the AdBlue system or tamper with the tachograph — it is a violation that is fined, and the fault won’t go away.
Stop and don’t drive on if:
- The Check Engine light is flashing
- The temperature gauge is in the red or the overheating light is on
- The red oil pressure light is on
- Smoke from under the bonnet, a burning or petrol smell
- Strong jerking, knocking from the engine, or the car barely moves
Add the FMI — the second number of the code. It shows what exactly is wrong with the parameter.
Source: Navistar IK0700079: DEF Tank Heater, DEF Quality (static.nhtsa.gov, MC-10162033)
The explanation comes from the error code reference in the AvtoElektrik PRO app.