Powertrain
generic / SAE
P202B
Reductant Tank Heater Control Circuit Low
The DEF tank heater control line reads below the expected voltage — short to ground or stuck-low driver.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number– / 2B
Possible causes
- Short to ground high
- Connector pins corroded - high contact resistance low
- Harness chafing through insulation low
Symptoms
- Check engine light or NOx warning on
- AdBlue/DEF level or quality warning
- Possible no-start countdown after ignore period
- Failed emissions inspection (NOx)
Inspection / repair
- Difficulty: medium
- DIY: shop recommended
- Estimated cost: 80–700 €
- Estimated time: 0.7–2.5 h
- Component: reductant tank heater
- MIL / check engine light
- emissions-relevant
Sources
References
sae:J2012