Powertrain
generic / SAE
P246F
Reductant System Cold Start Performance
At cold start the SCR system is unable to begin reductant dosing within the required time. Typical cause on diesel cars in winter — frozen AdBlue in the tank or lines, failed tank heater, or a slow-warming SCR catalyst.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number4 / 6F
Possible causes
- AdBlue frozen — tank or line heater not working high
- SCR catalyst slow to reach light-off medium
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: 200–1500 €
- Estimated time: 1–4 h
- Component: adblue tank heater
- Component: adblue lines
- Component: scr catalyst
- MIL / check engine light
- emissions-relevant
- drive cycle required
Sources
References
sae:J2012