OBD-II code · Powertrain (generic, extended)
P2064 Reductant/Regeneration Supply Control Circuit High
Reductant/regeneration supply control line stuck high — short to B+ or open ground. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
Is it safe to drive with P2064?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyShort to B+
- Less likelyConnector pins corroded - high contact resistance
- Less likelySupply wire pinched against B+ source
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)
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.8–3 h
- Emissions test
- Likely to fail
- Parts involved
- Reductant Supply Pump
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.