OBD-II code · Powertrain (generic, extended)
P24EB NH3 Sensor Supply Voltage Circuit Low
The NH3 slip sensor supply voltage drops below the lower limit. Usually a partial short to ground in the supply line, an undersized ground path with high resistance, or an internal supply collapse in the SCR/dosing module. Sensor output is held invalid until the supply recovers.
Is it safe to drive with P24EB?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySupply line shorted to ground
- PossibleHigh-resistance ground at the SCR module
- Less likelyConnector pins corroded - high contact resistance
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.5–2 h
- Emissions test
- Likely to fail
- Parts involved
- Nh3 Sensor, Supply Wiring, Dosing Module
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.