OBD-II code · Powertrain (generic, extended)
P24E4 NH3 Sensor Circuit High
Same as P24E1 with the signal voltage above the plausible range. 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 P24E4?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySignal shorted to supply
- Less likelyConnector pins corroded - high contact resistance
- Less likelySupply wire pinched against B+ source
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–3 h
- Emissions test
- Likely to fail
- Parts involved
- Nh3 Sensor
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.