Lost Communication With Ammonia Sensor
Table of contents
U12A4 CHRYSLER Possible Causes
- Faulty Ammonia Sensor Module
- Ammonia Sensor Module harness is open or shorted
- Ammonia Sensor Module circuit poor electrical connection
- Faulty Powertrain Control Module (PCM)
How do I fix code U12A4 CHRYSLER?
Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector’s pins.
Cost of diagnosing the U12A4 CHRYSLER code
The cost of diagnosing the U12A4 CHRYSLER code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle’s make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.
Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
U12A4 CHRYSLER Description
The Ammonia (NH3) Sensor is located in the middle of the aftertreatment SCR Catalyst and is used to measure the ammonia concentration in the aftertreatment system. The Ammonia Sensor Module is a smart device that performs its own internal diagnostics, as well as diagnostics on the sensor and reports malfunctions back to the Powertrain Control Module (PCM) via the J1939 data link. The PCM will illuminate the Malfunction Indicator Lamp (MIL) after the diagnostic runs and fails in one drive cycle.