Engine-Codes - Jeep - U12A4 Jeep

U12A4 Jeep Code - Lost Communication With Ammonia Sensor

- Code Popularity: 353 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 3/3
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What are the Possible Causes of the DTC U12A4 Jeep?

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other 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)
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How to Fix the DTC U12A4 Jeep?

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 pins.

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What is the Cost to Diagnose the Code?

Labor: 1.0

The cost to diagnose the U12A4 Jeep code is 1.0 hour of labor. The diagnosis time and labor rates at auto repair shops vary depending on the location, make and model of the vehicle, and even the engine type. Most auto repair shops charge between $75 and $150 per hour.

What are Code Possible Symptoms?

  • Engine Light ON (or Service Engine Soon Warning Light)

What Does the U12A4 Jeep Code Mean?

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.

U12A4 Jeep Code - Lost Communication With Ammonia Sensor

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