P0073 on 2019-2023 Dodge Charger: Ambient Air Temp Sensor Circuit High Causes and Fixes

What's Unique About the 2019-2023 Dodge CHARGER

On many modern Dodge Chargers and its platform-mates (Chrysler 300, Challenger), the AAT sensor's wiring is integrated with or shares a communication bus with the Active Grille Shutter (AGS) system. A manufacturer Technical Service Bulletin (TSB S2008000132) for the 2022 model year explicitly links P0073 with a U11E9 code, which signifies lost communication with the AGS. This means that unlike many other vehicles, a P0073 code on a Charger may originate from a fault in the AGS actuator, its harness, or even the related Active Air Dam (AAD) system, not just the AAT sensor itself.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• Check Engine Light (Malfunction Indicator Lamp) is illuminated.
• Incorrect outside temperature reading on the dashboard or infotainment screen, often showing "--" or an illogical default number like -40°F.
• Automatic climate control (A/C and heat) may not function correctly, blow cold air, or may default to defrost mode.

Most Likely Causes

1. Failed Ambient Air Temperature (AAT) Sensor 🔴 High Probability → Shop Ambient Air Temperature Sensor The sensor is exposed to the elements at the front of the vehicle, making it susceptible to moisture, corrosion from road salt, and physical damage over time.
   How to confirm: Test the sensor's internal resistance with a multimeter set to Ohms. An open circuit (infinite resistance or 'OL') confirms failure. The resistance should change when heat (like from a hairdryer) is applied; if it doesn't, the sensor is bad.
   Typical fix: Replace the ambient air temperature sensor.
   Est. part cost: $20-$60
2. Damaged Wiring or Connector 🟡 Medium Probability The sensor's location behind the front grille makes its wiring vulnerable to damage from road debris, minor front-end impacts, and corrosion. The harness is often routed with the Active Grille Shutter wiring, another common area for issues.
   How to confirm: Visually inspect the wiring harness and connector for breaks, corrosion, or loose pins. Use a multimeter to check for a 5-volt reference and a good ground at the connector with the key on. If power and ground are good, use a jumper wire to connect the two pins in the harness-side connector; the temperature on your scan tool should change to a very high or very low value, confirming the wiring to the PCM is intact.
   Typical fix: Repair the broken or corroded wire(s) or replace the connector pigtail.
   Est. part cost: $15-$40
3. Active Grille Shutter (AGS) System Fault ⚪ Low Probability As per TSB #S2008000132, the AAT sensor circuit is linked to the AGS system, likely via a shared communication bus. A fault in the AGS module or its dedicated harness can interrupt the AAT signal, triggering P0073 as a secondary code.
   How to confirm: Scan the vehicle for other trouble codes. The presence of U11E9 (Lost Communication With AGS) alongside P0073 strongly points to the AGS system as the root cause. Diagnosis would then focus on the AGS actuator, wiring, and power supply.
   Typical fix: Diagnose and repair the Active Grille Shutter system. This may involve repairing its wiring harness, or replacing the entire AGS actuator/shutter assembly if the motor has failed.
   Est. part cost: $100-$450

Rare But Worth Checking

• Failed Powertrain Control Module (PCM): → Shop Engine Control Module (ECM) This is extremely rare. The PCM should only be considered after all other possibilities, including sensor, wiring, and AGS system faults, have been thoroughly ruled out.

Diagnosis Steps

1. Read all stored fault codes with an OBD-II scanner. Note if P0073 appears with U11E9, which points towards the AGS system.
2. Observe the outside temperature display on the dashboard. An incorrect reading (like -40°F) confirms a problem with the AAT sensor circuit.
3. Locate the AAT sensor. On the Dodge Charger, it is typically mounted on the front bumper support, behind the grille, specifically 'below the right horn'.
4. Visually inspect the sensor and its electrical connector for obvious damage, corrosion, or disconnected wires.
5. Disconnect the sensor. With the ignition on (engine off), use a multimeter to test the connector's terminals. One should have a 5-volt reference signal, and the other should have a good ground.
6. If power and ground are missing, inspect the wiring harness for an open circuit or break. Pay special attention to the harness near the Active Grille Shutter (AGS) assembly.
🎬 See how the updated active grille shutter wiring is routed.
7. If power and ground are present, test the sensor itself by measuring its resistance. If it reads as an open circuit (infinite resistance), replace the sensor.
8. To confirm the wiring is good, use a small jumper wire to connect the two terminals in the harness-side connector. The temperature reading on a scan tool should change drastically. If it does, the wiring is good and the sensor is bad. If it doesn't, the wiring is faulty.
9. If code U11E9 is present, prioritize diagnosis of the AGS system's power, ground, and communication circuits, as the P0073 is likely a secondary symptom.

Parts You'll Likely Need

• Ambient Air Temperature Sensor (OEM #68518243AA (supersedes 5149025AA, 5149265AB, 56042395)) — This sensor is the most common component to fail, causing the P0073 code.
  Trusted brands: Mopar, Dorman, Standard Motor Products, Duralast
  OEM price range: $45-$70
  Aftermarket price range: $20-$40
• Ambient Air Temperature Sensor Connector Pigtail — Needed if the original connector is corroded, melted, or has broken locking tabs, preventing a secure connection.
  Trusted brands: Dorman, Mopar, Various aftermarket
  OEM price range: $25-$50
  Aftermarket price range: $15-$30
• Active Grille Shutter Assembly (OEM #68405073AE (or similar)) — Only needed if diagnosis confirms the P0073 code is a symptom of a U11E9 code caused by a failed AGS motor or damaged shutters.
  Trusted brands: Mopar
  OEM price range: $400-$550
  Aftermarket price range: N/A

Related Codes That Often Appear With This One

• U11E9 — As cited in TSB #S2008000132, this code for 'Lost Communication With AGS' can appear with P0073, indicating the fault may be in the Active Grille Shutter system or its shared wiring.
• P0072 — This code indicates the opposite fault, 'Circuit Low,' which points to a short circuit to ground instead of an open circuit.
• P0070 — This is a general fault code for the Ambient Air Temperature Sensor Circuit.

Technical Service Bulletins (TSBs) & Recalls

• S2008000132: Malfunction Indicator Lamp Illuminated. U11E9 Lost Communication With AGS. Ambient Air Temp Incorrectly Displayed. P0070 And P0073 Set For Ambient Air Temp Sensor
• 18-044-26: ...P0073-00 - Ambient Air Temperature Sensor Circuit 'A' High.
• TT9002834: Tech Tip requesting data gathering for Active Grille Shutter codes including U11E9.

Platform-Specific Known Issues

• TSB #S2008000132 notes that on 2022 models, P0073 can be triggered by a loss of communication with the Active Grille Shutter (AGS), often setting code U11E9 simultaneously.
• Chrysler Tech Tip #TT9002834 shows that the manufacturer is actively gathering data on vehicles that set codes P1D73, P05A5, or U11E9 related to the Active Grille Shutter, indicating this is a known area of concern.
• TSB #18-044-26 confirms that P0073-00, defined as 'Ambient Air Temperature Sensor Circuit 'A' High,' is a recognized fault code for the 2019 model year.

Mechanic-Grade Diagnostic Values

• AAT Sensor Resistance vs. Temperature — expected: Resistance is inversely proportional to temperature. Example values: 32°F (0°C) ≈ 32,650 Ohms; 77°F (25°C) ≈ 10,000 Ohms; 100°F (38°C) ≈ 5,774 Ohms.. Failure: An open circuit ('OL' on a multimeter) or a resistance value that does not change with temperature indicates a failed sensor.
• AAT Sensor Signal Voltage at Connector — expected: With the sensor disconnected and ignition on, one pin should have a 5V reference from the PCM/TIPM. When connected, the signal voltage should be between 0.5V (hot) and 4.5V (cold).. Failure: A P0073 'Circuit High' fault is typically set when the PCM sees a voltage above 4.5V or 4.9V, which occurs when the circuit is open (sensor unplugged or failed internally).

Scan Tool Commands That Help

• Witech (or equivalent professional scanner): AGS Actuator Test / Active Command — If P0073 is present with U11E9, this command is used to bidirectionally control the Active Grille Shutters. If the shutters do not respond to the command, it confirms a fault within the AGS system (actuator, wiring, or power), which is the likely root cause of the P0073 code in this scenario.

Wiring & Ground Locations

• (G31) AAT Signal / (G931) Sensor Ground — These are not physical locations but circuit identifiers within the wiring harness between the AAT sensor and the Totally Integrated Power Module (TIPM) or PCM.. The AAT sensor uses a dedicated sensor ground wire that runs back to the control module; it does not ground to the chassis near the sensor. A common diagnostic error is looking for a bad chassis ground. The fault is almost always in the sensor itself or the two wires running back to the module.
• Main Chassis Ground Stud — Under the hood, near the front power distribution box, there is a dedicated stud for grounding jump-start cables and accessories.. While the AAT sensor does not ground here directly, a poor main body or engine ground can cause widespread electrical issues. Verifying this ground is tight and corrosion-free is a good preliminary step in any electrical diagnosis.

Real Owner Repair Stories

• Multiple YouTube repair videos (2012 Dodge Charger 5.7L (similar procedure for 2019-2023 models)) — Check engine light was on, A/C was blowing hot air, and the outside temperature display read an illogical -40°F.
  ❌ Tried (didn't work) Most videos proceed directly to sensor replacement as the first step, as it is the most common failure.
  ✅ What actually fixed it Replacing the ambient air temperature sensor. One technician noted that to access the sensor, the entire front bumper does not need to be removed; a DIYer can remove the upper radiator sight shield and plastic clips to pull the top of the bumper cover forward enough to reach the sensor, which is located near the passenger side horn.

When the Usual Fixes Don't Work

• While the most common fix for P0073 is replacing the ambient air temperature sensor, a significant number of cases on this specific platform are not resolved by a sensor replacement. If the code returns after a new sensor is installed, and especially if code U11E9 is also present, the root cause is very likely a fault in the Active Grille Shutter (AGS) system. As noted in TSB S2008000132, a loss of communication with the AGS module will cause the AAT sensor to stop reporting, triggering P0073 as a secondary, symptomatic code. In these instances, all diagnostic efforts must be shifted to testing the AGS actuator motor, its wiring harness for damage near the shutters, and its power/ground supply.

OEM Part Supersession History

• 56042395, 5149025AA, 5149265AB → 68518243AA — The reason for supersession is not officially documented, but it typically involves improvements to materials, weather sealing, or internal electronics for better durability and accuracy.
  Heads up: There are no known incompatibilities; the newest part number (68518243AA) is the correct service replacement for all previous versions on this platform.

Model Year Variations Within This Range

• 2022+: TSB S2008000132 specifically highlights the link between P0073 and U11E9 (AGS communication loss) for the 2022 model year, indicating a potential software or hardware revision that makes this correlation more common or formally recognized.
• All years with option: Models equipped with the Active Air Dam (AAD) have an additional module on the same communication bus as the AAT and AGS. A fault in the AAD system, its wiring, or its module could also potentially cause a communication breakdown that results in a P0073 code.