P0070 on 2020-2024 Chrysler Pacifica: Ambient Air Temp Sensor Circuit Fault Causes & Fixes

What's Unique About the 2020-2024 Chrysler PACIFICA

On the Chrysler Pacifica, the P0070 code is frequently associated with issues in the Active Grille Shutter (AGS) system, often setting a U11E9 (Lost Communication With AGS) code at the same time. [TSB #0817522REVA, TSB #S2008000132] This is because the AAT sensor and AGS share wiring harnesses or are in close proximity at the front of the vehicle, behind the bumper. Multiple manufacturer TSBs point to simple issues like loose or corroded connectors as the primary culprit, making a thorough inspection of the wiring critical before replacing any parts.

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 is on.
• Inaccurate or blank outside temperature reading on the dashboard, sometimes defaulting to -37°F or -40°F.
• Automatic air conditioning (A/C) system blows air that is not cold or doesn't regulate temperature properly.
• Seat heaters may turn on automatically if the system defaults to a very cold temperature.
• The climate control system indicator light may flash.

Most Likely Causes

1. Loose or Corroded Sensor Connector 🔴 High Probability Multiple TSBs (#S2008000147RevA, #9100248) specifically call out loose connectors and advise technicians to check this first. The sensor's location at the front of the vehicle, typically in the lower grille area, exposes the connector to moisture, road salt, and vibration, leading to corrosion.
   How to confirm: Locate the AAT sensor, which is a small, two-wire sensor usually clipped into the lower front grille area. Visually inspect the connector for looseness, damage, or green/white corrosion on the pins. Disconnect and reconnect it securely.
   Typical fix: Clean the connector pins with an electrical contact cleaner and apply dielectric grease before reconnecting to prevent future moisture intrusion. Ensure it is fully seated. Per TSB #9100248, after reconnecting, drive the vehicle for 5 minutes at over 15 mph to see if the code clears.
   Est. part cost: $0-$15
2. Damaged Wiring 🟡 Medium Probability The sensor and its wiring are located in a vulnerable position behind the front bumper, making them susceptible to damage from road debris, parking blocks, or minor front-end impacts. TSBs mention shorts and open circuits as known causes. [TSB #0817522REVA] Owners have reported this issue after minor front-end damage.
   How to confirm: Visually inspect the wiring harness leading to the sensor for any cuts, fraying, chafing, or breaks, especially where it routes near the radiator support. Use a multimeter to check for continuity between the PCM and the sensor connector and to ensure there is no short to ground or power.
   Typical fix: Repair or splice the damaged section of the wire using heat-shrink butt connectors for a durable, weather-resistant repair.
   Est. part cost: $5-$25
3. Failed Ambient Air Temperature Sensor 🟡 Medium Probability → Shop Ambient Air Temperature Sensor
   How to confirm: If the connector and wiring are confirmed to be good, the sensor itself is the likely cause. You can test it with a multimeter set to Ohms (Ω). Disconnect the sensor and measure the resistance across its two pins. The resistance should change when the sensor is warmed (e.g., with a hairdryer) or cooled. A common reading is around 10k Ohms at room temperature (77°F/25°C), and the resistance should decrease as temperature rises. An open (infinite resistance) or shorted (zero resistance) reading indicates a failed sensor.
   Typical fix: Replace the Ambient Air Temperature Sensor. It is typically held in place by a simple plastic clip and can be removed with a small flathead screwdriver.
   Est. part cost: $25-$60

Rare But Worth Checking

• Faulty Powertrain Control Module (PCM): This is extremely rare and should only be considered a potential cause after all other possibilities (sensor, wiring, connectors) have been exhaustively ruled out by a professional.

Diagnosis Steps

1. Read all fault codes using an OBD-II scanner. Note if P0073 or U11E9 are also present, as this points towards a shared wiring issue.
2. Locate the Ambient Air Temperature sensor. On the Pacifica, it is typically clipped into the lower grille area, near the bottom corner by the active grille shutters.
3. Visually inspect the sensor and its electrical connector for any signs of physical damage, corrosion, or loose connections. The front bumper location makes it prone to debris impact.
4. As per TSB #9100248, disconnect the sensor, inspect the pins for corrosion (green or white powder), clean if necessary, apply dielectric grease, and securely reconnect it. Drive the vehicle for at least 5 minutes at speeds above 15 MPH and see if the code clears.
5. If the code returns, disconnect the sensor and use a multimeter to test the wiring harness. Check for correct reference voltage (usually 5V) on one wire and a good ground on the other.
6. Test the sensor itself. With the multimeter set to Ohms (Ω), measure the resistance across the sensor's two pins. The reading should be around 10k Ohms at room temperature and should decrease as the sensor warms up (using a hairdryer) and increase as it cools. If the resistance is infinite (open) or zero (shorted), the sensor has failed.
7. If the wiring and connector are good but the sensor's resistance is incorrect or doesn't change with temperature, replace the sensor.
8. If the sensor and wiring both test good, the issue may be more complex, potentially involving the Active Grille Shutter system wiring or, in very rare cases, the PCM.

Parts You'll Likely Need

• Ambient Air Temperature Sensor (OEM #68518243AA) — This sensor is the most common part to fail in the circuit after wiring and connector issues are ruled out. It is a simple thermistor that degrades over time with exposure to the elements.
  Trusted brands: Mopar, NTK, Duralast, Standard Motor Products
  OEM price range: $40-$60
  Aftermarket price range: $25-$45

Related Codes That Often Appear With This One

• P0073 — This code for 'Ambient Air Temperature Sensor Circuit High' often appears with P0070, as they both relate to electrical faults in the same circuit. Several TSBs list them together. [TSB #9100248, TSB #S2008000147RevA, TSB #S2208000080RevA]
• U11E9 — This code for 'Lost Communication With AGS (Active Grille Shutter)' is frequently seen with P0070 on the Pacifica. The AAT sensor and AGS system share wiring harnesses, and a fault in one can affect the other, often due to a shared connector or harness damage. [TSB #0817522REVA, TSB #S2008000132]

Technical Service Bulletins (TSBs) & Recalls

• 9100248: Advises to disconnect/reconnect the sensor and drive before replacing it for P0070/P0073 codes.
• 0817522REVA: Links P0070-15 (short to battery/open) and P0070-11 (short to ground) with U11E9 (Lost Communication with AGS) due to water intrusion in a connector.
• S2008000132: Notes that P0070 and P0073 can be set along with U11E9 when the ambient air temp is displayed incorrectly.
• S2008000147RevA: Cites a loose Ambient Air Temperature connector as a cause for P0070-15 and P0073.
• S2208000080RevA: Connects a missing ambient air temperature display with DTCs P0070-15 and P0073.

Platform-Specific Known Issues

• A recurring issue documented in TSBs is a loose electrical connector at the sensor, which can cause intermittent faults. [TSB #S2008000147RevA]
• Water intrusion and corrosion in connector XY101A can cause P0070 and U11E9 codes on 2022 models built before April 25, 2022. [TSB #0817522REVA]
• The strong correlation with the Active Grille Shutter (AGS) code U11E9 suggests that any diagnosis of P0070 should also consider the health of the AGS system and its shared wiring. [TSB #S2008000132]
• Owner experiences confirm that even after replacing the sensor, the problem can persist if the underlying issue is damaged wiring from a minor front-end impact or a corroded connector pin, making a thorough circuit check essential.

Mechanic-Grade Diagnostic Values

• AAT Sensor Resistance — expected: ~10,000 Ohms (10kΩ) at 77°F (25°C). Resistance increases as temperature drops and decreases as it rises.. Failure: An open circuit (infinite resistance) or short circuit (zero or near-zero resistance) indicates a failed sensor. Resistance that does not change with temperature also indicates failure.
• AAT Sensor Connector Voltage (Key On, Engine Off) — expected: One pin should show a 5V reference signal from the PCM. The other pin is the sensor ground.. Failure: Absence of the 5V reference voltage suggests a wiring issue between the PCM and the sensor, or a faulty PCM.

Hidden / Shadow Codes Worth Checking

• P0070-15: Ambient Air Temperature Sensor Circuit - Circuit Short To Battery Or Open. This specific sub-code points to either a break in the wiring or a short to a power source. (see via A professional scan tool, such as the dealer-level wiTECH software, is needed to read these manufacturer-specific sub-codes. [TSB #0817522REVA])
• P0070-11: Ambient Air Temperature Sensor Circuit - Circuit Short To Ground. This indicates that the signal wire is making contact with a ground source. (see via A professional scan tool, such as the dealer-level wiTECH software, is needed to read these manufacturer-specific sub-codes. [TSB #0817522REVA])

Scan Tool Commands That Help

• wiTECH or equivalent professional scanner: Live Data Viewing for AAT Sensor — This is the primary function used for diagnosis. The scan tool should display the temperature the PCM is reading from the sensor. A reading stuck at an extreme value (like -40°F) while the wiring and sensor test good can point to a PCM issue. There is no specific 'reset' command; the system validates the fix after a drive cycle (5 minutes above 15 mph) as per TSB #9100248.

Wiring & Ground Locations

• Connector XY101A — A large, multi-pin front harness connector located behind the front bumper cover, near the radiator support.. TSB #0817522REVA specifically identifies this connector as a point of water intrusion and corrosion, which can cause both P0070 and U11E9 codes on 2022 models built before a specific date.
• Ground G917A — A ground point for the headlamp and dash harness, located on the chassis.. TSB #0817522REVA involves resealing this ground as part of the repair procedure for water intrusion issues that cause P0070, indicating its importance in the circuit's integrity.
• STAR Connector (Security Gateway Bypass) — On the passenger side, behind a removable plastic trim panel near the floor.. While not directly part of the AAT circuit, accessing the vehicle's full diagnostic capabilities with many aftermarket scan tools requires bypassing the Security Gateway Module (SGW) via this connector. This is necessary for deep-level diagnostics if the problem is complex.

Real Owner Repair Stories

• PacificaForums user report (2021 Chrysler Pacifica) — Check Engine Light with codes P0070 and U11E9.
  ❌ Tried (didn't work) Replacing the Ambient Air Temperature sensor.
  ✅ What actually fixed it The dealership replaced the entire front wiring harness that includes the connectors for the Active Grille Shutter (AGS) and the AAT sensor. The fault was determined to be internal corrosion or a break within the harness that was not externally visible.
• Chrysler Forum user report (Chrysler Pacifica with history of front-end damage.) — P0070 code, A/C not cold, temperature display reads -37°F.
  ❌ Tried (didn't work) Replacing the AAT sensor., Resetting the system by disconnecting the batteries.
  ✅ What actually fixed it The user suspected a wiring issue due to the vehicle's history, highlighting that replacing the sensor alone is often not the fix when wiring damage is the root cause. The resolution path points to tracing and repairing the harness.

OEM Part Supersession History

• 5149025AA → 5149265AB, which was then superseded by the current part 68518243AA. — Standard part evolution, likely for improved durability, material changes, or supplier changes.
  Heads up: All listed parts are considered interchangeable for this application. The sensor is a common component across many Stellantis vehicles.

Model Year Variations Within This Range

• 2022 models built on or before April 25, 2022: These vehicles are subject to a specific issue of water intrusion at connector XY101A, as detailed in TSB #0817522REVA. The repair involves adding zip ties and vinyl tape to better seal the connector and associated ground G917A. Models built after this date likely have an improved factory seal.
• 2021-2024 (vs. 2020): The 2021 model year introduced a significant exterior facelift, including a new front bumper and grille design. While the function of the AAT sensor is identical, its precise mounting location and the routing of the associated wiring harness may differ slightly from the pre-facelift 2020 models.