P0452 on 2021 Jeep Grand Cherokee: EVAP Pressure Sensor Low Input Causes & Fixes

What's Unique About the 2021-2021 Jeep GRAND CHEROKEE

The 2021 model year is a transition period for the Grand Cherokee, including both the end of the 4th generation (WK2) and the introduction of the all-new 5th generation (WL). While the code's meaning is the same, the repair varies significantly. For the WK2, the FTP sensor is often available as a separate part. For the newer WL, the sensor is frequently integrated into the entire fuel pump module, meaning the whole unit must be replaced to fix the sensor. Unlike many vehicles where this code could be a simple loose gas cap, Grand Cherokees from this era feature a capless fuel filler system, ruling out that easy fix. The most common repair requires dropping the fuel tank to access the sensor, as there is no under-seat access panel, making the job more complex than on other vehicles.

Diagnostic Flowchart

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

Generation note: The 2021 model year includes two distinct generations: the Grand Cherokee (WK2 platform, 2011-2021) and the all-new Grand Cherokee L (WL platform, 2021-present). The standard two-row Grand Cherokee for 2021 was still the WK2. While the EVAP system principles are similar, specific part locations, part numbers, and repair procedures vary significantly. For the WK2, the sensor may be replaceable on its own. For the WL, the sensor is often part of the larger, more expensive fuel pump module assembly. Always verify parts by VIN.

Symptoms You May Notice

• Check Engine Light is on
• Possible faint fuel odor (rare)
• Inability to pass a state emissions inspection

Most Likely Causes

1. Faulty Fuel Tank Pressure (FTP) Sensor 🔴 High Probability Sensors can fail electronically over time, sending a signal that is permanently low, regardless of actual tank pressure. On the WL platform, the sensor is often integrated with the fuel pump module, meaning a failure requires replacing the entire assembly.
   How to confirm: Use a scan tool to monitor the FTP sensor's voltage or pressure reading. If the reading is stuck at an abnormally low value (e.g., below 0.5 volts, often near 0V) and does not change when the fuel filler is opened, 🎬 See how to test and replace a faulty pressure sensor. the sensor is likely bad.
   Typical fix: For WK2 models, replace the Fuel Tank Pressure sensor. For WL models, you may need to replace the entire fuel pump/level unit module. Both require dropping the fuel tank for access. 🎬 Watch: Step-by-step guide on dropping the tank and replacing the unit.
   Est. part cost: $50-$90 for sensor (WK2), $300-$500+ for fuel pump module (WL)
2. Wiring or Connector Issue 🟡 Medium Probability The wiring harness leading to the fuel tank is exposed to road debris, moisture, and potential rodent damage. This can cause corrosion in the connector or damage to the wires (short to ground, open circuit), interrupting the signal. A common area to inspect is the harness running along the frame rail and the main connector located in front of the fuel tank on the driver's side.
   How to confirm: Visually inspect the wiring and connector at the FTP sensor for damage, corrosion, or loose pins. Perform a continuity test and check for 5V reference voltage and a good ground at the connector with a multimeter.
   Typical fix: Repair the damaged section of wiring or clean/replace the connector.
   Est. part cost: $5-$50
3. Incorrectly Assembled Purge Tube (WL models only) ⚪ Low Probability TSB 18-061-22 was issued for some 2021-2022 Grand Cherokee (WL) models for an incorrectly assembled purge flow tube inside an elbow, which can trigger P0452 along with P0441.
   How to confirm: This applies specifically to certain WL models and should be investigated by a dealer referencing TSB 18-061-22. It involves a physical inspection of the purge tube's position.
   Typical fix: Reposition the purge tube inside the elbow as per the TSB instructions.
   Est. part cost: $0 (if under warranty)

Rare But Worth Checking

• Faulty Powertrain Control Module (PCM): This is extremely rare. The PCM should only be considered after all other possibilities, including wiring, sensors, and applicable TSBs, have been exhaustively tested and ruled out. Sometimes a PCM software update (flash) can resolve false codes.

Diagnosis Steps

1. Connect an OBD-II scanner and confirm P0452 is the active code. Check for any other related codes, such as P0441.
2. Using the scanner's live data function, observe the reading for the Fuel Tank Pressure sensor. The voltage should typically be around 2.5V at atmospheric pressure. A reading near 0V or a very low, unchanging value points towards a sensor or circuit issue.
3. Inspect the capless fuel filler door to ensure it is closing and sealing properly.
4. Raise the vehicle and locate the FTP sensor on top of the fuel tank. Visually inspect the entire wiring harness leading to the tank for any signs of corrosion, chafing, or rodent damage. Pay close attention to where the harness may rub against the frame or suspension components.
5. Disconnect the sensor and check the connector for 5-volt reference and a good ground using a multimeter. Check the signal wire for a short to ground.
6. If the wiring and voltages are correct, the FTP sensor (or the fuel pump module on WL models) is the most likely culprit.
7. If codes P0452 and P0441 are present on a WL model, consult TSB 18-061-22 for the purge tube inspection procedure.
8. If replacing the sensor/module does not resolve the code, further testing of the PCM circuit is required.

Parts You'll Likely Need

• Fuel Tank Pressure Sensor (for WK2) (OEM #68408023AB (Verify with VIN)) — This sensor is the most common point of failure for a P0452 code on the WK2 platform, as it directly provides the voltage reading that the PCM has identified as too low.
  Trusted brands: Mopar, Bosch, NTK
  OEM price range: $50-$80
  Aftermarket price range: $25-$50
• Fuel Pump/Level Unit Module (for WL) (OEM #68541368AC (Verify with VIN)) — On the newer WL platform, the FTP sensor is often not sold separately and is integrated into the main fuel pump module. A sensor failure requires replacing the entire assembly.
  Trusted brands: Mopar
  OEM price range: $350-$550
  Aftermarket price range: N/A (often OEM only for new models)

Related Codes That Often Appear With This One

• P0441 — P0441 (EVAP Purge System Performance) is mentioned alongside P0452 in TSB 18-061-22 for 2021-2022 WL models due to a potential physical issue with a purge tube. This suggests that on the WL platform, if these two codes appear together, this TSB should be investigated first.

Technical Service Bulletins (TSBs) & Recalls

• TSB #18-061-22 (2022-03-29): Applies to 2021-2022 Grand Cherokee (WL). Addresses P0452 and P0441 caused by an incorrectly assembled purge flow tube.
• TSB #25-002-21 REV. A: Applies to 2021-2022 Grand Cherokee L (WL) and involves a PCM software update for various DTCs. While not listing P0452 specifically, it shows a precedent for software fixes on this platform.

Platform-Specific Known Issues

• A Technical Service Bulletin (TSB 18-061-22) was issued for some 2021-2022 Grand Cherokee WL models linking P0452 with P0441. The cause is an incorrectly positioned purge flow tube. If both codes are present, this should be the first check.
• On the Grand Cherokee L (WL), the FTP sensor is typically not sold separately from the fuel pump module. A forum user on jeepgarage.org with a 2018 WK2 reported a dealer repair cost of over $1,200 for a similar job, confirming the high labor cost due to dropping the fuel tank.

Mechanic-Grade Diagnostic Values

• FTP Sensor Signal Voltage (Key On, Engine Off, Fuel Cap Off) — expected: ~2.5 Volts (at atmospheric pressure). Failure: A reading near 0V or below 0.22V indicates a short to ground or faulty sensor, triggering P0452.
• FTP Sensor Operating Range — expected: 0.5V (high vacuum) to 4.5V (pressure). Failure: A signal that is stuck low and does not change when vacuum is applied or pressure changes.
• FTP Sensor Connector - Reference Voltage — expected: 5.0 Volts. Failure: Significantly less than 5.0V indicates a problem with the PCM or the wiring from the PCM.

Scan Tool Commands That Help

• wiTECH or equivalent professional scan tool: EVAP System Test / Purge Solenoid Activation — After confirming the baseline voltage is plausible, a technician can use a bidirectional scan tool to command the EVAP purge or vent solenoid to change states. While monitoring the live FTP sensor voltage, this forces a pressure change in the system. If the voltage reading doesn't change accordingly, it helps confirm the sensor is faulty and not responding, even if the wiring is good.

Wiring & Ground Locations

• Fuel Tank Harness Connector — On the driver's side of the vehicle, in front of the fuel tank. This is the main connector for the fuel pump module and FTP sensor before the harness goes up over the tank.. This connector is a critical point for testing. A technician can disconnect it to check for the 5V reference, ground, and signal continuity back to the PCM without having to drop the fuel tank initially. Corrosion or damage at this accessible point can cause the P0452 code.

"I Checked Everything" — The Actual Cause

• A technician may find 0 volts on the 5V reference wire at the FTP sensor connector and assume a wiring fault or bad PCM. However, the actual cause could be a blown fuse that supplies power to the EVAP system components. On some vehicle platforms, a dedicated 'emissions' fuse in the underhood fuse block powers the 5V reference circuit for multiple EVAP sensors. If this fuse blows, it will cause a P0452 and potentially other EVAP codes, but a smoke test would be clean and the wiring harness itself would check out fine on a continuity test.

OEM Part Supersession History

• 68541368AA, 68541368AB → 68541368AC — Standard part revision and improvement by the manufacturer.
  Heads up: The newer part number (AC) is the correct replacement for the older AA and AB versions for the WL Grand Cherokee.