Fix P0452: Mechanic’s solutions that WORKED

The code P0452: “Evaporative Emission Control System Pressure Sensor Low Input” indicates an issue with the pressure sensor in your car’s evaporative emission control system, specifically reporting that the sensor’s input signal is too low.

P0452 quick overview

Meaning	P0452: Evaporative Emission Control System Pressure Sensor Low Input
Is it serious?	Moderately serious, as it can affect the vehicle’s emissions control system and may lead to fuel odor or decreased fuel efficiency.
Possible causes	– Faulty or damaged fuel tank pressure sensor – Loose, damaged, or corroded wiring or connectors to the sensor – Issues with the EVAP canister or related components – Leaks in the EVAP system hoses or fittings – Improperly seated or faulty gas cap
How to diagnose?	Inspect the Fuel Tank Pressure Sensor: Check for visible damage or disconnection. Check Wiring and Connectors: Ensure all connections to the sensor are secure and free from corrosion. Examine EVAP System Components: Look for damage or leaks in the EVAP canister, hoses, and fittings. Test Sensor Functionality: Use diagnostic tools to test the pressure sensor’s operation. Perform a Smoke Test: Conduct a smoke test to detect any hard-to-find leaks in the EVAP system. Check Gas Cap: Ensure that the gas cap is properly sealed and not causing a leak.

This system is designed to capture and recycle fuel vapors, preventing them from escaping into the atmosphere. When this code is set, it means the sensor that monitors the pressure of these vapors isn’t sending the expected signal.

How to fix P0452 – learn from mechanics

I looked into P0452 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.

Case #1: Dodge

Vehicle Information

• 2003 Dodge Ram 2500 5.7L

Issue + Repair History

• MIL (Malfunction Indicator Lamp) on
• Codes: P0455 (evap leak), P0452 (evap leak)
• Replaced gas cap

Suggested Fixes

• Check hoses at the canister for splits
• Run forced leak monitor test; check for a bad leak detection pump
• Inspect the purge canister hoses and connections
• Look for cracks in the vacuum harness off the canister
• Consider replacing the leak detection pump if testing is more time-consuming
• Check the purge valve for charcoal particles

Final Fix

• Found a cracked hose running from the leak detection pump to the charcoal canister
• Replaced the hose, cleared the code, resolving the issue

Case #2: Chevrolet

Vehicle Information

• 2001 Chevrolet Silverado 1500 4.3L

Issue + Repair History

• MIL (Malfunction Indicator Lamp) on
• Codes: P0107 (MAP/BARO voltage low), P0452 (EVAP sensor reading low)
• Replaced MAP EVAP sensor and gas cap

Suggested Fixes

• Check the ENG 1 fuse, as the two sensors might share a common feed
• Inspect for green corrosion on the fuel pump connectors
• Measure voltage at the MAP sensor connector
• Check 5-volt reference at PCM and all sensors using it
• Look for bad ground or power problem
• Consider a shorted sensor or circuit pulling down the 5 volts
• Use volt drop method to check ground circuit

Final Fix

• The problem was due to a rat chewing some wires under the relay center, which was initially missed
• Repairing the chewed wires resolved the issue

Case #3: Ford

Vehicle Information

• 2008 Ford Escape XLT 2.3L

Issue + Repair History

• Original code: P0454 (fuel tank pressure sensor readings fluctuating)
• Replaced fuel tank pressure sensor, resolved P0454
• New issue: Code P0452 present (voltage not returning fast enough to 2.5V)

Suggested Fixes

• Blow out all lines in the system to check for blockages
• Replace vent solenoid
• Check if scan tool shows FTP sensor low voltage
• Consider the reliability of aftermarket parts for the FTP sensor
• Test for broken or blocked charcoal canister
• Check FTP sensor readings with KOEO (Key On Engine Off), observe voltage changes with gas cap removed and applying air pressure to the gas tank

Final Fix

• Found water in the vent valve filter, originating from a hole in the filler neck below the gas cap
• Experienced additional code P0450 (loss of 5-volt reference to fuel tank pressure sensor)
• Cleaned the connector at the computer and adjusted the harness
• Restored the 5-volt reference, which resolved the issue
• No recurrence of the light a week later after speaking with the customer

Case #4: Kia

Vehicle Information

• 2010 Kia Soul Sport 2.0L

Issue + Repair History

• Initial problems: High revving then dying, codes P0107 (MAP sensor low input) and P0449 (Canister closed valve)
• After repairs: Stalling after a few minutes of driving, won’t restart unless MAP sensor is unplugged
• New codes: P0107, P0449, and P0452
• Replaced MAP sensor and canister close valve, cleaned throttle body and Idle Control valve

Suggested Fixes

• Monitor reference voltage during failure event
• Isolate and load test MAP and ECM wires
• Check for other sensors sharing the 5V reference
• Inspect wiring to the MAP sensor
• Consider the possibility of a faulty new MAP sensor

Final Fix

• Utilized the KDS scan tool for management system access
• Performed a PCM recalibration
• This resolved the stalling issue and cleared the check engine light

Other Test Results

• Resistance check: 0 ohm
• Voltage reference: 5 volts
• Smoke test: No leak detected

Case #5: Jaguar

Vehicle Information

• 1998 Jaguar XK8 4.0L

Issue + Repair History

• Fuel odor inside the car
• Code: P0452 (Evap system pressure)
• Checked fuel lines, cap, tank, everything appears normal

Suggested Fixes

• Check the gas cap for proper sealing
• Inspect for any previous body work, especially near the fuel system
• Examine the evaporative pressure sensor on top of the fuel tank
• Look for a split plastic hose coming from the filler neck to the EVAP canister
• Verify that the vent valve is closed when the engine is running

Final Fix

• Found a small leak in the fuel drain hose, which leaked fuel into the trunk well, causing the odor
• Replaced the Evaporative pressure sensor to fix the P0452 code

Advice	Diagnostic Step Description
Check Gas Cap and Sealing	Inspect the gas cap for proper sealing as a poorly sealed cap can trigger EVAP system codes.
Inspect Fuel Tank Pressure Sensor	Examine the fuel tank pressure sensor for faults or leaks, as it directly impacts EVAP system pressure readings.
Examine EVAP System Hoses and Canisters	Look for any splits, cracks, or blockages in hoses leading to and from the EVAP canister.
Investigate Prior Body Work	Check for past body repairs that could have affected the EVAP system, particularly in the area of the fuel tank or filler neck.
Verify Vent Valve Operation	Ensure the vent valve is functioning correctly and closes when the engine is running, as it plays a crucial role in the EVAP system.
Conduct a Smoke Test	Perform a smoke test to identify any small or hidden leaks in the EVAP system.
Monitor Fuel Tank Pressure Sensor Readings	Use diagnostic tools to monitor the pressure sensor’s readings for any irregularities that may indicate a malfunction.