This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.
P1443 is an OBD-II Code that refers to Evaporative Emission System Control Valve Low/No Flow (Ford, Infiniti, Jaguar, Lincoln, Mercedes, Mercury, Saab)
A P1443 code is a manufacturer specific diagnostic trouble code that occurs with Ford, Infiniti, Jaguar, Lincoln, Mercedes, Mercury, Saab make vehicles when the PCM/ECM detects that the evaporative emission system control valve does not have proper flow. The Evaporative Emissions Control System (EVAP) is a device that captures fuel vapors and prevents them from entering the environment. The Engine Control Module (ECM) is used to interpret the amount of fuel pumped and delivered by the gasoline engine. It also monitors various sensors, switches, and valves.
A P1443 code is set and stored when the ECM/PCM detects that the evaporative emissions system control valve has an issue with low or no flow.
Common causes for this code include:
- A shorted, open, or otherwise damaged circuit
- Faulty purge control valve
- A faulty circuit in the EVAP purge control valve is causing this problem
- The fuel tank pressure sensor is faulty
- The incoming hose or connectors between the purge control valve and the fuel tank pressure sensor (FTPS) are clogged
- Faulty or malfunctioning charcoal canister
- Dislodged or broken vacuum lines
- Malfunctioned or damaged PCM
The symptoms of a P1443 code are:
- Illuminated Check Engine Light
- Vehicle may fail emissions test
- Bad fuel efficiency
- Strong fuel odors are present
- When purge valve is stuck open/random idle speed
- When purge valve is stuck closed/leaks may develop in the EVAP system
To diagnose a P1443 DTC code, a technician would:
- Scan for codes in the ECM and look at the freeze frame data for failure.
- Visually inspect the wiring and connectors for damage.
- Test the FTPS sensor for proper function.
- Check the fuel tank pressure sensor for proper function.
- Check the EVAP purge control valve for proper function.
- Check the vacuum lines and hoses for leaks or damage.
- Test the charcoal canister for proper function.
- Check the PCM for errors.
The following are some of the most common mistakes that a technician may make when diagnosing a P1443 code:
- Failing to inspect the wiring and connectors for damage.
- Testing the FTPS sensor without properly disconnecting it from the wiring harness.
- Not checking the fuel tank pressure sensor for proper function.
- Not checking the EVAP purge control valve for proper function.
- Not checking the vacuum lines and hoses for leaks or damage.
- Not testing the charcoal canister for proper function.
- Not checking the PCM for errors.
How serious is this?
A P1443 code is a serious code and should be diagnosed and fixed as soon as possible. When the EVAP system does not have proper flow, it can cause a number of issues such as bad fuel efficiency, strong fuel odors, and illuminated Check Engine Light. If the code is not fixed, it may eventually result in a failed emissions test.
What repairs can fix the code?
The following are solutions that may fix this problem:
- Repair or replace any wiring that is damaged
- Replace the purge control valve
- Repair or replace any faulty circuit in the EVAP purge control valve
- Clean the FTPS sensor and incoming hose or connectors between the purge control valve and FTPS
- Replace the fuel tank pressure sensor
- Replace the charcoal canister
- Repair or replace any vacuum lines or hoses that are damaged or dislodged
- Repair or replace the PCM
A P1443 is related to and may be accompanied by the following codes:
P1444 – Evaporative Emission System Vent Control Circuit Malfunction
P1445 – Evaporative Emission System Leak Detected (Fuel Tank)
P1446 – Evaporative Emission System Vent Valve Control Circuit Malfunction
P1447 – Evaporative Emission System Purge Flow Control Valve Malfunction
In conclusion, the P1443 code is a diagnostic trouble code that refers to a problem with the evaporative emissions system. The code is usually caused by a shorted, open, or damaged circuit, a faulty purge control valve, or a clogged FTPS sensor. The symptoms of the code can include illuminated Check Engine Light, bad fuel efficiency, and strong fuel odors. The code should be diagnosed and fixed as soon as possible to avoid any further issues.