HomeTrouble CodesP1443

P1443 — Evaporative Emission Control System Control Valve

Manufacturer-specificPowertrain (engine & transmission)

P1443 is a diagnostic trouble code indicating a fault in the evaporative emission (EVAP) control system, specifically with a control valve such as the purge valve, vent valve, or canister close valve. The powertrain control module (PCM) has detected an electrical or functional problem in this valve or its circuit, and the EVAP system can no longer properly route or seal fuel vapors between the fuel tank and the engine intake.

Symptoms

What causes it — most likely first

1. Failed EVAP purge or vent solenoid valve

The valve itself is the most common cause. Internal solenoid coil failure or mechanical sticking prevents proper vapor flow control.

2. Damaged, cracked, or disconnected EVAP hoses

Rubber hoses between the canister, valves, throttle body, and fuel tank can develop splits, loose clamps, or disconnections over time.

3. Wiring or connector faults in the valve circuit

Corroded pins, broken wires, or chafed insulation between the valve and the PCM can produce the same fault code.

4. Saturated or damaged charcoal canister

Less common, but a fuel-saturated or physically cracked canister can prevent the EVAP system from functioning correctly.

5. Loose, damaged, or worn fuel filler cap or seal

A leaking fuel cap can affect EVAP system pressure and trigger related codes, though it more often sets a different P-code.

6. Faulty powertrain control module (PCM)

Genuine PCM failure is rare for this code. It should only be considered after the valve, hoses, wiring, and canister have all been ruled out by testing.

How it's diagnosed

  1. Retrieve all stored codes and freeze-frame data with a scan tool, and note the conditions present when the code set.
  2. Visually inspect the EVAP hoses, connectors, and fuel filler cap for damage, looseness, or contamination.
  3. Measure the resistance of the suspect valve's solenoid coil and compare it to the manufacturer's specification.
  4. Command the valve open and closed with a bidirectional scan tool while listening for the click and watching live data.
  5. Backprobe the valve's power, ground, and signal circuits to confirm proper voltage with the key on and during command.
  6. Perform an EVAP smoke or pressure test to locate any leak the valve circuit may have allowed to set the code.

Code facts & related codes

SystemPowertrain (engine & transmission)
StandardizationManufacturer-specific (P1/B1/C1/U1)

Frequently asked

Is it safe to keep driving with a P1443 code?

Yes, in most cases the vehicle remains safe to drive. The code is emissions-related and typically does not affect engine performance, safety, or immediate drivability.

Is replacing the PCM the right fix for P1443?

Almost never. The code is triggered by an input from the valve circuit, and in the vast majority of cases the actual valve, hoses, or wiring are at fault. Replacing the PCM without first testing those other components is one of the most common and expensive mistakes made for this code.

Will P1443 go away on its own?

It can clear if the underlying condition was temporary, such as a fuel cap that was not fully tightened. Once the EVAP monitor runs again, however, the code typically returns until the actual fault is repaired.

How is P1443 different from other EVAP codes like P0440, P0442, or P0455?

P0440, P0442, and P0455 generally indicate a leak or pressure issue in the EVAP system as a whole, while P1443 specifically points to a problem with the control valve or its circuit rather than a leak elsewhere in the system.