3 replies to this topic

[mikal78]

Engine Light ON!

Used craftsman scan tool and it revealed code P0455 Evaporative Emission system Leak Detected (gross leak/ no flow) came up twice. and code P0449 Evaporative Emission System system vent control circuit Intermittent came up twice.

According to the scan tool and software advice, I should tighten or replace the fuel cap?

[Duelin]

Engine Light ON!

Used craftsman scan tool and it revealed code P0455 Evaporative Emission system Leak Detected (gross leak/ no flow) came up twice. and code P0449 Evaporative Emission System system vent control circuit Intermittent came up twice.

According to the scan tool and software advice, I should tighten or replace the fuel cap?

P0449 Gm Definition

EVAP vent solenoid control circuit
– The ECM detects the voltage on the EVAP canister vent valve control circuit is between 2.6-4.6 volts when the driver is commanded off,for more than 4 seconds

Probable Cause[s]

1. Open or short circuit condition
2. Poor electrical connection
3. EVAP canister vent valve
4. ECM fault



P0449 Generic Definition

EVAP (Evaporative Emission System) purge/vent solenoid circuit condition
– The solenoids and system wiring are monitored for opens or shorts

Probable Cause[s]

1. Purge or Vent Solenoids defective
2. Check connector and wiring
3. Fuel saturated vapor canister
4. Failed EVAP Vent Solenoid



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P0455 GM Definition

EVAP system large leak detected
– The ECM detects the EVAP system is not able to achieve or maintain vacuum during the diagnostic test , for more than 4 seconds

Probable Cause[s]

1. Pinched or obstructed EVAP vapor pipe
2. Fuel tank pressure sensor ,EVAP purge solenoid
3. Restriction in the EVAP purge pipe , EVAP canister



P0455 Generic Definition

EVAP Large Leak Detected
– The ECM has detected a large leak in the EVAP system during a system monitor test

Probable Cause[s]

1. Defective, loose or missing fuel cap
2. EVAP canister broke, hose cracked or not connected
3. Purge or vent solenoid defective
4. Vacuum leak at engine

[mikal78]

Engine Light ON!

Used craftsman scan tool and it revealed code P0455 Evaporative Emission system Leak Detected (gross leak/ no flow) came up twice. and code P0449 Evaporative Emission System system vent control circuit Intermittent came up twice.

According to the scan tool and software advice, I should tighten or replace the fuel cap?

P0449 Gm Definition

EVAP vent solenoid control circuit
– The ECM detects the voltage on the EVAP canister vent valve control circuit is between 2.6-4.6 volts when the driver is commanded off,for more than 4 seconds

Probable Cause[s]

1. Open or short circuit condition
2. Poor electrical connection
3. EVAP canister vent valve
4. ECM fault



P0449 Generic Definition

EVAP (Evaporative Emission System) purge/vent solenoid circuit condition
– The solenoids and system wiring are monitored for opens or shorts

Probable Cause[s]

1. Purge or Vent Solenoids defective
2. Check connector and wiring
3. Fuel saturated vapor canister
4. Failed EVAP Vent Solenoid



********************************************************************************

P0455 GM Definition

EVAP system large leak detected
– The ECM detects the EVAP system is not able to achieve or maintain vacuum during the diagnostic test , for more than 4 seconds

Probable Cause[s]

1. Pinched or obstructed EVAP vapor pipe
2. Fuel tank pressure sensor ,EVAP purge solenoid
3. Restriction in the EVAP purge pipe , EVAP canister



P0455 Generic Definition

EVAP Large Leak Detected
– The ECM has detected a large leak in the EVAP system during a system monitor test

Probable Cause[s]

1. Defective, loose or missing fuel cap
2. EVAP canister broke, hose cracked or not connected
3. Purge or vent solenoid defective
4. Vacuum leak at engine

DTC code P0455 corrected with replacing the fuel cap.
DTC code P0449 still Intermittent, but clears with scan tool.

Wondering if I should replace the Vent Solenoid?

[mikal78]

Check Engine Light "ON"

Used Scan Tool and DTC P0449 appeared on the screen Twice Evap Emissions Circuit Intermittent.
Checked the connector and wiring, no loose connector or any damage to the wiring.


Where would I look for a wiring diagram on the Evap Emissions Vent Solenoid Intermittent circuit P0449. Also should I replace the soleniod or the fuse for the circuit?

Engine Light ON!

Used craftsman scan tool and it revealed code P0455 Evaporative Emission system Leak Detected (gross leak/ no flow) came up twice. and code P0449 Evaporative Emission System system vent control circuit Intermittent came up twice.

According to the scan tool and software advice, I should tighten or replace the fuel cap?

P0449 Gm Definition

EVAP vent solenoid control circuit
– The ECM detects the voltage on the EVAP canister vent valve control circuit is between 2.6-4.6 volts when the driver is commanded off,for more than 4 seconds

Probable Cause[s]

1. Open or short circuit condition
2. Poor electrical connection
3. EVAP canister vent valve
4. ECM fault



P0449 Generic Definition

EVAP (Evaporative Emission System) purge/vent solenoid circuit condition
– The solenoids and system wiring are monitored for opens or shorts

Probable Cause[s]

1. Purge or Vent Solenoids defective
2. Check connector and wiring
3. Fuel saturated vapor canister
4. Failed EVAP Vent Solenoid



********************************************************************************

P0455 GM Definition

EVAP system large leak detected
– The ECM detects the EVAP system is not able to achieve or maintain vacuum during the diagnostic test , for more than 4 seconds

Probable Cause[s]

1. Pinched or obstructed EVAP vapor pipe
2. Fuel tank pressure sensor ,EVAP purge solenoid
3. Restriction in the EVAP purge pipe , EVAP canister



P0455 Generic Definition

EVAP Large Leak Detected
– The ECM has detected a large leak in the EVAP system during a system monitor test

Probable Cause[s]

1. Defective, loose or missing fuel cap
2. EVAP canister broke, hose cracked or not connected
3. Purge or vent solenoid defective
4. Vacuum leak at engine