Vacuum cut valve bypass

Possible causes - Missing or loose fuel cap
- Incorrect fuel filler cap used
- Fuel filler cap remains open or fails to close
- Foreign matter caught in fuel filler cap
- EVAP canister or fuel tank leaks
- EVAP system hose leaking
- Fuel tank leaking The P0455 it's a very common code, because the code is set if the gas cap is loose or missing. Start by tighten the gas cap and clearing the code. In most cases the code can be clear by disconnecting the car battery for about 30 minutes.

When is the code detected? EVAP control system has a very large leak such as fuel filler cap fell off, EVAP control system does not operate properly. Possible symptoms - Engine Light ON (or Service Engine Soon Warning Light)
- Possible a noticeable fuel odor caused by the release of fuel vapors P0455 Buick Description This diagnosis detects leaks in the Evaporative Emission System (EVAP) purge line using engine intake manifold vacuum. If pressure does not increase, the Engine Control Module (ECM) will check for leaks in the line between the fuel tank and EVAP canister purge volume control solenoid valve under the following vacuum test condition. The vacuum cut valve bypass valve is opened to clear the line between the fuel tank and the EVAP canister purge volume control solenoid valve. The EVAP canister vent control valve will then be closed to shut the EVAP purge line off. The EVAP canister purge volume control solenoid valve is opened to depressurize the EVAP purge line using intake manifold vacuum. After this depressurization is implemented, the EVAP canister purge volume control solenoid valve will be closed.
if tightening the cap or replacing the cap does not help take your car to a shop to have it diagnosed as it requires special tools/equipment to test this and get an accurate results to find what needs replacing.

• cod 1491

Try replacing gas cap first before you spend any money on more on repairs

The code is for a large leak in the EVAP system such as a loose or missing gas cap. But it could also mean a loose or missing hose to the canister or other leak in the tank.
The computer vents the tank several times an hour while the engine is running, and it checks the system by pressurizing the gas tank. If the tank will not hold pressure the code is set.
You may have to check the top of the tank where the fuel pump gasket is, as well as the vent lines to the front of the car.
A mechanic would perform a smoke test to look for leaks.

If the EVAP canister is OK, and there are no other visual damage to the EVAP system (e.g. loose or broken hoses), replacing the vacuum cut valve bypass valve takes care of the problem.

DTC 1491 (VACUUM CUT VALVE BYPASS VALVE) DIAGNOSIS

SERVICE PROCEDURE

1. Confirm the Vacuum Cut Valve is installed correctly

NOTE :

^ The Vacuum Cut Valve will not work correctly and a DTC will be stored if it is installed upside-down.

^ The Vacuum Cut Valve is a white plastic valve near the fuel tank and EVAP canister.


2. Connect CONSULT-II and turn the ignition key to "N" (do not start the engine).

3. On CONSULT II, select ENGINE - DATA MONITOR - SELECTION FROM MENU - EVAP SYSTEM PRESSURE SENSOR.

4. Note the EVAP System Pressure Sensor Voltage Confirm that it is reading in a normal range for a key ON arid engine OFF condition.

NOTE :For 2001 models and earlier:

^ Voltage in step 4 should be near 3.36 volts.

^ The normal range is between 3.32 - 3.40 volts.


For 2002 models:

^ Some 2002 models use a new type EVAP System Pressure Sensor with different operational characteristics.

^ Refer to the EC section of the appropriate Service Manual to determine which type sensor your vehicle is equipped with.

^ Models that use the new type EVAP System Pressure Sensor will have a voltage reading that varies with changes in the "barometric" pressure (atmospheric air pressure that changes with altitude and/or weather conditions).

^ The usual voltage range obtained in step 4 with the new type EVAP System Pressure Sensor is between 3.8 and 4.2 volts. Because this range will vary with barometric pressure, it is best to compare readings with a known good vehicle.

^ Some 2002 models use the earlier type EVAP System Pressure Sensor (same as used on 2001 and earlier models). The normal range for the earlier type is 3.32 to 3.40 volts and does not vary with barometric pressure.


5. Start the engine. Observe the EVAP System Pressure Sensor voltage.

^ If the value has reduced 0.04 volts or more from the reading obtained in step 4, the EVAP Canister Purge Volume Control Solenoid Valve may be leaking.

^ Refer to the EC section of the appropriate Service Manual for inspection procedures of the EVAP Canister Purge Volume Control Solenoid Valve, DTC P1444.


NOTE :The EVAP Canister Purge Volume Control Solenoid Valve is located in the engine compartment.

6. Perform the DTC Confirmation Procedure for DTC P1491. Refer to the EC section of the appropriate Service Manual for confirmation procedure steps and driving conditions.

7. If the DTC confirmation results are NG, do the following:

a. Refer to the EC section of the appropriate Service Manual to determine if the vehicle is equipped with On-Board Refueling Vapor Recovery (ORVR).

^ If the vehicle has ORVR, go to b.

^ If the vehicle does NOT have ORVR, go to step 8.

b. Place a clamp on the Refueling EVAP Vapor Line near the fuel tank. The Refueling EVAP Vapor Line is the larger hose (see figure 2). Use hose clamp (3M P/N # 08556-1), found in Fuel Injector Cleaning Kit J-45701, or equivalent.

c. Retry DTC Confirmation Procedure

d. If the result is now OK, the Refueling Control Valve may be leaking and should be inspected. Refer to the EC section of the appropriate Service Manual for Refueling Control Valve inspection procedures.

8. If the DTC confirmation is still NG after step 7, or the vehicle is not equipped with ORVR, do the following:

a. Disconnect two (2) lines from the Vacuum Cut Valve. One that goes to the fuel tank and one that goes to the EVAP Canister (see figure 1).

b. Use a hand vacuum pump to check each of the two (2) disconnected hoses for free flow. Make sure they are clear into the fuel tank (vent line) and into the EVAP Canister (see figure 2).


NOTE :

^ Figure 2 includes ORVR system. Refer to the appropriate service manual to determine if your vehicle has ORVR or not.

^ The lines between the Vacuum Cut Valve and Fuel Tank, and between the Vacuum Cut Valve and EVAP Canister may go through a metal line. Make sure the lines are clear between the Vacuum Cut Valve and Fuel Tank, and between the Vacuum Cut Valve and EVAP Canister, including any metal lines.

c. If any blockage is found, determine the cause and repair as necessary. Blockage in either of these lines will cause a DTC.


9. If all of the above checks do not locate the source of the incident, refer to the appropriate Service Manual for further DTC P1491 diagnosis.

NISSAN OBDII DTC

P1105 Manifold Absolute Pressure/Barometric Pressure Switch Solenoid Circuit

P1110 Intake Valve Timing Control Circuit (Bank 1)

P1120 Secondary Throttle Position Sensor Circuit

P1125 Tandem Throttle Position Sensor Circuit

P1132 Intake Valve Timing Control Position Sensor (Bank 1)

P1135 Intake Valve Timing Control Circuit (Bank 2)

P1137 Intake Valve Timing Control Position Sensor (Bank 2)

P1140 Intake Valve Timing Control Position Sensor (Bank 1)

P1145 Intake Valve Timing Control Position Sensor (Bank 2)

P1148 Closed Loop Fault Detected (Bank 1)

P1168 Closed Loop Fault Detected (Bank 2)

P1210 Traction Control System Signal Fault

P1220 Fuel Pump Control Module Fault

P1320 Ignition Control Signal Fault

P1335 Crankshaft Position Sensor Circuit

P1336 Crankshaft Position Sensor circuit

P1400 EGR/EVAP Control Solenoid Circuit

P1401 EGR Temperature Sensor Circuit

P1402 EGR System Fault Detected

P1440 EVAP Canister System Leak Detected

P1441 EVAP Vacuum Cut Valve Bypass Valve Circuit

P1443 EVAP Canister Control Vacuum Switch Circuit

P1444 EVAP Canister Purge Volume Control Valve Circuit

P1445 EVAP Purge Volume Control Valve

P1446 EVAP Canister Vent Valve Circuit

P1447 EVAP Canister Purge Flow/Volume Control Valve Circuit

P1448 EVAP Vent Control Valve Circuit

P1490 EVAP Vent Control Valve/Bypass Valve Circuit

P1491 EVAP Vacuum Cut Valve/Bypass Valve Circuit

P1492 EVAP Canister Purge Control Valve/Solenoid Valve

P1605 Transmission Control Module A/T Diagnosis Communication Line Fault

P1705 Throttle Position Switch Circuit

P1706 Park Neutral Position Switch Circuit

P1760 Overrun Clutch Solenoid Valve Circuit
P1900 Cooling Fan Control Circuit
sorry but your code reader is not reading manufacturers codes ,if an american market vehicle then you should be able to read them but if this is a europeon model then how did you manage to get this code??

P0235....Turbo/Super Charger Boost Sensor 'A' Circuit

this is a generic code if its any help

Accelerator Pedal Position Error.

P2138 - Accelerator Pedal Position Sensor Circuit Range / Performance Problem

Clear the code - if it recurs, change the sensor.


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this code is specifically for the vacuum cut valve bypass valve in the evap system. either the valve is not working, is clogged up or a hose is cut