Postby smj999smj » Mon Jan 06, 2020 11:40 pm
P0456 is a code for an evaporative emission system gross leak. Have fuel difficulty issues is usually the sign of a stuck shut evap canister vent control valve (which, if it sometimes sticks in the open position, could cause the P0456 code). So, the evidence points to a faulty vent control valve. The canister is located behind the left, rear wheel well. If you pull the left-rear wheel, there is a plastic panel that needs to be removed to access the evap canister. The canister is held up to a bracket by a 12MM head bolt that is accessible from under the vehicle. You'll have to lower the canister to get at the vent control valve, which can sometimes be stubborn to pull out of the canister. The early valves were black plastic, which were later updated with a more powerful actuator for better sealing capabilities. The newer valve is Nissan # 14935-JF00B, but the part number has been superceded about a dozen times or more. If it has stuck open, it can allow dirt or dust to get into the canister, which can also trigger evap codes, usually P0458. You can weigh the canister to tell if it's loaded up with dirt or not; I'm not 100% sure of the correct weight of the bare canister, but I "think" it was 4.4 lbs. There was also a notice sent out to some R51 owners notifying them of issues of a vent tube in the evap system that could clog and cause similar issues; I forget if it was an extended warranty or an actual recall, but the dealer would have to diagnose the issue and confirm it's the tube before it can be determined if the repair is covered.