05 with SES code 45 and heater problem...

[1wizeguy]

Hey guys, I got an 05 Pathfinder with 40k miles.. When I first started the truck this morning, the Service Engine Soon light came on.. So I did the "push the gas peddle 5 times deal" and it came up with a code 45..
This other problem has been going on for the past couple winters...while I'm sitting at a light with the engine idling, the heat that comes out of the vents cool down... If I raise the rpm's a bit or take off, the vents start blowing hot air again. I checked the antifreeze level and it seems to be perfect.. any suggestions?
Thanks

[Towncivilian]

Code 45 ... huh? I can't find any reference in the factory service manual for such a code. Could you go to AutoZone and have them pull codes and post the DTC here? It'll look something like P0325.

As for the low heat at idle, has the coolant system ever been flushed, or a drain & fill of the radiator done? If so, there may be an air bubble - jack up the front of the vehicle to have the radiator cap as the "highest" point in the system to help burp any air. If there's no air bubbles, the heater core might be clogged. A coolant flush will help in such case. If the vehicle hasn't had a cooling system service done yet, it's overdue as it's supposed to be done after 4 years or 60k miles, then every 2 years thereafter. The service manual says that only a radiator drain & fill is required for standard scheduled maintenance, but in your case a flush may help solve the heat issue. If you get a coolant flush done at a Nissan dealership, ask for the blue long-life coolant - it lasts longer than the green your Pathfinder came with and is safe to use in vehicles specified for Nissan's green coolant.

[1wizeguy]

I took the truck to Autozone and the guy was in a hurry acting like a prick but he mumbled wide open vacuum leak and said "all it might be is tighten your gas cap"... then he walked away.. I'll hit a different Autozone and get the code #..
The Antifreeze was done at the dealer, 7000 miles ago.. I'll give that a check out, doubt if the dealer would do anything about it now.

[boagwood]

Hi, if you're not low on coolant, you probably have a partially clogged heater core. Feel both hoses that go to the core,if both aren't hot its clogged. I'm not positive, but if most cores are similar you should be able to clean it yourself. Use the existing hoses that go to the intake and outlet of the core by putting on bypasses that can connect to a garden hose. pathfinders might have existing connections, I don't recall if i've seen any on mine. Anyway, you must isolate the part you're cleaning, don't let cleaner get into the rest of the heating system. Flush the core with water backwards first, then blow the water out of the core with compressed air or simply lung power. Add CLR(calcium,lime,rust dissolver) maybe half a bottle and let it sit in the core for an hour or so. pump the CLR back and forth through the core a few times( Taurus owners call this fix the Jenna Jamison for obvious reasons) Flush it out multiple times with lots of water and in both directions. It will eventually run clear, and you should get great heat.
hope this helps, but since i'm unsure of the makeup of nissan heater cores, check with a service dept. B4 you do this.

[1wizeguy]

The code was erased and about 300 miles later the SES light came back on..
Hit another Autozone and they found the code P0455.
Any help on this one?

[Towncivilian]

The code description is "DTC P0444, P0445 EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE". See page EC-332 - basically the only cause is the harness or connectors for the solenoid valve, or the solenoid valve itself.

[1wizeguy]

Thanks... looks like I'll tackle the easy/cheapest thing.. Change the gas cap/inspect hoses, harness and connectors.
If the light comes back on, I'll have to bring it to the dealer