Code P0451

Need help I have a 2004 xcab v-6 and its throwing code P0451 EVAP pressure.Has anyone has this and what could be causing it .I read it could be a pressure switch.

Also I recently replaced the vacume lines that go from canister to hard line under the bed .I used fuel line hose due to no available vacume hose that has a slightly smaller inside diameter do you think that could cause the problem.

 

Been fighting mine for a while. EVAP system leak - small , is what the actual code says. Checked the purge valves on the drs. side inner fender - they are functioning. Can't find any leak. There is a schrader valve to connect a smoke machine but I don't have one of those. Been toying with the idea of using a bicycle tire pump to pressurize the system then squirt soapy water on the connections, but I need a helper. I just reset (shut off with code reader) and it stays off till I get a new inspection sticker.

 

https://www.tacomaworld.com/threads/evaporative-pressure-sensor-needed.335705/#post-17065394

 

I got a po442 code the other day which mentioned a evap (small leak). I seen on here the top of the gas tank where the sending unit mounts can rot away. Meaning, you need a new tank. I haven't looked at mine yet but, if you see wetness around there, good sign that is the issue.

 

From everything I can find on the web the p0451 for a 2004 tacoma means ( Evaporative Emission Control System Pressure Sensor Range/Performance) and the reason for the code is a bad sensor. Whats confusing is I cant find anything that tells you, or shows you where this sensor is.I read allot of posts and web pages they are conflicting some seem to say its on the gas tank others say its on the charcoal canister.Does anyone know exactly where this sensor is ,and a fix for this code or part number for this sensor.Thank this is driving me crazy.

 

It is located under the hood, drivers side above the brake booster attached to a black bracket that is bolted to the firewall.

 

I think they moved it starting in 2002 not there on my 04

 

Has anybody ever figured out this PO451 code. It's driving me insane. I've changed evap canister and all new vacuum lines..appreciate any insight if anybody figured this out!

 

Since you replaced vac lines and canister, I'd double check everything just to rule out any connection issue. Also included Vapor Pressure Sensor location/info. Think you were looking for that as well.

Welcome to Tacoma World! Good luck.

 

Thanks alot but why is everybody else saying it's under the hood (vapor pressure sensor) is 2003 the only one that's on the gas tank? I'm not looking forward to that again. My eva0 canister I removed the can to install... On this thread also it's mentioned the sensor can't be located it's not carried by dealership anymore. Insight please.

 

I just changed my sensor this weekend (p0450) to start you can get the sensor from rock auto https://www.rockauto.com/en/catalog...084,fuel+&+air,fuel+tank+pressure+sensor,6385

To install I took out all the bed bolts put a piece of 2x4 on top a 4x4 between the frame and bed on drivers side right were the middle bed bolt would mount.Next if you carefully feel the side or the sensor you can feel the clip that hold the sensor lock in. If you get a flat head or a pick and pry between the sensor and clip it will pop out allowing you to pull up on the sensor to remove (also must unplug wiring harness) I added a diagram hope it helps