Atmospheric Pressure Sensor on 4.0

Does anyone happen to know where the ECU gets its Atmospheric Pressure Reading from ? Which Sensor ? Where is it located?

 

Here is a list of the PID's for the Truck......Notice the Atmospheric Pressure is 36.9.......That's definitely not the case...Trying to figure this out

 

I'm pretty sure if it's used it's a calculated value and there's no actual sensor.

 

So this all stems from a P0453 Code......Canister Pressure Sensor Voltage High......But the Voltage reading all the way back to the ECU is well within Limits to not throw a code.....Could I possibly have a bad ECU

 

I have only known there to be an air pressure sensor on the 2.7L 2TR-FE, and not on the 1GR. On the 4cyl. it is located on the RH side near the rear of the engine approximately near where the tube from the air box is relative to the the valve cover. Its connector has two wires. Oh, and I remember it being a very expensive sensor.

 

I would suspect a wiring or sensor problem, here's the service info for that code.

 

DM93....Thank You for that info.....When I backprobed the Sensor all the way to the ECU.....The sensor never retuned a voltage that was "Out of Range".....I always had a voltage that was within the "Usable Range" so there is no reason in my eyes why the CEL would come on

 

Cant provide much help as to where exactly it is, but Im pretty sure these engines have one. Somewhere along the intake plenum I would guess, post air filter. I base that on my ScanGaugeII. Normally reads out right around the 100-101 kPa range (somewhere in the range of 29.9 inHg I think)

Going up into the foothills leads to reading out a lower number. And a severely blocked air filter also leads to a much lower number. I wonder if it is integrated into the MAF unit?

 

No problem, so did you find where your problem was?

 

I can't find any info on it but there's no external sensor, it's most likely either integrated into the ECM or a calculated value.

 

The calculated part is what Im worried about and believe that may be why I have an ECU Problem......The voltage of the sensor being retuned to the ECU is within limit but the data being interpreted by the ECU is out of range. The sensor I am referring to that I backprobed is the Pressure Sensor in the Charcoal Canister

 

maybe the sensor is failing intermittently. Does the code come back quickly after clearing?

 

I cant even clear it.....The ECU's interpretation of the data is Out of Range High so it just comes back instantly

 

What voltage are you getting on the signal wire, on a 5v sensor generally a valid range is 0.5v-4.5v.

 

Note that the ATM Pressure reading on the PID is different than the pressure sensor in the canister

 

Per the TS recommendations, replace the charcoal canister.

 

When I backprobed all the way the way to the ECU connector I was getting 2.9v to 3.1v......Well within the usable range

6GearT444E.....Thats some great Info...I appreciate that....The charcoal Canister is Brand New from Toyota....Its all making me lead harder towards the ECU now

 

Based on what 6GearT444E is saying makes even more sense as to why I got all these EVAP codes to begin with. If my atmospheric pressure reading is that far off (which now I know comes directly off the ECU) there is no way for the Canister Pressure and the Atmospheric pressure to be close to one another to Satisfy the Sealed and Vented Status of the EVAP System

 

That’s weird then, it’s likely not the canister usually what happens when they fail is the filter degrades, the purge Valve fails, or fuel gets in from over filling the tank and damages the vacuum pump.