P1151 Lack of upstream Heated O2 Sensor Switch Sensor Indicates Lean Bank 2

[tedmc1]

P1151 Lack of upstream Heated O2 Sensor Switch Sensor Indicates Lean Bank 2. Just like the header says,I failed my smog test today. Looked at FordParts......the search box returns DY 1401 (9G444) If you look at the diagram it looks like the upstream O2 sensor is actually (9F472) I guess bank 2 is driver side. Can anyone be certain which one I need?
Second question.....Do I need a special tool to r and r?
4.0 SOHC Engine

 

[muddycreek]

P1151 Lack of upstream Heated O2 Sensor Switch Sensor Indicates Lean Bank 2. Just like the header says,I failed my smog test today. Looked at FordParts......the search box returns DY 1401 (9G444) If you look at the diagram it looks like the upstream O2 sensor is actually (9F472) I guess bank 2 is driver side. Can anyone be certain which one I need?
Second question.....Do I need a special tool to r and r?
4.0 SOHC Engine

Bank 1 Drivers Side
Bank 2 Passenger Side

Upstream before CAT
Downstream after CAT

 

[410Fortune]

Allright don't go replacing your HEGO just yet.... (heated exhaust gas oxygen sensor)
The sensor may in fact be doing its job
You likely have a rich condition on the passenger side:

Ford P1151 Lack of HO2S-21 Switch, Sensor Indicates Lean

 

[tedmc1]

Bank 1 Drivers Side
Bank 2 Passenger Side
Why does every diagram show bank 1 as passenger side?

 

[410Fortune]

bank one is whichever cylinder head is furthest forward ALWAYS
so if the head on the passenger side is further forward then the drivers side, that is cyl #1, and that is bank one.
On a 4.0L engine the passenger side head is closer to the fan the n the drivers = pass side is bank 1

See? Cyl #1 is passenger side front, so bank 1 is pass side, all 4.0 V6 are the same

 

[tedmc1]

 

[tedmc1]

Allright don't go replacing your HEGO just yet.... (heated exhaust gas oxygen sensor)
The sensor may in fact be doing its job
You likely have a rich condition on the passenger side:

Ford P1151 Lack of HO2S-21 Switch, Sensor Indicates Lean

Thanks 410..... I've got torque pro and my fuel trims on bank 2 are always a little out of whack when the truck is idling,however when i accelerate (even gently) the trims snap to almost perfect. Numbers like (+1 and -2) offset total of 1 just as close to perfect as can be expected.When I am idling they get a little wacky ..which is why I suspect a vacuum leak. Just need to get a smoker and find the leak.
I've read that the instant the offset total of fuel trims is 10 the truck throws a code. I've gotten the code around 10 times in the past 18 months....It always happens when I'm idling after driving on the freeway and engine is fully warmed up.Bank 1 always shows perfect trims under all driving conditions.
I've never paid any attention to the fuel trim meter other than to notice whether that they were close to zero. I'll have to run it again and try to figure out whether the computer is trying to correct a too rich or too lean condition.
Thank You,Ted
RECENTLY REPLACED Fuel pump and Fuel filter

 

[410Fortune]

I would look at your EGR and Canister vent systems for the leak
Idling after highway for me has always been a canister purge/canister vent issue

The smoke tester might only work when you replicate the situation, idling after highway

If you recently replaced the fuel pump and this code never came up before that job, I would start there.....is the vent line hooked up properly? Is the pressure sensor plugged all the way in? Did any lines get pinched or crimped when the tank was dropped?

 

[tedmc1]

Thx for the reply 410,I cut a hole in the floor and replaced the fuel pump that way. Only needed to disconnect the 2 electrical connectors and the 2 fuel lines.
I was getting the P1151 prior to the Fuel pump and Filter replacement.
Guess I need to look at the EGR and Canister locations and find the hoses.
Got any diagrams showing their locations?
THX ,
Ted

 

[410Fortune]

unfortunately I do not, I have not done much work on Gen III trucks
I am sure somebody here does