Dtc p1151 and p1152

[ViperPliskin]

Rebuilt '99 Explorer 5.0 in a '98 Ranger Supercab. TM headers, 1-inch spacer, true dual Flowmaster exhaust, Henson tune.

I'm getting DTC P1151 AND P1152 at the same time.

P1151 Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Lean - Bank No. 2
P1152 Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Rich - Bank No. 2

I've read the posts but I'm still wondering if there is something specific I can get from the fact that I'm getting both codes at the same time. It doesn't make sense that it is reading lean AND rich from the same bank. I know the likely culprits...MAF dirty, vacuum leak or unmetered air, bad sensor, etc...but everything is brand new and has only about 1000 miles on it and I'm getting good vacuum.

It is possible there is an electrical short in the circuit or an exhaust leak on bank 2. But does the fact that I'm getting simultaneous conflicting codes lead me in any particular direction?

I'm also pulling a persistent P1000, but I'm assuming the presence of the other codes is preventing the HEGO monitor from completing.

Any thoughts?

 

[Dan Whitaker]

Rebuilt '99 Explorer 5.0 in a '98 Ranger Supercab. TM headers, 1-inch spacer, true dual Flowmaster exhaust, Henson tune.

I'm getting DTC P1151 AND P1152 at the same time.

P1151 Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Lean - Bank No. 2
P1152 Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Rich - Bank No. 2

I've read the posts but I'm still wondering if there is something specific I can get from the fact that I'm getting both codes at the same time. It doesn't make sense that it is reading lean AND rich from the same bank. I know the likely culprits...MAF dirty, vacuum leak or unmetered air, bad sensor, etc...but everything is brand new and has only about 1000 miles on it and I'm getting good vacuum.

It is possible there is an electrical short in the circuit or an exhaust leak on bank 2. But does the fact that I'm getting simultaneous conflicting codes lead me in any particular direction?

I'm also pulling a persistent P1000, but I'm assuming the presence of the other codes is preventing the HEGO monitor from completing.

Any thoughts?

The P1000 is because the other codes have not been fixed. If you just clear the codes with out fixing what is causing the problem you will continiue to get the P1000.

 

[ViperPliskin]

I'll try to ask the question a little differently.

The problem:

V8 Explorer CEL indicating both P1151 and P1152. One indicates lack of O2 sensor switching while indicating a lean condition, the other for a rich condition.

What I know:

1. Running rich and lean simultaneously. Not likely. Must be a sensor.

2. Both DTCs indicate a bank 2 anomaly. This would seem to rule out factors affecting both banks (MAF, intake vacuum leak, fuel pressure issues, etc). An exhaust leak on bank 2 is not out of the question, but I can't find one.

3. Datalogging of the O2 voltage indicates sensors working correctly. See image.

4. Datalogging of Bank 2 STFT looks questionable.

 

[Turdle]

Looks like the 02 sensor is not functioning. Could be a pin pushed back in the plug, scorched wire, bad connection at PCM, or just a bad sensor.

Or, it just might be possible you have the front and rear 02 sensors mixed up on bank 2 ?

 

[ViperPliskin]

Thanks.

Switched front and back sensors...now there is something I never thought of. I will double check that. However, based on the datalog (not shown) both front and rear sensors appear to be working correctly.

I don't understand the comment about the o2 sensors not working though. They are represented by the pink and blue lines on the graph, which look good to me. Both average about .45V and range from .2 to .8 or so. The shown scale is hosed because I have the fuel trim highlighted.

Maybe I'm missing something or just need some schooling.

 

[muhl5443]

looking at what u have posted it def. sounds to me like u have a bad o2 sensor in bank 2. from ur pic it looks to be that the front o2 sensor is bad. if the voltage is to high or to low then it is the sensor. look where the voltage is at for bank 1 sensor 1. and see where bank 2 sensor 1 voltage is at it is way higher and outta range suggesting that u have a bad bank 2 sensor 1 oxygen sensor.

 

[muhl5443]

what about your fuel filter? and/or fuel pressure regulator? those could be causing it too.

 

[ViperPliskin]

Thanks

Thanks for the replies. In the image above the o2 sensor voltages look to be switching correctly...note the scale shown on the graph is for fuel trim. If I put the scale to o2 it looks to be switching correctly...somewhere between .10 and .90, averaging around .45. I'm not an expert though, you may be seeing something I'm not.

The fuel trim in the graph is definitely screwed, though.

So far I have checked the EGR system, manifold vacuum is good, o2 sensors with datalog and EMM...both seem okay to me. MAF is good. The DPFE voltage is good when checked manually (EMM) but for some reason does not show up on the datalog...I need to check that circuit.

I have not checked fuel parameters yet, but will this weekend.

Could a faulty or dirty IAC cause this?

 

[ViperPliskin]

Fuel?

Thanks Muhl, I think you are on to something.

KOEO fuel pressure jumps to 60PSI, then slowly loses pressure down to 15PSI, then it holds.

At idle, pressure goes to 65PSI and holds, but turn the key off and the system does not hold pressure. It immediately drops to 15PSI.

OK, so there is a fuel leak. Based on those symptoms anybody have any ideas where to start? Could the fuel filter cause that?