Fault codes p0171, p0174, 01128, p1129

Good morning,

The 1128,1129 codes are for fuel mapping from the PCM. It is not seeing the correct information to control the fuel mapping from the O2 sensors. You may need O2 sensors, but needs to be confirmed. I posted a list of possibilities below that need to be checked by someone with a scan tool.

The 171,174 are for lean condition. It could be from a vacuum leak, low fuel pressure, PCV valve or a mass air flow sensor. Again, all these items need to be checked for the failure. I posted the possibilities below for this as well.

Roy

1128,1129

P1128
Descriptor
Closed Loop Fueling Not Achieved - Bank 1
Probable Causes
Engine Coolant Temperature (ECT) Sensor, Wiring or Connectors
Engine Mechanical System
Fuel Delivery System
Manifold Absolute Pressure (MAP) Sensor, Wiring, or Connectors
Oxygen Sensor (O2S), Wiring, or Connectors
Power-train Control Module (PCM)

171,174

P0171
Descriptor
Fuel System 1/1 Lean
Probable Causes
Engine Coolant Temperature (ECT) Sensor, Wiring or Connectors
Engine Mechanical System
Fuel Delivery System
Manifold Absolute Pressure (MAP) Sensor, Wiring, or Connectors
Oxygen Sensor (O2S), Wiring, or Connectors
Power-train Control Module (PCM)

Thanks, I will check and inform.

You are welcome.

Always glad to help.

Roy

Could you please send locations for all sensors, engine mechanical system and fuel lean system?

O2 sensor locations attached as requested.

Roy

Amigo you are the best. Thanks

Thank you.

Always glad to help.

Roy

Hi,
I checked all lines I found EGR tube sucking air. Is that normal?
And if it is not normal it will make this problem?

Tube? do you mean the line from the exhaust or a vacuum line?

If it is the vacuum line, yes it will.

If it is the exhaust tube, no it will not.

Roy

Vacuum line

The vacuum line should not have vacuum. It is opening the valve and that will create a huge vacuum leak and set the codes.

Can you verify the engine and year? Check the production date on the left door. I only see a linear valve which is electronic not vacuum controlled.

Roy

2009, 3.5L six cylinder.

Can you post a picture of what you are referring to?

I want to make sure it is the EGR valve.

Roy

Yes I am sure it is EGR. There is blue seal there.

Can you post a picture for me to see what you see?

Roy