P1131 code

[Bigdame]

I won my mer in auction got in it drove it for a day the check engine light came on I put it on the scanner and this code came up the car seem to be running fine what I want to know is. Is this something I need to worry about and what is it exactly is it just an 02 sensor that need to be replace I just hope it's not major thanks

[BAD MERC]

I don't know what you drive but using 2004 Marauder VIN "V" as a search in Identifix I got this;

However, these only came up as codes for a 4.6 VIN "W" vehicle.

POTENTIAL CAUSES;

Plugged Fuel Filter
Plugged Fuel Injectors
Low Fuel Pressure
Weak Fuel Pump
Poor Fuel Quality
Low Mass Air Flow Sensor Voltage
Leaking Vacuum

CONFIRMED FIXES BY MOST COMMON;

8 - Intake Manifold Gasket(s)
5 - Intake Manifold Assembly
3 - Mass Air Flow (MAF) Sensor
3 - Oxygen (O2) Sensor(s)
2 - Powertrain Control Module (PCM)
1 - Coil On Plug(s) (COP)
1 - Vacuum Hose/Line(s)
1 - Fuel Pump
1 - Air Intake Tube
1 - Cylinder Head(s)
1 - PCV Hose
1 - Intake Manifold Assembly and Intake Manifold Gasket(s)
1 - Intake Manifold Gasket(s) and Valve Cover Gasket(s)

[Bigdame]

It's a 04 and thanks

[fastblackmerc]

Don't know what BAD MERC is referencing............

P1131 Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Lean - Bank 1

Find more info here: https://www.engine-light-help.com/ford-check-engine-light.html

BTW... I'd replace both O2 sensors at the same time and the MM has a total of 4 O2 sensors.

[BAD MERC]

I used Identifix. It's my shop account and that DTC is what gave me that information.

[alec2538]

My car threw the exact same code. Just replace both upstream O2 sensors. Motorcraft OE sensors can be had new for around $45.

When in closed loop, as the PCM changes fueling to maintain the desired air/fuel ratio, there's a pre-programmed window of time within which it expects to see a response from the oxygen sensor on that particular bank. When the sensors get old, it takes them SLIGHTLY longer to react to the change in oxygen content in the exhaust. This slow reaction sets a your code.

Basically, Ford set the parameters for the O2 sensors just a smidge too "tight", so to speak. When I watched my sensors with a scanner, they appeared to be operating perfectly. However, they were just slow enough, on occasion, to upset the PCM.

[Logizyme]

+1 for replacing both upstreams

[2,4shofast]

I had the same code last fall, replaced both upstreams and all was well.

[fastblackmerc]

No codes but I'll be replacing mine after 80+k miles.

[FordNut]

No codes but I'll be replacing mine after 80+k miles.

Still on the factory installed ones at 260k