Ford P1131, P1151 Fault Codes 3.0 DOHC – O-2 DiagnosticsJuly 18, 2009 5:33 pm Apprentice Auto Tech, Auto Specialty Tools, Ford Problems, How To Auto Repair
2003 Ford Taurus with a P1131 oxygen sensor fault code 3.0 DOHC
This automotive repair blog covers a couple of common fault codes that sets the SES (Service Engine Soon) or CEL (Check Engine Light) whichever term you prefer to use. The codes are a P1131 or a P1151, the P1131 is related to B1 S1 (Bank 1 Sensor 1) oxygen sensor which is located near the firewall on the 3.0 DOHC Taurus pictured above. The P1151 is related to the bank that is located near the radiator. There are several probable causes of these codes, we’ll cover the possibilities to help in diagnosing this particular problem.
First a little info on Oxygen (O-2) sensors, first they are located in the exhaust system. An upstream O-2 sensor is located before the catalytic (CAT) converter, while a downstream O-2 sensor is located past the CAT. The purpose of Oxygen sensors is to help the engine run as efficiently as it can which in turn helps reduce emissions. The Oxygen sensors send information to the car’s computer, so it can control the fuel air mixture. The Oxygen sensors normally switch from lean to rich continuously based on the Oxygen content in the exhaust. The reading that was measured in the exhaust is sent to the PCM (Power Train Control Module) – the PCM rapidly changes the fuel mix to optimize efficiency. If the PCM sees that a sensor is not switching as it is expected, a fault code is set and the SES comes on to warn the driver that there is a problem. Lack of switching could be caused by a vacuum leak, a faulty fuel injector, or a lazy (or slow) O-2 sensor. If both, P1131 and P1151 trouble codes are set at the same time, the problem will most likely be attributed to a vacuum leak past the MAF (Mass Air Flow) sensor or something else that would likely affect BOTH banks. If the problem is only causing one code or the other, but NOT both, the problem will most likely be something that would affect one bank, like a bad O-2 sensor or a fuel injector; the most common cause of a single code either the P1131 or P1151 in my experience has been a bad Oxygen sensor.
If P0171, P0174 codes or both have been pulled using a scan tool see our related automotive repair blog for more free tips diagnosing lean codes.
Question – I have a Ford Taurus and want to change the Oxygen sensor that is located in the exhaust manifold on the windshield side. Is it possible to change the sensor without removing the plastic intake manifold to gain access?
Answer- I know it seems buried. The O-2 sensor can be changed by using your left hand to reach from the passenger side of the vehicle down and behind the upper intake. Use an Oxygen sensor socket, a small extension and ratchet… it can be done.
Question – I’ve scanned a P1131 in my VW, does this have the same code definition?
Answer – The P1131 and P1151 can have different meanings depending on the vehicle make. I’ve included definitions for these codes for different manufacturers below.
P1131 and P1151 Code Definitions for the Following Vehicle Makes
Audi - Bank 2 Sensor1 Internal Resistance too High
Buick – Heated Oxygen Sensor (HO2S) Circuit Low Variance Bank 1 Sensor 2
Cadillac – Heated Oxygen Sensor (HO2S) Circuit Low Variance Bank 1 Sensor 2
Chevrolet – Heated Oxygen Sensor (HO2S) Circuit Low Variance Bank 1 Sensor 2
Chrysler – Fuel Pressure Regulator Valve
Dodge – Fuel Pressure Regulator Valve
Ford – Lack Of Heated Oxygen Sensor Bank 1 Sensor 1 Switches – Sensor Indicates Lean
GMC – Heated Oxygen Sensor (HO2S) Circuit Low Variance Bank 1 Sensor 2
Jaguar – Lack of Heated Oxygen Sensor Bank 1 Sensor 1 switch, sensor indicates lean
Jeep – Fuel Pressure Regulator Valve
Lincoln – Lack Of Heated Oxygen Sensor Bank 1 Sensor 1 Switches – Sensor Indicates Lean
Mazda – Lack Of Heated Oxygen Sensor Bank 1 Sensor 1 Switches – Sensor Indicates Lean
Mercury – Lack Of Heated Oxygen Sensor Bank 1 Sensor 1 Switches – Sensor Indicates Lean
Oldsmobile – Heated Oxygen Sensor (HO2S) Circuit Low Variance Bank 1 Sensor 2
Pontiac – Heated Oxygen Sensor (HO2S) Circuit Low Variance Bank 1 Sensor 2
Saturn – Heated Oxygen Sensor (HO2S) Circuit Low Variance Bank 1 Sensor 2
Subaru – Oxygen sensor circuit malfunction (Short circuit)
Toyota – Air-Fuel Sensor Circuit Range/Performance
Volkswagen – Bank 2 Sensor1 Internal Resistance too High
Linking: Please reference this auto repair article when quoting, linking to this page is welcomed and appreciated. If you are new to linking a page. 1. Left click the link; to highlight 2. Right click, select copy 3. Right click and paste to forum, blog web page etc. Thanks! Disclaimer: Repair tips are designed for informational purposes only, without warranty of any kind, in no event shall the author of this site be liable for any consequential, incidental or direct damages sustained in the course of using the information in this article.
More information for the specific vehicle being worked on can be accessed on-line. Use the information needed now and log back in for other repair projects at a later date, all for ONE low fee. Visit our car repair questions page for info. on how to access the same information that professional shops tap into for their repairs.