Hi over a week ago we replaced the 02 sensor and engine light went out - now back on - P1179 error code - were can i find out what this code actually means & what to fix ?
1996 XJR sc

 

http://www.jagrepair.com/images/Trai...20-%202000.pdf

95 page 110

96 & 97 page 121

You can rotate and magnify the document to read the table easier

P1179 is Adaptive fuel metering trim too rich * POSSIBLE CAUSES NA engine – Incorrect MAFS installed

And then there are others

https://www.jaguarforums.com/forum/x...9-code-174510/ See the post # 3 by Qvhk for the TSB

The MAF should read 1.2 volts DC on the middle wire ( Green / Pink ) at the correct idle speed for both engines .

The MAF sensor is different between SC and normally aspirated engines

The O2 sensor CEL codes are not very likely or reliably flagged or shown

The 2 wire sensor in the previous post is the inlet air temp same as the 2 wire engine coolant temp sensor and both effect the fuel ratio or trim . On the SC engine the IAT sensor is buried after the intercooler , See page 86

Don't change any parts until connectors cleaned and verified O2 sensors are on the correct connectors .

On the 4 sensor setup the engine regulation sensors are the aft and the fwd ones are used for efficiency code 420 and 430 . See top of page 81

 

aft being the 2 downstream sensors? my sin replaced the right one and light was out for a week - looks like replacing the left is in order ?

 

Hi Jaglady96,

In addition to the references Lady P linked to, you can download the Diagnostic Trouble Code Summaries for your car at this link:

Jaguar X300 DTC Summaries 1996/1997

Here's the listing for P1179:





In addition to the MAFS signal fault that Lady P mentioned, your Fuel Pressure Regulator (FPR) or a kink or obstruction in the fuel return line could be causing the fuel pressure at idle to be too high. Other issues that can contribute to rich running include a clogged a clogged air filter or an Engine Coolant Temperature Sensor (ECTS) that is sticking at a Cold reading and causing the Engine Control Module (ECM) to continue to apply cold-start or warm-up fuel enrichment even after the engine is hot.

Since you have a supercharged engine, if you had a MAFS from a normally-aspirated engine installed your engine would run lean, not rich.

To narrow down the suspects, use your scanner to read the Live Data with the engine hot and idling. Record the the Short Term Fuel Trims (STFT), Long Term Fuel Trims (LTFT), MAF reading, engine coolant temperature and oxygen sensor readings. Rev the engine to 1,500rpm for 30 seconds and record the readings again, then repeat at 2,500rpm. Post the readings here and we'll try to help make sense of them.

I don't believe your car has a Schrader valve for testing fuel pressure - for that you would have to find a shop with the equipment necessary to tap into the fuel system.

Cheers,

Don

 

Thank you - waiting for my new code reader to come - last one didnt work . this one better quality i hope