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Cat was born on 1994, with Facelifted Face and Strong V12 6.0L Heart.
Hey guys, i'm constantly trying to deal with my FF44 Error. I do also feel that as soon as Check Engine light lids on - Right Bank (And the same said in error code) starts working a bit burpy - not so smooth as Left bank.
I have checked Exhaust for leaks - everything is perfect. I have changed new O2 Sensor (NOT Bosch one) - again error came back after 10 min. of driving.
Is it really so that we need to use ONLY and ONLY Bosch O2 Sensors because they are somehow different (I really don't want to believe that they are different).
If yes, maybe someone can help me to track the correct one? I've seen plenty of different types of connections for those.
This error is soooo annoying and i cannot solve it for already couple years.
Thank you in advance for all your help.
What oxygen sensor did you install? The sensors for the 4.0 engined cars use titania sensor, which are different, but there's nothing that would require you to use a Bosch sensor. Denso is probably the OEM manufacturer.
I believe Denso it is.
But FF44 still remains - all other options are checked - additional Ground is there, all other Grounds are cleaned and checked. No Exhaust leaks whatsoever.
And as read in many other Forums this might be caused by NOT using Bosch O2 Sensor.
As I'm sure you know, there is stuff all over the internet relating to Jaguar XJS FF44 codes. Google it and read every thread on every forum. It may give you some other ideas as to where to look, including incorrect throttle butterfly adjustment.and synchronisation.
You could try and establish if it really is something on that side of the engine, by clearing the code then swapping over the sensor plug wires at the loom attachment point. If the fault jumps to an FF45, then you know it is still something on the A-bank side. If it rethrows still as an FF44, then you might start to look at the sensor wiring back to the ecu.
I've used the NTK sensors an they worked just fine and cured my FF44. I like them better than Bosch, as they are a smaller diameter and easier to install.
The V12 uses the common type sensors, there is no reason to only use Bosch.
Whilst I have read (on this forum) of others struggling with non Bosch O2 sensors, you might also want to check your fuses as the O2 sensors share the same fuse as nr2 fuel pump on the 6lt V12. Had this fail on my car and kept getting the FF44 code. The second fuel pump only kicks in when the cars over 2800-3000 rpm so under normal driving/acceleration you wouldn't realise its not working and even then I didn't realise for quite some time as previous owner had removed the engine warning light from the cluster! Wonder why?
Lastly I'm assuming you have installed an O2 sensor with heater element as some vehicles/O2 sensors don't have this function and that again would cause your problem.
It is in the boot on the right hand side near the electric aerial and security module.
As per attached, should be a 10 amp fuse.
If this isn't the problem, then it likely is the O2 sensors. As mentioned previously, I did read a while ago about someone replacing O2's with none Bosch units and the car played up, eventually replacing again with Bosch units and all was well again. If it looks like this might be the route you have to go, Bosch do a none model specific O2 sensor that is considerable cheaper then the Jag version. All you need to do is solder (or use joining blocks) your jag connector to the new sensor and away you go. This is what I did when replacing my O2 sensors.
Both banks should be and need to be running smooth with and with out O2 sensor functions. You need to solve this problem first. If you have a missfire from what what you describe as running a "bit burpy" then the engine is passing unburnt fuel and unconsumed Oxygen so the sensor will not give the readings the ECM expects. The O2 sensor logic wont and cant alter the fuel curve enough to cause a miss. Moreover the ECM doesn't even consider the O2 sensor signals until the engine and sensors are given time to come up to operating temp. Once enough time has passed for warm up the ECM will swing the mixture slightly from lean to rich along with the ignition timing and monitor the O2 sensor for expected changes. If the ECM doesnt see the changes it expects it triggers a fault code. You can actually here the ECM doing that when it presents as a gentle raising and lowering of the idle about 50 rpm or so.
In the past I've had to add a ground to the O2 sensors, They factory ground path is through the exhaust piping and resistance from corrosion in the connections wont provide a clear enough path back to ground as those connections age.
Last edited by icsamerica; Jan 29, 2022 at 12:34 PM.
In the past I've had to add a ground to the O2 sensors, They factory ground path is through the exhaust piping and resistance from corrosion in the connections wont provide a clear enough path back to ground as those connections age.
Interesting. Is that for v12's, or the 6's too? Facelift? I know you are familiar with facelifts, just wondering if I should consider this for my 96. Is this as easy as just splicing into the ground wire and bolting it to a known ground location? I'm overfueling again....according to my LTFT. Both equal. Everything has been replaced...
Interesting. Is that for v12's, or the 6's too? Facelift?
Only V12's. There was a TSB on it. Your 96 6 cylinder used the Titania style sensor and they work differently. Instead of the voltage they produce swinging, the resistance changes. They are also 4 wires, instead of 3, so the heater circuit is 2 wires, and the signal is the other 2 and they go direct the ECU.
Correct 02 Sensor for V12 6.0 1994? - Help :)
