I'm unable to obtain Short Term and Long Term Fuel Trims from a 2003 (4.2 litre) XK8. I have paid versions of Torque with Bluetooth interface and Dash Command with WiFi interface and can retrieve most of the info.

STFT and LTFT however show as zero%.

I'm wondering whether the PIDs have changed from the 2003 4.2 litre model upgrade?

Can anyone confirm that or advise what the PIDs are?

Thanks in advance

 

No change in PIDs etc.

Can you read other live data such as ECT & IAT?

Can you see codes such as P1000 or P1111?

Can you read the status of the OBD monitors? If so, any unset / which?

 

Thanks JagV8,
I'm not near the car at present but I do know that both Torque and Dash Command display RPM, ECT, IAT, MAF Ignition Timing etc.Fault codes P1646 and P0182 have been there for ever.
I'm trying to read STFT Bank 1 and Bank 2. Also LTFT Bank 1 and Bank 2. Is that the correct banks?

 

I have a 2004 XK8. I could not get the Torque Pro app to work for me but Dash Command works fine. Reads both short and long term fuel trims fine.

 

Thanks Barry,
Can you confirm that you are reading 'Long Term Fuel Trim - Bank1', 'Long Term Fuel Trim - Bank2' etc from the Data Grid view in DashCommand?

 

I can't confirm that right now because the car is stored for winter. Sorry. But I do know that I have observed a number of long and short term fuel trim readings. The ones you quote sound vary familiar.

 

Thanks Barry,
If you have your phone with DashCommand you could start DashCommand and select the DATA GRID view. That shows the active PIDs. Doesn't need to be connected to the car. Might need to scroll down. Mine shows 'Long Term Fuel Trim - Bank 1' etc.
We toured NFLD a few years back. Beautiful area but can understand why you store your XK8 for the winter.

 

Just went through the same.

I can confirm the ECU keeps the fuel system in open loop (let say standard fuel map - no dynamic interaction) if an O2 sensor is broken (P1646 - right hand side upper).
That results in both STFT's and LTFT's reading zero, where my effected O2 sensor sometimes displayed NO DATA.

Replaced the O2 sensor with an original DENSO 234-9029 (your lucky, right hand side, 20 min max), and all went back to normal.

 

With those codes - fix the fault(s)!!

Forget reading trims until you have. How on earth can it set meaningful trims with non-working vital O2 sensor??? It can't.

 

Tried to open Dash Command but it can't connect to the OBD2 reader ( in the glove box of the Jag ) so it won't do any thing. When I open the grid view all I get is one screen with no values and I can't scroll.

 

Never too old to learn. Thanks Eric, Barry and JagV8 for your help. I'll make the 02 sensor a priority. The specialist I use has said that the car is running so well, even though it has 209000 kilometres up, so why fix it now. Just lately though I have suspected (or imagined) there is less power in some situations which is why I went chasing LTFT readings.

 

Good luck, and frankly speaking, I am not sure I should have my car maintained by a guy saying the above ....

If you experience less power, you might have a more complete check on the fuel system, including condition of fuel filter (ever changed?), the code P0182 code, the fuel pressure, and the likes ...
FYI, I did not really notice a difference in power after I replaced the O2 sensor.

 

Thanks Eric,
No, I wasn't expecting that changing the 02 sensor would solve any possible power issue. Being able to read the LTFTs though might provide a check on the MAF etc.

 

A specialist who isn't very knowledgeable apparently! Find an actual specialist if you can...

 

when I first got started in the motorcycle service industry at a Triumph dealership 49 years ago, one of my best mentors counseled me thusly, "...some mechanics learn during their first year, then merely repeat that first year over and over 20 or 30 times. Don't be one of those...." !!!


Z