Hi Guys, broke down and bought a Blue Driver diagnostic tool. Have any of you experienced these codes:
P0101 - Mass or Volume Air Flow Sensor "A" Circuit Range Performance. [Replace Mass Air Flow Sensor?]
P0442 = EVAP System Leak Detected (small leak). [Adjust fuel tank cap or replace it?]
P2135 - Throttle/Pedal Position Sensor/Switch "A"/"B" Voltage Correlation. [Replace Throttle Position Sensor?]

I'm still trying to discover why my wife's STR randomly stops running while driving slow or at highway speeds with no warning. But after 2-3 minutes with engine shut off - it starts right up like nothing happened - and then does it again in 5 minutes or 5 days.

Should I just replace the parts indicated by the errors? Thanks in advance if you have a clue.

 

I would tackle them one at a time. I personally have not dealt with them, but a maf cleaning and possible fuel cap replacement are a good start. Easy to do and then clear codes and drive some. The evap will not cause the stall out and the maf should cause poor performance and possible resticted performance. The tps issue might be the culprit, but hopefully those that have dealt with them will chime in. Could even possibly a wiring issue at the tps

 

the tps is about 15 bucks on ebay. usually sold for the xtype

i think they fail more on the str because they’re right under the wiper insulation. car won’t run without tps signal

 

thanks xalty for the tps info. I was not sure about what effect it has on driveability so i did not guess. Always learning on here. I like it. Now i remember reading about water entry into the tps plug now that you mentioned the location under the cowling and drainage area

 

You could follow the pin pint tests in the official jaguar workshop manual for the error codes you have.
Here is a link:
http://www.jagrepair.com/images/Auto...M-Workshop.pdf

 

+1 on that. Follow the link in the post above.

I'd concentrate on P2135 first. Do a control-F search of the service manual PDF and you will get four hits. Note the manual lists six digit fault codes, but you can work with the four digit code you have. The last two digits provide more detail, but the four digit base is enough to get started. All four of those hits say the same basic thing:

"Check connections, etc, clear the DTCs and retest. If the code resets, replace the APP sensor."

Where it says 'if the code resets', I think it really means if the code returns. Also note it mentions the APP sensor, NOT the TPS sensor as previously suggested in this thread. APP = Accelerator Pedal Position, i.e. the gas pedal assembly. You can change the TPS is you really want, but that's not what is being faulted.

With any luck, a new gas pedal assembly should take care of this problem. Looks like it might also clear up the P0101 fault, because one of the possible causes is a throttle adaption fault, which could be caused by the APP sensor.

The P0442 fault is way down on the list of likely candidates. A problem in the EVAP system is not going to shut down the engine.

 

Have a read here https://www.jaguarforums.com/forum/x...8/p2135-78429/

 

2135 is an APP/TPS mismatch. in practice replacing the TPS gets rid of the problem.

all of the DEW98 cars suffer from the wiper insulation dripping, you can improvise and make it water tight if you really want to. the sc throttle body just happens to be right under it.

https://www.jaguarforums.com/forum/xj-xj6-xj8-xjr-x350-x358-28/p2135-fix%3B-x350-engine-system-fault-209761/

 

As i read thru the link i posted i see there are 2 tracks in the tps so they have to match. Now i understand the code wording

 

Both the TPS and the APP have two individual resistor tracks within them, Track A and Track B.
As you rotate the internal wiper through the range of motion on either the TPS or the APP, track A will be increasing its resistance while track B will decreasing proportionally.
This is a design safety feature for 'fly by wire' systems to provide comparison and protect them from any single track failures or tracking irregularities.
If you have a noisy track with dead spots (usually just of idle position is where the TPS and Accelerator unit will incur the most wear) the ECM may ultimately resort to engine shut down if it cannot resolve the disparity.

 

very nicely expained. Thanks

 

From a jag tech, based on the S-Type car MY:
2003-2005: P2135 = Throttle Position related fault, meaning throttle body
2006-2008: P2135 = Pedal Position Sensor related

 

Wow, that little difference could really trip up a guy! I wonder why they changed the definition in the middle of production like that.

OP, what year is your car? No date in your signature or this post to make sure we're looking at the correct manuals.

 

You can test for dead spots using an old-fashioned analog multimeter. As much as I love my digital Fluke, the old-school needle style is best for catching faults like this. IIRC, a replacement TPS or APP is kinda spendy. Might be nice to confirm a fault with the old one before breaking open the wallet.

Off on a little tangent: From what I understand, only the 2003+ models used the dual track sensors, with the inverse operation so the sum was always a constant if all was good. The early models appear to use triple track sensors. I'd imagine the computer simply compared the three values and voted out one if it didn't agree with the other two.

 

OP has an 05

06 and up uses the PanPAG with a single throttle motor/sensor unit.

 

Thanks jagv8 and xalty for clarifying and pointing to the right direction