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My 205k mileage STR timeline
1 - occasional gearbox limp mode, restart cleared
2 - gearbox limp mode gets worse
3 - I got the gearbox service done (genuine parts)
4 - gearbox gets worse
5 - car occasionally cuts out
6 - now the car wont crank, PATS light is flashing code 24. P is illuminated on the shifter.
Codes are P0753 (gearbox solenoid A electrical) and lots of CAN bus communication errors.
I have tried the can bus resistance test (pins 6 and 14) and get 60 ohms.
I have tried unplugging modules to see if the error goes away, no luck so far.
I am about to unplug the ECM (waiting for a star T30 security bit) to see what happens with that.
My suspicion is the gearbox TCM has fried, but then it communicated to my iCarsoft 930 so I am not convinced. The ECM does not communicate with my iCarsoft, hence why I am suspicious.
I "hope" you are aware of the leaking sealing sleeve on that 6 speed ZF?
Was that changed? It's almost guaranteed to be leaking and your symptoms point directly to that!
As you getting U codes which are network codes.
What happens is this sleeve leaks and transmission fluid gets into the wire harness. This is where all the network errors come from. Hopefully your TCM (Note ZF calls this the "Mechatronic") is OK but they have been know to fail. You can change this sleeve and it's cheap at around $15 or so but the pan must be removed to swap it out
Who did the service? Have they done ZF 6 speeds before? What fluid was used and did they set the level correctly because that's not a easy task. Was the pan/filter replaced? Any solenoids?
I hope you did not do a flush without changing the pan and filter? I don't do or recommend flushes but shops are all about that! It's easy and they only have to disconnect a hose or two and let er rip! But you need to inspect the transmission (That darn sealing sleeve again!) and clean the magnets. ZF also upgraded the pan bolts to a larger size.
Your in the UK so this supplier might not be of any help but in the US this place only supplies ZF parts and information. The CTSC ZF Parts
Do you have any info on the PATS system? Are there any error codes in the car?
I think you need to hook the car to an SDD system as you might have a "Theft" incident going on?
I also don't find a PATS code 24? Can you read it again to make sure?
See the attached PATS flow chart but I do think you need to scan for other codes to figure out what's going on?
Congratulations on 205K miles on that STR!!
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Last edited by clubairth1; 10-29-2023 at 07:34 AM.
As for all the gearbox questions, it was my local garage that have done ZF 6 speed many times, and I provided a proper ZF service kit to them. Doesn't mean they haven't ballsed something up, but really the gearbox issue is not my main concern as the non-crank issue is the no 1 problem. I have managed to get my iCarsoft to speak to the TCM, which makes me think it can't be completely fried.
I have checked the rear gearbox wiring connector (the round one). Can't see any problem with it - no ATF fluid leaking out.
I just disconnected the ECM to inspect. While disconnected I checked the error codes again, and no change. Is this suspicious, or does the ECM only get energised once PATS has passed?
Anyway the ECM looked clean (I was hoping for water ingress or something).
OK see if you can find anything on PATS code 24 as I could not?
Does the car have any codes?
Maybe that will help?
No fluid will leak out of the sealing sleeve? It wicks up inside the wire harness and is completely invisible until that round connector is removed and the pins inspected.
Has it been replaced?
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It turned out to be a broken wire from Fuse 33 (Engine control module and transmission control module battery supply). Whilst I seem to have TCM power, perhaps the ECM power is down? I assume that would cause PATS and CAN bus errors similar to mine?
The problem is fixing the break in the wire, especially as it is stuck on my drive and I have no lift.
The plug looks good and dry! The other side is the sealing sleeve so I think you have no fluid leaking here.
One of the pins kinda looks pushed in a bit?
This has been reported too but yours does not look like it's back very far so maybe just the angle of the photo?
Sorry about the PATS code 24 as I have looked and looked but can't find anything? Always stops at code 23?
That thread is a possibility but the big red flag is no lights on the PRNDL indicator. Does your shifter light up the gear display?
I might have missed that if it does not?
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Do you know how to do the emergency park release of the shifter? I have attached a TSB that might help? That would allow you to put the car in N to move it or to try starting it again? One other "possible" idea? Are you sure the brake lights are coming on? You can't get out of P unless the car knows the brake pedal is being pushed.
With the key on and your foot on the brake you should be able to move the shifter regardless if the engine is running or not?
I wonder if something mechanical broke inside the shifter?
But with a flashing PATS light I think nothing will happen until we can solve what's bothering PATS?
I wish I could find something on code 24? That is a real puzzle.
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I wish I could find something on code 24? That is a real puzzle.
I poked around the web for “PATS 24” and similar, leaving out Jaguar. Found a few vague hits, but ran out of time to dig deeper.
Might be something out there for Ford vehicles of that era. With any luck, one could extrapolate Ford info for our cars. I’ve noticed Jaguar was quite tight-lipped with details of the security system. Perhaps they were afraid of bad guys using the info for nefarious purposes.
U0100 - Lost communication with engine control unit/powertrain control unit C1D15 - Brake switch state C1D14 - Ignition state B1265 - Cool air servo motor circuit failure B1262 - Defrost servo motor-circuit failure B1242 - Recirculating air flow door actuator - circuit failure U1900 - Can communication bus fault passive anti theft system B2879 - Fuel tank jet pump fault U2523 - Can message timeout from the engine control unit B2141 - Non-volatile memory configuration failure P1582 - Flight recorder data is stored/Electronic throttle monitor data available P1797 - Can transmission control unit to engine control unit malfunction U2523 - Can message timeout from the engine control unit
Have you erased the codes and these all come back and are current codes?
I find the U codes are a lot of times caused by temporary voltage and/or network problems and don't repeat or come back.
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OK that not a good sign.
With so many U codes which are network errors is it possible there is some wire harness damage somewhere?
With so many codes it really does not point to anything in particular which makes it doubly tough!
Did you get the car out of P and into N to see if that would help?
Still looks like the car thinks it's being stolen and has shut down? No communication with the passive anti-theft system is a red flag.
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In a previous message, wiring checks of the CAN bus were mentioned. It appears resistance checks were done pin to pin (Is 60 ohms the correct value through the terminating resistor?), but what about either pin to ground? You could have a wire's insulation rubbed away and contacting ground, yet pin to pin would still show the normal value.
With DTC U0100 present, the wiring loom is most likely the place to start looking for damage such as chewed wires, corrosion, or insulation missing as Karl suggested.
10-29-2023, 02:57 AM
STR No crank: PATS code 24
