jtec pcm read/write eeprom #11

loethansel · 2023-03-06T07:50:58Z

loethansel
Mar 6, 2023

dear mr laszlo,

first, thank you for your lots of work on this tool.

i bougth it to bring an old cherokee xj back on the road. the original jtec-pcm (P56041) was damaged, but i could rescue the data of the 68hc11ka04-eeprom. now i have a donor pcm.

i can connect via sci-bus an read diagnostig data of pcm, but the "read/write_memory"-form doesn't work (no read_write of VIN/mileage/skim is possible).

in further i had also no success with the bootstrap tools. it is possible to load the jtec_bootloader, but e.g. the worker for reading the partnumer or the flash_id comes with no success. loading eatx3_128 bootloader plus the worker for read flash_id i can read the correct flash_id, but the ohter worker don't perform.

please may you help on reading/writing the 68hc11ka04-eeprom of a jtec pcm?

thank you foreward and best regards.
ralf pandel

laszlodaniel · 2023-03-06T08:06:16Z

laszlodaniel
Mar 6, 2023
Maintainer

Hello Ralf, thank you for your feedback!
I'm just in the process to figure out these JTEC behaviors.
We established that the current JTEC bootloader is not appropriate for old units.
They deal with 68HC16 microcontroller and 256k flash chip size.
Need alternative bootloader for "JTEC 128k" and "JTEC 128k+128k" configuration.

I'm asking for your patience while these things unfold this week.

0 replies

loethansel · 2023-03-06T09:03:11Z

loethansel
Mar 6, 2023
Author

Hello Daniel,

I attached a photo of the old pcm, perhaps it helps.

best regards
ralf

eeload.pdf

2 replies

laszlodaniel Mar 6, 2023
Maintainer

As far as I know the 68HC11 MCU you desoldered, which contains EEPROM, can only be reached via the main MCU (68HC16). In this diagnostic framework at least.

Bootstrap mode currently does not support JTEC EEPROM read/write, so your only course of action is to use the "Tools / Read/Write memory" menu, in normal startup mode. The BAK and RES buttons are there to read/write the whole 512 bytes in one go.

Do you have SCI-bus logs before you took out the EEPROM?
Please copy paste it here in a code-block here (``` code ```) that shows when you request diagnostic data successfully, but fails to read/write mileage, SKIM status and VIN.

I must point out, that the EEPROM layout extracted via normal mode and bootstrap mode is slightly different, but content is the same (example: VIN is at a different physical location). For compatibility reasons JTEC EEPROM features are kept in normal mode.

We had the same roller-coaster with SBEC3 and EATX3 bootloaders, thought to be the same but turned out to be different.

loethansel Mar 6, 2023
Author

thank you, I take the log of the sci-bus from donor pcm with "Tools / Read/Write memory" menu at the evening.
Sorry for the delay, I am not at home yet ...

best regards
Ralf

loethansel · 2023-03-06T16:53:56Z

loethansel
Mar 6, 2023
Author

Hello Daniel,

now I can read mileage/vin/skim/partnr, but i can't write it back. I can "BAK" the eeprom, but i can't write ist back.

best regards
Ralf

Here is the code from reading and writing the mileage:

[INFO] -------------Device status--------------
       Timestamp: 00:00:28.865
       RAM usage: 27,2% (145028/532480 bytes)
       Battery voltage: 12.113 V
       Bootstrap voltage: 12.710 V
       Programming voltage: 21.239 V
       -------------CCD-bus status-------------
       State: disabled
       Logic: non-inverted
       Termination and bias: enabled
       Speed: 7812.5 baud
       Messages received: 0
       Messages sent: 0
       -------------PCI-bus status-------------
       State: disabled
       Logic: active-high
       Speed: 10416 baud
       Messages received: 0
       Messages sent: 0
       -------------SCI-bus status-------------
       Module: PCM (Engine)
       State: enabled
       Logic: non-inverted
       NGC mode: enabled
       OBD config.: A
       Speed: 7812.5 baud
       Messages received: 0
       Messages sent: 0
       ---------------LED status---------------
       Heartbeat state: enabled
       Heartbeat interval: 5000 ms
       Blink duration: 50 ms

[<-TX] Send an SCI-bus (PCM) message once:
3D 00 05 26 02 28 00 00 92

[RX->] SCI-bus (PCM) low-speed message:
3D 00 0A A7 01 00 00 C9 78 28 00 00 67 BF

[<-TX] Send an SCI-bus (PCM) message once:
3D 00 05 26 02 28 00 01 93

[RX->] SCI-bus (PCM) low-speed message:
3D 00 0A A7 01 00 00 CA 9D 28 00 01 B5 34

[<-TX] Send an SCI-bus (PCM) message once:
3D 00 03 26 02 2B 93

[RX->] SCI-bus (PCM) low-speed message:
3D 00 0A A7 01 00 00 EB 72 2B 76 8A 2B A2

[<-TX] Send a SCI-bus (PCM) message once:
3D 00 06 26 02 2C 6A 40 D6 17

[RX->] SCI-bus (PCM) low-speed message:
3D 00 0B A7 01 00 00 EB CF 2C 6A 40 D6 00 56

[<-TX] Send an SCI-bus (PCM) message once:
3D 00 06 26 02 27 00 00 0D 9F

[RX->] SCI-bus (PCM) low-speed message:
3D 00 0A A7 01 00 00 EC 5A 27 00 00 0D 69

[RX->] SCI-bus (PCM) low-speed message:
3D 00 07 A7 01 00 00 EC D7 E2 91

[<-TX] Send an SCI-bus (PCM) message once:
3D 00 06 26 02 27 00 00 0D 9F

[RX->] SCI-bus (PCM) low-speed message:
3D 00 0A A7 01 00 00 F4 56 27 00 00 0D 6D

[RX->] SCI-bus (PCM) low-speed message:
3D 00 07 A7 01 00 00 F4 AC E2 6E

[<-TX] Send an SCI-bus (PCM) message once:
3D 00 06 26 02 27 00 00 0D 9F

[RX->] SCI-bus (PCM) low-speed message:
3D 00 0A A7 01 00 00 FC 54 27 00 00 0D 73

[RX->] SCI-bus (PCM) low-speed message:
3D 00 07 A7 01 00 00 FC A2 E2 6C

[<-TX] Send an SCI-bus (PCM) message once:
3D 00 06 26 02 27 00 00 0D 9F

[RX->] SCI-bus (PCM) low-speed message:
3D 00 0A A7 01 00 01 04 5A 27 00 00 0D 82

[RX->] SCI-bus (PCM) low-speed message:
3D 00 07 A7 01 00 01 04 BB E2 8E

[<-TX] Send an SCI-bus (PCM) message once:
3D 00 06 26 02 27 00 00 0D 9F

[RX->] SCI-bus (PCM) low-speed message:
3D 00 0A A7 01 00 01 0C 57 27 00 00 0D 87

[RX->] SCI-bus (PCM) low-speed message:
3D 00 07 A7 01 00 01 0C B2 E2 8D

[<-TX] Send an SCI-bus (PCM) message once:
3D 00 06 26 02 27 00 00 0D 9F

[RX->] SCI-bus (PCM) low-speed message:
3D 00 0A A7 01 00 01 14 56 27 00 00 0D 8E

[RX->] SCI-bus (PCM) low-speed message:
3D 00 07 A7 01 00 01 14 A9 E2 8C

[<-TX] Send an SCI-bus (PCM) message once:
3D 00 06 26 02 27 00 00 0D 9F

[RX->] SCI-bus (PCM) low-speed message:
3D 00 0A A7 01 00 01 1C 57 27 00 00 0D 97

[RX->] SCI-bus (PCM) low-speed message:
3D 00 07 A7 01 00 01 1C AB E2 96

[<-TX] Send an SCI-bus (PCM) message once:
3D 00 06 26 02 27 00 00 0D 9F

[RX->] SCI-bus (PCM) low-speed message:
3D 00 0A A7 01 00 01 24 55 27 00 00 0D 9D

[RX->] SCI-bus (PCM) low-speed message:
3D 00 07 A7 01 00 01 24 B8 E2 AB

[<-TX] Send an SCI-bus (PCM) message once:
3D 00 06 26 02 27 00 00 0D 9F

[RX->] SCI-bus (PCM) low-speed message:
3D 00 0A A7 01 00 01 2C 59 27 00 00 0D A9

[RX->] SCI-bus (PCM) low-speed message:
3D 00 07 A7 01 00 01 2C BA E2 B5

[<-TX] Send an SCI-bus (PCM) message once:
3D 00 06 26 02 27 00 00 0D 9F

[RX->] SCI-bus (PCM) low-speed message:
3D 00 0A A7 01 00 01 34 5B 27 00 00 0D B3

[RX->] SCI-bus (PCM) low-speed message:
3D 00 07 A7 01 00 01 34 B1 E2 B4

This is the message of status-output of "Memory Read/Write":

Before modifying memory content, make sure to backup first with the "BAK" button.

Cycle ignition key for changes in EEPROM to take effect. RAM changes are immediate.

Read SRI Mileage. Done.
SRI Mileage: 350015.3 km

Check PCM status: locked.
Attempting to unlock PCM.
PCM unlocked.

Write SRI Mileage. Cancelled.
Memory write timeout (RX).

19 replies

loethansel Mar 7, 2023
Author

o.k., but difference is 33700km. i do it manually, no problem.
Do i have to remove the skim module or does the pcm learn the code and the system could be untouched?

laszlodaniel Mar 7, 2023
Maintainer

Sorry but I don't understand. Could you walk me through step-by-step what you are doing with the mileage (with logs) and what you would expect?

It depends on how strict the JTEC firmware is regarding SKIM presence. It's best to disconnect SKIM connector after programming FF to EEPROM 0008.
Early JTEC firmwares seem to tolerate this, but newer ones require flash reprogramming to get rid of SKIM completely.

loethansel Mar 8, 2023
Author

i write a 13.2 to the mileage km box and push the write button, this should be converted to 0001 0002 into the eeprom.
but the manually readout is 000A 000B. After pushing the write button, the value in the mileagebox changed to 131.8 automatically.

perhaps this cause the problem: SRIMileageMi = SRIMileageNewRaw * 8.192D;
try to change change to : SRIMileageMi = (double)SRIMileageNewRaw * 8.192D;

here is the code from session above:

[<-TX] Send an SCI-bus (PCM) message once:
3D 00 06 26 02 27 00 00 00 92

[RX->] SCI-bus (PCM) low-speed message:
3D 00 0B A7 01 00 0F 77 A6 27 00 00 00 E2 25

[RX->] SCI-bus (PCM) low-speed message:
3D 00 0B A7 01 00 0F 77 A6 27 00 00 00 E2 25

[<-TX] Send an SCI-bus (PCM) message once:
3D 00 06 26 02 27 00 01 0A 9D

[RX->] SCI-bus (PCM) low-speed message:
3D 00 0B A7 01 00 0F 78 59 27 00 01 0A E2 E4

[RX->] SCI-bus (PCM) low-speed message:
3D 00 0B A7 01 00 0F 78 59 27 00 01 0A E2 E4

[<-TX] Send an SCI-bus (PCM) message once:
3D 00 06 26 02 27 00 02 00 94

[RX->] SCI-bus (PCM) low-speed message:
3D 00 0B A7 01 00 0F 79 0D 27 00 02 00 E2 90

[RX->] SCI-bus (PCM) low-speed message:
3D 00 0B A7 01 00 0F 79 0D 27 00 02 00 E2 90

[<-TX] Send an SCI-bus (PCM) message once:
3D 00 06 26 02 27 00 03 0B A0

[RX->] SCI-bus (PCM) low-speed message:
3D 00 0B A7 01 00 0F 79 B6 27 00 03 0B E2 45

[RX->] SCI-bus (PCM) low-speed message:
3D 00 0B A7 01 00 0F 79 B6 27 00 03 0B E2 45

[<-TX] Send an SCI-bus (PCM) message once:
3D 00 06 26 02 27 00 04 FF 95

[RX->] SCI-bus (PCM) low-speed message:
3D 00 0B A7 01 00 0F 7A 6B 27 00 04 FF E2 F0

[RX->] SCI-bus (PCM) low-speed message:
3D 00 0B A7 01 00 0F 7A 6B 27 00 04 FF E2 F0

[<-TX] Send an SCI-bus (PCM) message once:
3D 00 06 26 02 27 00 05 FF 96

[RX->] SCI-bus (PCM) low-speed message:
3D 00 0B A7 01 00 0F 7B 1F 27 00 05 FF E2 A6

[RX->] SCI-bus (PCM) low-speed message:
3D 00 0B A7 01 00 0F 7B 1F 27 00 05 FF E2 A6

[<-TX] Send an SCI-bus (PCM) message once:
3D 00 06 26 02 27 00 06 FF 97

[RX->] SCI-bus (PCM) low-speed message:
3D 00 0B A7 01 00 0F 7B DE 27 00 06 FF E2 66

[RX->] SCI-bus (PCM) low-speed message:
3D 00 0B A7 01 00 0F 7B DE 27 00 06 FF E2 66

[<-TX] Send an SCI-bus (PCM) message once:
3D 00 06 26 02 27 00 07 FF 98

[RX->] SCI-bus (PCM) low-speed message:
3D 00 0B A7 01 00 0F 7C A9 27 00 07 FF E2 33

[RX->] SCI-bus (PCM) low-speed message:
3D 00 0B A7 01 00 0F 7C A9 27 00 07 FF E2 33

laszlodaniel Mar 8, 2023
Maintainer

Visual Studio says that the (double) cast is redundant there. If you multiply an integer with a double, the result automatically becomes a double type.

From the log it's apparent that the GUI makes the mistake when converting textbox content to a number.

What happens if you write integer mileage only? No decimal point. Perhaps a localization issue is at work.

There are new GUI and scanner firmware updates available!
They include increased SCI timeout and an improved JTEC bootloader (128k+128k).

loethansel Mar 8, 2023
Author

You are right.
If I write a 14 it turns automatically to 13.2 and the manual readout of eeprom is 0001 0002, result o.k.
After that i wrote 380000 it turned automatically to 379995.1 and the manual readout of eeprom is 7097 7098, result o.k.

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jtec pcm read/write eeprom #11

loethansel Mar 6, 2023

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