RomRaider

I have a spare ECU from a 2008 G35 (VQ35HR) that want to dump the ROM, mostly to learn without fear of bricking my ECU.

If I connect:
(1) 12 volts to pin 53, 125 (battery)
(2) ground to pin 128 (ground)
(3) ISO 9141-2 (from VAG-COM) to pin 117
The VAG-COM will also connect to power.

It is really that simple?
The attached PDF may be helpful to others.

Next time I am at the scrap yard, I will pick up a few OBD connectors and make a proper cable, with CAN support for enhanced diagnostics.

Thanks in advance.

I'm just getting into having to do some bench stuff. I believe the connections you'll require are:

+12V main (constant supply)
+12V ign (key on)
GND
optional ECU GND (it is separate from the main GND)
COMM lines as desired

I can confirm these ECU pin outs for the VQ35HR and VQ37VHR are the same:

Pin - Function
53 - 12v (ignition on)
93 - 12v (backup power)
113 - CAN Low
114 - CAN High
117 - K-Line
125 - 12v (ECU power)
128 - Ground

My VAG-COM cable should be arriving next week.
THEN I will find out if a 3 amp power supply is enough for the HR ECU and if I have read enough to
dump the ECU.

Well... the bench top HR ECU only uses 170ma, so the 3 amp power supply is good

Later today I will be connecting my OBD scanner to retrieve the ECU ID, serial number and just for fun I will run a diagnostic report. It will be interesting to see how many faults the ECU will declare when it isn't on the CAN bus and doesn't have any sensors plugged in.

It depends on power voltage applied.
Start with 6-7V and rise voltage slowly.
You will see rising number of errors.

I don't understand... What is the purpose of applying 6-7 volts and rising the voltage slowly?

The ECU is designed to handle 12-14+ volts and the ECU has an onboard 5V regulator.

If you wanted to know how many trouble codes you will have with the VQ35HR ECU running on your desk the answer is....
23.

The ELM327 scanner didn't connect to the CAN bus, but instead used the K-Line.
I suspect this is due to the CAN bus missing the 120 ohm termination resistors. I will add them and see what happens.

The terminating resistor didn't make any difference and my scan tool can't connect to the ECU on the CAN bus.
K-Line works well.

I checked the quality of the CAN bus signal and it looks good:


My scope was not able to decode every frame, so I built an Arduino based CAN sniffer to capture and display the ID and data of each frame:


As for why my scan tool can't connect to the ECU via the CAN bus, I suspect the ECU is stuck in a
boot up mode where it loops until it finds the critical modules like: transmission, body control, etc.

Later today I will be analyzing what the ECU is sending out.

The trip to the scrap yard was very productive. I picked up a few OBD ports and an ECU (with harness!!) from a 2010 Altima: (4 cylinder QR25DE)


The CAN Bus shield uses the MCP2515 chipset for the CAN bus to SPI conversion.
It took me about 6 hours to figure out how to program the mask/filters to allow specific CAN IDs to pass through.
It is a very unusual bit masking of the CAN ID, allow/disallow bits in the mask and XOR with the filter.

The next step is to send the ECU specific OBD commands (like 01 04 for coolant temp) and see how it responds. When I used an ELM327 scan tool, the ECU didn't respond at all.

Soooooo, the 2007 G35x ECU does CAN communication, but not for OBD diagnostics - that is only done on the K-line.
BUT the 2010 Altima 2.5 ECU had no problems with my scan tool on the CAN bus.

This tells me an 2008+ ECU on the bench doesn't need to see any other modules for the CAN diagnostics to work.
(2008 is when it was required to move OBD diagnostics to the CAN bus)

My VAG-COM cable arrived and I will try dumping both ECUs (7058s) tomorrow. It should be interesting to see what happens.

Heya Frank. Were you able to get this working? I'd like to do similarly with a VQ35DE ECU I pulled from a scrapyard, and get k-line working so I can use Nisprog to dump and flash.

Cheers.

EDIT: Nevermind, got it using the info you posted Here's how I wired it up to the OBD2 connector (see image attached).

Then I was able to read via K-line using Nissan DataScan. Strangely, I was only seeing 6 trouble codes thrown lol. Going to be trying Nisprog tomorrow to see if I can dump ROM.

I'm glad you got it working... I haven't tried to dump the ECU, as I needed to focus on other projects.
BUT I will pick this project up again over the winter.

How did you make out dumping your ECU?

So I got tired of having jumpers and alligator clips all over the place so I bought an OBD2 connector and soldered together a makeshift harness.

I was able to dump the ROM just fine with Nisprog while on bench power! I followed along with this thread here: viewtopic.php?f=64&t=14867

Can you show what settings you used for the CAN filters?