# Gen 2 manual dpf regen



## Chederchad (Aug 14, 2021)

I don't know if @Snipesy would be able to help.


----------



## Snipesy (Dec 7, 2015)

Gretio gives the actual error reason.

This one says “MIL Present”

In Gretio you will have to eitheir do the Tamper Service Bay Test or the “Warning Service Bay Test” for SCR issues. Those aren’t found in BiScan. If you don’t have the subscription you can get that here








BiScan Account Migration


Visit the post for more.




surrealdev.com





Also this may be useful








Emissions Supplemental Repair Guide


Surreal Development’s General Motors Emissions Diagnostic Guide This document is intended to be supplementary guidance based on Surreal Development’s own knowledge of GM diesel engines. This document is made to be a reference in tandem with OEM service manuals and is not made to be a replacemen...




docs.google.com


----------



## Chederchad (Aug 14, 2021)

Thanks I'll check those out I bought both subs today


----------



## Chederchad (Aug 14, 2021)

Snipesy said:


> Gretio gives the actual error reason.
> 
> This one says “MIL Present”
> 
> ...


Sorry newbie. Tried running both of those neither worked got service Regen to start but numbers don't seem right


----------



## Snipesy (Dec 7, 2015)

Chederchad said:


> Sorry newbie. Tried running both of those neither worked got service Regen to start but numbers don't seem right
> View attachment 297710


What DTCs are there?

Dont worry about EGT 4 and 5. It’s because the Cruze is a mini LWN so it thinks it has a dedicated injector.


----------



## Chederchad (Aug 14, 2021)

Chederchad said:


> Sorry newbie. Tried running both of those neither worked got service Regen to start but numbers don't seem right
> View attachment 297710





Snipesy said:


> What DTCs are there?
> 
> Dont worry about EGT 4 and 5. It’s because the Cruze is a mini LWN so it thinks it has a dedicated injector.


The dtcs are u18a2 U02A3 u028e and d 
I I'm trying to try everything before crawling under and checking the wiring because I had a similar issue a year ago with losing power to the nox sensors but it seemed to be a wiring issue with the previous owner overflowing the def and corroding the wires.


----------



## Snipesy (Dec 7, 2015)

Chederchad said:


> The dtcs are u18a2 U02A3 u028e and d
> I I'm trying to try everything before crawling under and checking the wiring because I had a similar issue a year ago with losing power to the nox sensors but it seemed to be a wiring issue with the previous owner overflowing the def and corroding the wires.


You’ll need to take a ohmmeter to the CAN +/- lines on the Expansion Bus.

The Expansion Bus daisy chains and has the ECM, NOx sensors, reductant control module, PMS, and maybe more. It works just like the CAN on OBD2 but it’s not connected to there.

By daisy chain I mean you have 4 pins on each module (including the NOx). 2 of those pins are CAN IN +/-. 2 of them are CAN OUT +/-.

A connector issue can cause issues here. As can the incorrect NOx sensor. These NOx sensors come in 2 flavors.
1. Pass through sensor with CAN in and CAN put.
2. Terminal sensor with terminating resistor. Google what that means.

Because of the NOx sensor shortage I have seen some ‘refurbished’ sensors mix these up with symptoms exactly like you are describing. You will need to use a multimeter and verify the sensors are correct.

Youll also need a schematic of the expansion bus. The ECM and NOx sensor 2 are the terminating ends but verify that on your own don’t take my word for it.


----------



## Chederchad (Aug 14, 2021)

Snipesy said:


> You’ll need to take a ohmmeter to the CAN +/- lines on the Expansion Bus.
> 
> The Expansion Bus daisy chains and has the ECM, NOx sensors, reductant control module, PMS, and maybe more. It works just like the CAN on OBD2 but it’s not connected to there.
> 
> ...


Thanks for your help I'll have to get to that look tomorrow I don't have a garage to work in and have to dig out my multimeter.


----------



## Chederchad (Aug 14, 2021)

Traced it back to the Nox sensor 2 thanks to @Snipesy but know I have to do the actual hard part and find one.


----------



## Snipesy (Dec 7, 2015)

Chederchad said:


> Traced it back to the Nox sensor 2 thanks to @Snipesy but know I have to do the actual hard part and find one.


What was it doing?

I don't know how the Gen 2 Cruze is wired but on the LWN the NOx sensor is last in line. So, 4 wires go to it (power, ground, 2 can). And there is basically 0 reason it would be wired any differently.

So when you pop off the connector from the harness to the NOx 2 module those 2 CAN wires should have 120 ohm. If its infinity ohms or some high number its the wrong sensor. Likewise the 2 CAN wires on the harness should be 120 ohm.

Then on Sensor 1 the sensor module should have infinite resistance across the +/- (and 0 ohms across CAN IN + and CAN OUT +, same for CAN OUT/IN -). 
And each side of the harness should have 120.


----------



## Chederchad (Aug 14, 2021)

Welp she gone


----------



## Snipesy (Dec 7, 2015)

Chederchad said:


> Welp she gone
> View attachment 297811


RIP


----------



## Chederchad (Aug 14, 2021)

Found one CarID has a few of them on eBay. They recently added.


----------

