So after about an hour of driving I got this code which indicates there is something up with my cyl 3 fuel injector. I drove the car all morning and to lunch and all was well. After lunch I get into the car and the trac light is on.. I go to leave and the car is running on what feels like 7 cylinders and sounds like a subaru. Shortly there after the engine light comes on. When I try to get into boost it breaks up and spits and sputters.

I went back to my garage and checked the plug to the injector on that cylinder, cleared the codes and attempted a restart.

Well now the trac light and engine lights are both off, however it appears clearing the codes has made it so my car wont stay running. It starts up and stalls out a couple of seconds later.

What gives?

 

P0203 Injector 3 Control Circuit ECM

Conditions for Setting the DTC
• The control module detects an incorrect voltage on the fuel injector control circuit.

• The above condition is met for 1 second.

So, ohm out the #3 injector, and the injectors next to it to check the injector ohm value, then start checking the wiring injector connector and wiring all the way back the ECM and ground points.



If you suspect the injector, then change it to another location (remember to lube the O ring before you reinstall them) and see if the code problem follows the injector to it's new location, or stays with the wiring for the injector isntead.


Left front to back 1-3-5-7
Right front to back 2-4-6-8

So the injector in question is the passenger side, second one back from the front.

 

thanks for the super information. Wouldnt the injector be on the left side?

 

how do I check the wires at the injectors for continuity

 

On the ejectors connectors, ecm is controlling the ground loop, so you are checking both sides of the connectors to make sure that you don't have a continuity to ground on either side to begin with (shorted grounded wire).

Next, on the positive side back to the fuse box, pull the fuse in the engine bay fuse block, and make sure that you do have clean continuity to it from the injector connector.

Lastly, need to know what year your vet is/ what motor/what ECM (if e38 or E40), and I can tell you which pin on the ECM connector to test the ground connector side back to the ECM for problems in that part of the wire run on a continuity test.




On an E40 for a LS-2, it's connector C2, pin #39 for injector 3 control
On a E38 for a ls-3 and ls-7, it's connector x2, pin #38 for injector 3 control
On a E38 for a LS-9, it connector X2, pin #16 for injector 3 control

And the Ecm is located in the back of the fender well on the passenger front side of the car. To get to it, you just need to jack up the passenger front side, remove the front tire, then remove the back fender well cover via the pull pins you can see holding it in place on the wheel well cover, and then the 3 bolts on under the car on the bottom of it.



Note, E40 had 3 connectors, while a E40 only has two.


But before you go this deep, just swap injector 3 and 1 in the intake manifold, plug the injector connectors back in there correct positions, and see if the problem is following the injector to start with.

 

Thank you but I am confused about firing order. On google and in your first post I think cyl 3 is listed on left bank.

Here is a quote from your first post....

Left front to back 1-3-5-7
Right front to back 2-4-6-8


Since my code indicated cyl 3 I thought it was left bank?

 

Had a brain fart , but this should be better to show you where the # 3 cylinder and injector location.





As for the ECM pin numbers for the #3 injector control wire, your golden on them, since I pulled them from the GM service repair manual.

 

So ive checked the ohms on all injectors on the left bank... All measure the same. No anomalies there. I checked to see if i have 12v to the injector with the key on and i do...

I suppose now i should check continuity and to see if the injector is pulsing when running?

 

Take a look at the spark plug wires in that area...if one is loose it may be trying to ground through another wire in that same area and messing with the computer. A loose spark plug wire makes the engine run badly, as you are experiencing. Easy thing to check and rule out.

 

so after all the checks she drove well but then ended up throwing the p0203 code again...

I got out pulled the plug off the injector and put it back on and the code went out and the car ran fine again for the rest of the drive...

I think the plug isnt seating properly for some reason.

 

Start here to clean both the injector socket electrical tabs and the connector spade fittings,




Put some dielectrical grease on the connectors to make sure they are getting a good contact,


And once you have the connector clipped back on, push the wires into the connector to make sure that it spade tabs are all the way seated on the plug spade connector.


If this is not solving the problem, then you may have to pop the spade connectors out of the connector housing, and make sure that the wires have a good connection to the metal connectors (hence someone may have pulled the connector off via the wires, and not the connectors, and now have a problem between the connectors to wires isntead.



And no, it not hard since you can remove the connector's via the connector housing with a sewing pin, and if push comes to shove, a solder the wires to the crimp type back pieces so they are making a good connection to the connectors. Also you can check the spring part of the connector to bend it back out, so once its inserted back into the connector, it stays forward in place. Also, you can tweak the connector so it making a good connection to the injector spade tab.

 

Was this ever resolved?
I have a very similar problem.

 

resistant test is static --> not under a load!!..means nothing most of the time... for real ]on time live test to be a 100% sure ....it takes a low amp probe an ocilliscope to nail it with amp wave form...find a real shop who can do that... rest of it is myth and guessing

 

help i'm having somewhat the same issue when i wash my C6 or when it rains.