ECM diagnostic shunt codes

[Fuergrissa]

I apologize if this has been covered before. just bought a new (to me) 05' Impala 9C3 (Police) and got a CEL around mile 2 of ownership. On my other vehicle (90' 300ZX Turbo) I am able to check my own ECM codes by shunting two pins on the diagnostic port and counting short and long CEL flashes to get a code. I read on another forum that this is doable on my impala also but there were no details.

Basically which pins do I need to short, (a diagram showing which pins are which would be helpful also), and is there a list of ECM codes that I can compair it to after I get the code?

Thanks, and sorry if this is a repost.

[j cAT]

Originally Posted by Fuergrissa

I apologize if this has been covered before. just bought a new (to me) 05' Impala 9C3 (Police) and got a CEL around mile 2 of ownership. On my other vehicle (90' 300ZX Turbo) I am able to check my own ECM codes by shunting two pins on the diagnostic port and counting short and long CEL flashes to get a code. I read on another forum that this is doable on my impala also but there were no details.

Basically which pins do I need to short, (a diagram showing which pins are which would be helpful also), and is there a list of ECM codes that I can compair it to after I get the code?

Thanks, and sorry if this is a repost.

I would buy a scanner or go to autozone to get the codes retrieved...

[Fuergrissa]

P0171 Bank 1 Lean

Motor has almost no vacuum lines, so I dont think I have a vacuum leak. fuel filter would cause lean condition on both banks, but is still a possibility. I'm thinking either an exhaust leak before the bank 1 o2 sensor, or a bad injector. Any tips are welcome I'll post again if I'm able to figure it out/fix it.

[Iflylow]

As the previous poster said, get it scanned. It is not possible to jump pins to figure out the code on the newer OBDII vehicles.
Do you have any driveability problems, or any symptoms of a problem besides the CEL?

[richtazz]

Just to clarify, you cannot jump pins on 96-newer OBD-II vehicles, you must use a scan tool to retrieve codes.

On a generic scan tool, this code will come up as bank 1, but since there is only 1 pre-cat oxygen sensor on your car, there is no bank 2 on your car.

Codes like system lean are very hard to diagnose, as many little things can add up to trip this code. There is no "smoking gun" part that will fix it. My suggestion would be to clear the code and see if it comes back. Occasionally, you can get ghost codes that pop up due to electrical anomalies or a one time odd "perfect storm" of variables that will cause it to trip. If the code comes back, then I would start looking for vacuum leaks first.