Fault code 12 and 27

[Tomas]

Hello Everyone

Started up my car today and it ran very bad and the check engine light was on. I checked the codes and found that it is code 12 and 27

#12 Direct battery input to PCM was disconnected within the last 50 key-on cycles?????????

#27 Injector 1 output driver does not respond properly to the contorl signal?????


What can be wrong??? where shall I start to look??

best regards

Tomas

 

[Bill B]

How long since you last ran the car?

 

[Tom F&L GoR]

You could switch injector #1 to another location and see if the DTC follows the injector. Then you obvious have a bad injector. If it stays with injector #1, sounds like you have a bad Powertrain Control Module or Ignition Control Module. Reading from the service manual:

The PCM opeates injectors 2, 3, 4, 6, 7, 8, 9, and 10. At the instruction of the PCM, the ICM operates injectors 1 and 5.

You could also check for constant 12v at the injector; the system grounds the negative to energize the injector. The wire for Injector #1 is K11 18WT/DB*, or an 18 gauge white wire with a dark blue stripe.

I hope you have a service manual.

 

[Tomas]

Hello Bill and Tom

Thanks for the replies. I haven´t drive with my car for about one week before this
fault codes came up (Bought a Hummer H2). Yes I have a service manual so I will try to find the cables and do some measuring.

rgds

Tomas