Help I’ve been obsessed with trying to figure this out for way too long lol - I feel like there has to be some related culprit. All parts related to each code have been replaced - the battery has been replaced. It appears that all of the codes have something to do with low voltage, resistance, circuit related, etc….please tell me that there’s a one simple fix that will clear away all of these codes that just keep coming back
P0449
P0060
P0161
P0327
P0332
C0161

I currently do not have the catalytic converter on the vehicle - maybe this is the oxygen sensor codes?
there’s so many other things electrical that do not work - front seat warmers, sunroof
the previous owner did install LED lights- and did a shady job- so maybe this has some things screwed up.

the ground strap under the hood - drivers side - engine to chassis (I think) - is questionable to me - but others have looked at it and said it was just fine

but I have no clue if that particular ground has anything to do with any of the error codes I’m getting…

figured you folks could probably help me out

I guess I’m saying PLEASE help me thanks a bunch - just sayin, be gentle with me if I left any info out

OH 2005 HUMMER H2
235,000ish miles

Ground strap looks frayed and corroded to me?

 

look to see in the wiring diagram if they share a power or ground. then trouble shoot from there. like what feeds them.

 

In either case I would replace that Ratty looking Ground lead. Buff out the connection point on both ends. I have see people use a Short battery cable as a ground lead. Not saying this would fix your issue, but Grounds are super important. If you search here one of our experts has posted a full list of grounds and their location as there are allot and immensely important.

 

@abbiemalcombutler
quickly running thro your DTC's

O2 sensors
P0060 is warning about sensor resistances being wrong
C0161 is warning Bank2 Sensor2 current is wrong, the algorithm may stop at the 1st sensor in the group hence just a single warning
Often pondered what errors there'd be with no CATS and no sensors, this is probably the answer. Not aware of a fix other than perhaps mounting the O2 sensors on extenders, but I have no details.

EVAP
P0049 relates to the EVAP solenoid being in the wrong state.

Stop Lamps
P0161 - Code says open circuit stop lamps or stop lamp switch. Could it be related to the LED lights you mentioned?

Transfer Case
P0327 - The electronic module is seeing an incorrect condition on the encoder i.e. a high voltage when a low voltage is expected.

Knock Sensor
P0332 - The signal from the knock sensor is less than expected for 10s

Related Grounds
N/A - O2 Sensor - Not relevant as not fitted
G102 - PCM general ground (Evap Solenoid) if this was bad it would be catastrophic
G104 - Knock Sensor
G310 - Transfer Case Shift Control Module (Encoder)
G300 - Stop Lamp Switch
G401 - Stop Lamps

Seems unlikely there's a common ground involved, possibly each DTC is genuine.

Perhaps focus on a single issue, say P0327 Transfer Case Encoder and try to resolve it.

 

I concur- I would also bet each code is valid. When you do the knock sensors - search the forum for great info. IF you get faulty replacement sensors- you will be doing it twice (wisdom), Start off with the cheap easy fixes & if making progress- do both knock sensors & harness (harness WILL fall apart in your hands) after you know prior codes are being resolved.... its the most involved one of your list I believe...