Hoping to get some assistance.

I bought a 2003 Hummer H2 in dire need of some love.

No dash warning lights for 1st week of driving. Had a mobile alarm guy come out and install a basic keyless entry. Simple power, ground, lock, unlock and flash lights.

We also found prior owner had cut up drivers side taillight wires so I only had right side lights working and no left.

He found the cut wire under the bumper and I had left lights again and working keyless entry.

Right after that I had ABS and traction control lights on my speedometer at first start-up of the engine...had not even driven it.

Ran codes and C0191 and C0161 came up.

I thought I read in a google search but now cant find it that someone had an issue like this after an alarm install and a door lock relay had to be changed? but cant find that again.

Anyone have any thoughts? perhaps taillight wire caused it?

 

DTC C0161
<a id="d74329e3">Circuit DescriptionThe stoplamp switch is a normally open switch, when the brake pedal is depressed the EBCM will sense battery voltage. This allows the EBCM to determine the state of the brake lamps. The EBCM sources 5 volts on the stop lamp switch signal circuit when the stop lamp switch is inactive. The voltage is supplied a ground path through the stop lamp bulbs.
<a id="d74329e12">Conditions for Running the DTCThe ignition switch is ON.
<a id="d74329e21">Conditions for Setting the DTC

• EBCM detects open in the brake signal circuit.
• Both brake lamps are faulty.
• The stoplamp switch input voltage is between 6.6 and 9 volts for 0.5 second.

<a id="d74329e48">Action Taken When the DTC SetsIf equiped, the following actions occur:

• A malfunction DTC will set.
• The EBCM stores this information-only DTC for as long as the condition is present.
• The ABS remains functional.
• The ABS indicator remains OFF.

<a id="d74329e84">Conditions for Clearing the DTC

• The condition for the DTC is no longer present and the DTC is cleared with a scan tool.
• The electronic brake control module (EBCM) automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

<a id="d74329e106">Diagnostic Aids

• It is very important that a thorough inspection of the wiring and connectors be performed. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction.
• Thoroughly inspect any circuitry that may be causing the complaint for the following conditions:
  • Backed out terminals
  • Improper mating
  • Broken locks
  • Improperly formed or damaged terminals
  • Poor terminal-to-wiring connections
  • Physical damage to the wiring harness
• Possible causes of this DTC are the following conditions:
  • A signal circuit of the stop lamp switch is open
  • The stop lamp switch is misadjusted
  • Verify proper stop lamp switch operation using the data list of the scan tool. As the brake is applied, the data list displays the stop lamp switch ON within 2.54 cm (1 in) of travel
  • All brake lamps are open
  • All brake lamp grounds are open
  • Circuit has a wiring problem, terminal corrosion, or poor connections
  • Loose or corroded EBCM ground
• If an intermittent malfunction exists refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

 

You can try removing ebcm ground on left outer frame rail approx. under the A pillar clean ground contact and reinstall.

 

Wow, thanks for the detailed feedback and your time. A lot of that might be over my head of trouble shooting...

The prior owner had three plugs unplugged to the air suspension. I plugged them back in thinking that would cure the issue and instead when running I could hear the air pump pumping non-stop, even when I shut the engine off and removed the key.

So I unplugged all three of them again as he had lifted the truck with springs and shocks and I assume removed the air shock.

Now I am getting the messages on the dash, "Service air suspension" which was not there before. Could this be causing the ABS/TC issue or how do I at least get rid of that message as it was not there before when they were already unplugged...

 

I also found an article that my ignition switch could cause ABS issues? being that my ABS lights came on after install of some stereo and alarm accessories attached to my ACC wire, could this be my issue?
2003 Chevrolet Trailblazer, Blower Not Working Any Speeds, Brake & ABS Lights On - Sparky's Answers

 

try disconnecting battery for about 15 min and then reconnect, in theory it should clear air suspension message as bcm will think its not equipped when it does not receive a state of health message from air suspension module.

 

If ignition switch was failing I would suspect more than just abs lights coming on, there would be other issues as well. check ign e fuse and seo b2 fuse in underhood fuse block

 

I have already gone through each and every fuse one by one to confirm this before posting, thanks.

I will do battery reset on air shocks.

I guess I will remove ABS module and send in for rebuild and hope that cures it. I just felt that since lights for it came on after NO driving right after accessories were installed, it was odd???

 

Due to the prior owner removing the air suspension, there were 3 plugs undone at the air module. Two around the back side and one flat pronged one going to a module. Should all 3 be left unplugged?

Also if these are all three unplugged does that mean the rear cargo air compressor wont function?

Also if the air hose is missing, what type or style is needed to buy to use on it?

Thanks HUMTECH. By any chance are you local to Orange County?

 

Yes you should unplug all connectors and then the air compressor wont function at all. You could wire a switch to the air compressor relay and manually turn it on to use rear inflator. No Im in western Canada so def not local. Not sure on hose ill look into it for you though