Just replaced the knock sensors because rats chewed the wires and then got the H2 smogged. Several days later the engine light is back on and it doesn't perform at 100%. Driving home one day it started chugging along without much power and a siren inside the cab started going off. It was so loud I thought the other cars around could hear too. Just before I started to pull over because I thought it was going to stop running I down-shifted and it started to run ok and I made it home, I'm not sure when the alarm went off. I just checked the fault codes (5 of them) which reads: P0332 (knock sensor low voltage), P0327 (knock sensor low volt), P1258 (Engine Coolant Overtemperature - Protection Mode Active), P0327, and P0332.

Help me solve this please. What should I do?

Thanks in advance.

 

This is a 2005 H2 with about 125,000 miles.

 

MOVED. All H2 questions go in the H2 Section................... crazy like that.

The Hummer Forums Help & Suggestion Center, like it says, is not about any vehicle, but is the place to ask about how to use Forum Features, like posing a pic...

 

Hope you used genuine ACDelco knock sensors.... all the others are junk. Cheap ones got me once, only lasted a couple of months. The coolant overtemp is pretty critical too.

Since those are all related to sensors on the block that potentially use the block for a ground reference maybe some ground under the hood is failing.

 

I did get the AC delco knock sensors and installation wasn't too difficult. My reserve coolant tank was low and I added a little more than a quart to bring it up. Since it didn't take that much maybe the sensor it bad. Of course after I took the readings I reset the codes and the idiot light is off now so I'll run it again and see what happens. Before that I plan to go check all the connections to make sure they are solid. I'm not sure how long it will take to trigger the code again, but if it goes off again I'll change the temp sensor.

Any idea what that interior siren is all about?

Thanks MixManSC

 

I have no idea on any sort of siren on the inside of a vehicle. I guess one could put an alarm system siren inside if they happen to live in an area where people commonly ignore car alarms. Would make it incredibly unpleasant to be inside the vehicle of it was going off. lol

Only thing I can suggest would be to locate it.

 

probably a good idea to comb over wire looms and wires to see if anymore rodent damage is found, also check over/clean ground straps motor to firewall, frame to body front and rear.

 

aftemarket wiring= bad
aftermarket alarm going off INSIDE your vehicle = unbearable.

First thing you do is yank it out and repair all the wiring.