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Author Topic: How to test knock sensor and wires?  (Read 21573 times)

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tkm509

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How to test knock sensor and wires?
« on: 12/30/10 04:42 PM »

I replaced both sensors about 4 months ago. have had several knock sensor codes this past week, all showing bank 2 low input. I also replaced the connector, from Napa, for the rear sensor when I replaced both sensors. I am wondering if I have a bad sensor or connection, or if there is a problem in the wiring. Is there a way to test the sensor and the harness? I still plan on replacing the sensors again, and the harness(GM this time)
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2002 Avalanche
Mods- Cold air intake, FTDRL, Amber DRL, ALL 4 on, HID, Tailgate assist

TXSZ66AVLANCHE

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Re: How to test knock sensor and wires?
« Reply #1 on: 12/30/10 05:09 PM »

You are supposed to change the harness as well... The factory harness is a weak point in the system as well as water getting into the knock sensors. Also if you wash your engine, its a good time to stop doing it.
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tkm509

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Re: How to test knock sensor and wires?
« Reply #2 on: 12/30/10 06:21 PM »

I only replaced the connector that was bad. I will replace the whole harness tomorrow. I just want to know if there is a way to test the components before I replace them again( which I will do), and after I install the new parts.
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2002 Avalanche
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TXSZ66AVLANCHE

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Re: How to test knock sensor and wires?
« Reply #3 on: 12/30/10 07:38 PM »

I dont think there is any way to test, but there is a TSB posted somewhere on how you are supposed to build like a wall of silicone around the knock sensors to keep water and debris out of them.
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2003 Suburban-GMT900 Brakes, BB Tuned, Dual Batteries, DL3 Mirrors , E-Fans, Eibach Sway Bars
2003 Silverado- Ranch Hand Push Bars, Work Horse and guinea pig
2004 Avalanche- LS1 5.7, GMT900 Brakes, BB tuned, Efans, Leveled, Dual Batteries, Painted Door Handles, Detroit TrueTrac, Eibach Sway Bars
2005 Silverado RCSB- Currently Stock
1995 S10- Race Truck In Progress!
 

tkm509

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Re: How to test knock sensor and wires?
« Reply #4 on: 12/30/10 07:42 PM »

I dont think there is any way to test, but there is a TSB posted somewhere on how you are supposed to build like a wall of silicone around the knock sensors to keep water and debris out of them.

thanks. read and done TSB first time around.



Does anyone else know of test for the knock sensors?
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2002 Avalanche
Mods- Cold air intake, FTDRL, Amber DRL, ALL 4 on, HID, Tailgate assist

ItsStopher

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Re: How to test knock sensor and wires?
« Reply #5 on: 01/02/11 05:41 AM »

DO NOT TAP ON PLASTIC PARTS


Connect the DMM between the affected KS signal circuit on the sensor side and a good ground. Set the DMM
to the 400 mV AC hertz scale. Tap on the engine block near the affected KS while observing the signal
indicated on the DMM.

Is any signal indicated on the DMM while tapping on the engine block near the KS? If so then the KS and wires are good up to that point.

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tkm509

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Re: How to test knock sensor and wires?
« Reply #6 on: 01/04/11 06:59 PM »

rear KS was bad, no signal before or after knocking. with or without the harness. replaced them both and the harness on Thursday, so far no issues! I don't ash the engine but do go thru the car wash sometimes, and the KS were both dry, so the TSB did work.(replaced KS in June)
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2002 Avalanche
Mods- Cold air intake, FTDRL, Amber DRL, ALL 4 on, HID, Tailgate assist

J_One17

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Re: How to test knock sensor and wires?
« Reply #7 on: 02/02/11 05:58 PM »

Hey Guys I'm now to the fourm hows everyone doing. Well I had a probelm with my bank 2 KS so i went ahead and replaces both of them a week ago and had no problems till now. Both of them are now giving me codes.It looks like i should have also replace the harness. I looked around but havnt had luck finding it at any auto parts store. Does anyone have a Part numbe or is it a something i have to get at GM?
And just in case Its for my 02 Avalanche Z71 5.3 150k miles
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02 Z71 Avalanche, Bilstiens 5100, Airlift  1000 with air system.BFG All Terrain Ko2 , Spectra CAI, MBRP Back cat kit,procomp 2.5' leveling kit, N-fab Nerf Bar, 20 in led bar, 2 led pods,50' Curved LED light bar

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shehatesxboxlive

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Re: How to test knock sensor and wires?
« Reply #8 on: 02/10/11 12:05 AM »

I replaced both sensors about 4 months ago. have had several knock sensor codes this past week, all showing bank 2 low input. I also replaced the connector, from Napa, for the rear sensor when I replaced both sensors. I am wondering if I have a bad sensor or connection, or if there is a problem in the wiring. Is there a way to test the sensor and the harness? I still plan on replacing the sensors again, and the harness(GM this time)
IF YOU REPLACED WITH AFTER MARKET SENSORS LIKE I DID,THEY DO NOT WORK.YOU HAVE TO GET THE SENSORS AND THE  WIREHARNESS FROM THE DEALER.I FOUND OUT THE HARD WAY AND HAD TO REPAIR IT 3 TIMES.THE SMOG GUY TOLD ME NOT TO BUY AFTER MARKET KNOCK SENSORS AND TO BUY A NEW  WIREHARNESS.SO TO SAVE MONEY I PURCHASED AFTER MARKET SENSORS AND CHECK ENGINE LIGHT STILL ON=   FAILED. SECOND TIME I INSTALLED SENSORS FROM DEALER BUT DIDNT CHANGE WIREHARNESS, CHECK ENGINE LIGHT WAS STILL ON =FAILED.WENT TO DEALER GOT WIREHARNESS AND INSTALLED IT, CHECK ENGINE LIGHT WAS OFF AND IT PASSED.--IF YOUR GOING TO FIX YOUR KNOCK SENSOR PROBLEM TRUST ME DO IT RIGHT THE FIRST TIME AND BUY OEM DEALER PARTS ITS A MUST FOR THE KNOCK SENSOR FIX.(I TRY TO SAVE A BUCK AND IT BIT ME IN THE ASS HARD)   GOOD LUCK!!!!!
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