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Constant knock sensor code - 850R

Help, Advice and DIY Tutorials on Volvo's P80 platform cars -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, including 850 R, 850 T-5R, 850 T-5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

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jnewt
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Joined: 23 April 2020
Year and Model: 1991 244
Location: New York

Constant knock sensor code - 850R

Post by jnewt »

Knock sensor code tripped when I was going 30mph barely any throttle. When I clear the code it comes on immediately after restarting the car, within a second or two at most. Is it possible to reach the sensors without removing the manifold?

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erikv11
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Post by erikv11 »

It's really tough to reach them but you can.

This code is almost never an actual knock sensor problem - usually the wiring is damaged or connections are dirty.
'95 854 T-5R, Motronic 4.4, 185k
'98 V70, T5 tune-injectors-turbo, LPT engine, 304k, daily driver
'06 S60 R, 197k
'07 XC70, black, 205k
'07 XC70, willow green, 212k
'99 Camry V6 :shock: 153k
gone: '96 NA 850 210k, '98 NA V70 182k, '98 S70 NA 225k, '96 855 NA 169k

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abscate  
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Post by abscate »

What year is this? What code is being read? Many readers don’t map the p code to text correctly
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jnewt
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Year and Model: 1991 244
Location: New York

Post by jnewt »

abscate wrote: 23 Aug 2020, 04:07 What year is this? What code is being read? Many readers don’t map the p code to text correctly
1996, code P0326 - Knock Sensor 1 Circuit Range/Performance (Bank 1) is the exact text

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abscate  
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Post by abscate »

You will find very few clear this code with replacing the knock sensors, it’s usually poor running, wiring, or corrosion

Don’t overtughten the sensor or you will break them. Look up the spec torque, it’s low. Can’t be too loose either
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850oldschool
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Post by 850oldschool »

It’s possible to wriggle your hand in there. and also to view with a mirror. My wire was severed, perhaps by a rodent.

jnewt
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Post by jnewt »

abscate wrote: 23 Aug 2020, 08:39 You will find very few clear this code with replacing the knock sensors, it’s usually poor running, wiring, or corrosion

Don’t overtughten the sensor or you will break them. Look up the spec torque, it’s low. Can’t be too loose either
I reached my hand behind the intake manifold and wiggled the connector a bit and now no more code, I’m almost certain it’s the wiring and I’ll have to get in there to fix it. Thanks

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