Knock Sensor

2004 FORD F-150
Avatar
TBERNDTSON
  • MEMBER
  • 1 POST
Check engine light on, computer show knock sensor code. If the 5.4 engine has 2 of them??
Sep 25, 2010 at 3:13 PM
Advertisement
Avatar
KASEKENNY
  • CERTIFIED EXPERT
  • 18,907 POSTS
That is correct. You have one for each bank. Your code should dictate which bank the code is for which will tell us which sensor the issue is with. I am attaching the info on these sensors for your review. Let us know what the actual code is and we can get more info if needed. Thanks

Here is a guide as well that will help with some general information:

https://www.2carpros.com/articles/how-a-knock-sensor-works
Nov 27, 2020 at 6:25 PM
Avatar
FLICSTER
  • MEMBER
  • 1 POST
where is the knock sensor bank 1 located?
Dec 7, 2020 at 4:39 PM (Merged)
Advertisement
Avatar
STEVE W.
  • CERTIFIED EXPERT
  • 15,113 POSTS
The knock sensor is under the intake manifold. You remove the intake and unscrew the sensor. There is a pinpoint test you can do.

DG1- CHECK KS SENSOR RESISTANCE

Note: Refer to the PCM connector pin numbers in the beginning of this pinpoint test.

Disconnect KS, measure resistance through the KS harness connector pins
Is resistance between 4.39 and 5.35 megaohms?
Yes = GO to DG2
No = For resistance less than 4.39 megohm: GO to DG3

DG2 - CHECK FOR OPEN OF KS CIRCUIT BETWEEN KS HARNESS CONNECTOR AND PCM HARNESS CONNECTOR
Disconnect PCM.
Measure resistance of the KS+ circuit between the PCM harness connector pin and the KS harness connector.
Measure resistance of KS- circuit between the PCM harness connector pin and the KS harness connector.
Is each resistance less than 5.0 ohms?
Yes = REPLACE KS.
No = REPAIR open circuit.

DG3 - CHECK KS CIRCUIT FOR SHORT TO GROUND IN HARNESS
Measure resistance between the KS- circuit at the PCM harness connector and chassis GND.
Measure resistance between the KS+ circuit at the PCM harness connector and chassis GND.
Is each resistance greater than 10,000 ohms?
Yes = GO to DG4
No = SERVICE short circuit.

DG4 - CHECK KS CIRCUITS FOR SHORT TO POWER IN HARNESS

Disconnect PCM.
Turn Key on.
Measure voltage between the KS+ circuit at the PCM harness connector and battery negative post.
Is the voltage less than 0.5 volt?
Yes = REPLACE PCM See: Programming and Relearning
No = SERVICE short circuit.

DG5 - CHECK KS CIRCUIT FOR INTERMITTENT FAULT
Key off.
Measure the resistance for KS+ between the PCM and KS harness connectors, while viewing the ohm meter, grasp the vehicle harness as close to the knock sensor(s) as possible. Shake and bend a small section of the harness from the KS sensor to the PCM.
Measure the resistance for KS- between the PCM and KS harness connectors, while viewing the ohm meter, grasp the vehicle harness as close to the knock sensor(s) as possible. Shake and bend a small section of the harness from the KS sensor to the PCM.
Tap the PCM and KS connectors if possible.
Are the resistance readings changing?
Yes = ISOLATE fault and SERVICE as required.
No = GO to DG6

DG6 - CHECK INTERNAL PCM RESISTANCE

Disconnect knock sensor (KS) harness connector.
Measure resistance between KS+ and KS- pins through the harness connector.
Is resistance greater than 10,000 ohms?
Yes = REPLACE KS. If concern is still present, REPLACE PCM See: Programming and Relearning).
No = REPLACE PCM See: Programming and Relearning.

Dec 7, 2020 at 4:39 PM (Merged)
Avatar
MARK BINKLEY
  • MEMBER
  • 1 POST
Engine Mechanical problem 6 cyl Two Wheel Drive Manual 237214 miles

I would like to know where the knock sensor is located on my 2001 F-150. Can you help me out with this puzzle? I love this site
Dec 9, 2020 at 8:54 AM (Merged)
Avatar
STRAILER
  • CERTIFIED EXPERT
  • 53,854 POSTS
The knock sensor for the v6 engine is at the rear of the engine block while the v8 engine has the sensor under the intake manifold. Here are some diagrams so you can see what I am talking about. (below)

Please let us know if you need anything else to get the problem fixed.

Cheers, Ken
Dec 9, 2020 at 8:54 AM (Merged)
Avatar
TOM GARDELLA
  • MEMBER
  • 1 POST
I have heard the knock sensor will be located on the right front of the engine for the 2001 F150 4.2L V6 ? is this correct and could anyone post a diagram indicating its exact position? thanks
Dec 9, 2020 at 8:54 AM (Merged)
Avatar
DANNY L
  • CERTIFIED EXPERT
  • 5,648 POSTS
Hello, I'm Danny.

Yes, you are correct. I've attached a picture below showing its location.Hope this helps and thanks for using 2CarPros.
Dec 9, 2020 at 8:54 AM (Merged)
Avatar
BIGFOOT26
  • MEMBER
  • 3 POSTS
I have tried an tried to find and watch videos for this repair. And or pictures but cannot get a direct answer for the location for the sensor. All I have found was by the starter I have looked an cannot find this. Any information an pictures would greatly help.
Dec 9, 2020 at 8:54 AM (Merged)
Avatar
JACOBANDNICKOLAS
  • CERTIFIED EXPERT
  • 110,175 POSTS
Hi and welcome to 2carpros.com

It will be mounted to the cylinder head, either the front or rear. (if I recall it's the driver's side rear head) I attached a picture of its location to help you find it.

Let me know if this helps of if you have other questions.

Take care,
Joe
Dec 9, 2020 at 8:54 AM (Merged)
Avatar
BIGFOOT26
  • MEMBER
  • 3 POSTS
Thank you very much
Dec 9, 2020 at 8:54 AM (Merged)
Avatar
JACOBANDNICKOLAS
  • CERTIFIED EXPERT
  • 110,175 POSTS
Hi:
You are very welcome. Here are directions for replacement. The attached pic correlates with the directions.

_________________________

2000 Ford Truck F 150 2WD Pickup V6-4.2L VIN 2
Procedures
Vehicle Powertrain Management Sensors and Switches - Powertrain Management Sensors and Switches - Computers and Control Systems Knock Sensor Service and Repair Procedures
PROCEDURES
REMOVAL



pic 1



1. Remove the Knock Sensor (KS).
1 Disconnect the electrical connector.
2 Remove the bolt and the KS.

INSTALLATION
1. To install, reverse the removal procedure.

______________________

Take care and feel free to come back anytime.

Joe
Dec 9, 2020 at 8:54 AM (Merged)
Avatar
  • MEMBER
  • 2 POSTS
V8 two wheel drive automatic 125,000 miles.

Where does the knock sensor plug into the front of the engine or the back? i cannot find the plug.
Dec 9, 2020 at 8:54 AM (Merged)
Avatar
BLUELIGHTNIN6
  • CERTIFIED EXPERT
  • 16,542 POSTS
The knock sensor will be located on the right front of the engine for the 4.2L and on the right side of the engine for the 4.6L and 5.4L engines. I can post diagram if you specify your correct engine size.
Dec 9, 2020 at 8:54 AM (Merged)
Avatar
  • MEMBER
  • 2 POSTS
The engine is a 4.6 V8.
Dec 9, 2020 at 8:54 AM (Merged)
Avatar
BLUELIGHTNIN6
  • CERTIFIED EXPERT
  • 16,542 POSTS


https://www.2carpros.com/forum/automotive_pictures/261618_Noname_1656.jpg

Dec 9, 2020 at 8:54 AM (Merged)
Avatar
JGANAWAY
  • MEMBER
  • 42 POSTS
Where is the knock sensor located on a 4.9?
Dec 9, 2020 at 8:54 AM (Merged)
Avatar
KASEKENNY
  • CERTIFIED EXPERT
  • 18,907 POSTS
I attached the process from the manual to replace this sensor. Let me know if you need more info and we can dig something up. Check out the diagrams (Below). Please let us know what happens. Thanks
Dec 9, 2020 at 8:54 AM (Merged)
Avatar
ROYF
  • MEMBER
  • 7 POSTS
My truck is running erratically (no power, jerking, running very rich, etc.). I thought it may be the knock sensor, however when I checked the voltage to the knock sensor with the key on (engine not running) it was 1.9 volts. The Haynes manual states that it should be about 5 volts. Could this be a short or maybe a bad power control module?

Any help would be most appreciated!!!
Dec 9, 2020 at 8:55 AM (Merged)
Avatar
HMAC300
  • CERTIFIED EXPERT
  • 48,601 POSTS
check fue lpressure first if fuel injected, autoparts rent gauge then check for a vacuum leak and yes if the voltage is not high enough it could be a bunch of things like a bad ecm an dor a shorted wire. but you should scan for codes first if you can
Dec 9, 2020 at 8:55 AM (Merged)
Avatar
ROYF
  • MEMBER
  • 7 POSTS
I thought about fuel pump, however the truck is running extremely rich. I scanned for the codes with an OBD and it showed the following: 22, 23, 25, 34, 72 and 73. I replaced the Throttle Position Sensor, the MAP sensor, the EGR Sensor and the O2 Sensor. I looked for a knock sensor, but could not find one. I retried the OBD and came up with: 22, 23, 31, 42, 72 and 73. The truck still performs very badly with a lot of backfiring into the intake if you try to accelerate too fast. I check the timing several times and it is right on the money. Any suggestions

RoyF
Dec 9, 2020 at 8:55 AM (Merged)
Avatar
ROYF
  • MEMBER
  • 7 POSTS
If there is a corroded connection in the PCM, will it show an error code for that, or will it only show an error code for the pins that are corroded? Should I go ahead and take the PCM off and check for corrosion? Also is there a way for me to check for vacuum leaks that is easier, I am deaf in one ear and are unable to detect leaks by sound. Thanks again!!

Roy F
Dec 9, 2020 at 8:55 AM (Merged)
Avatar
HMAC300
  • CERTIFIED EXPERT
  • 48,601 POSTS
a few of those codes we don'thave in our manualsbut we do have a few so the others may be false codes. in your Haynes manual you neeed to do test e for egr, g for map sensor which could be a bad hose and collapsing and I for tps. tehegr cold be partially clogged and staying open leaving a gad/rough idle or clogged passages or the solenoid for it. and yes corroded pins can caue a lot of problems. but be very careful and try not to bend any. when you put it back together put some dielctric compound in there to help alleviate that. matbe for the vacuum test is hook up a tach and spray choke cleaner if the tach goes up you found it.
Dec 9, 2020 at 8:55 AM (Merged)
Avatar
ROYF
  • MEMBER
  • 7 POSTS
I checked the egr valve and it was plugged solid. Picked up new one and put it on, I will reset timing to see how it performs. Thanks for your help!!!
Dec 9, 2020 at 8:55 AM (Merged)
Avatar
ROYF
  • MEMBER
  • 7 POSTS
Well, I replaced the EGR Valve and put it on the OBD and it came up with these codes 22, 23, 31, 42, 63, 72 and 73.
22-MAP Sensor voltage out of spec
23-Throttle Position Sensor voltage out of spec
31-EGR Valve Position Sensor voltage out of spec
42-O2 Sensor always rich does not switch
63-Throttle Position Sensor voltage too low
72 and 73 have to do with not enough change with vacuum and throttle during Dynamic Response portion of test. I have tested the fuel pump and pressure is fine. In addition, although timing is perfect when you accelerate you get backfiring through the intake, like it is out of time.
Any suggestions?
Dec 9, 2020 at 8:55 AM (Merged)
Avatar
HMAC300
  • CERTIFIED EXPERT
  • 48,601 POSTS
check for a broken/bent pushrod and or a broken valve spring along with a worn camshaft. if the camis worn the rocker won't go up and down as much as other ones.if it backfires through intake like you can actually see it then it's an exhaust valve not opening.
Dec 9, 2020 at 8:55 AM (Merged)
Avatar
ROYF
  • MEMBER
  • 7 POSTS
I understand, but how would that account for the air/fuel mixture being so rich. I really mean rich, the gasoline smell and black smoke out of the exhaust seems to be from more than one cylinder or valve. Acceleration is jerky as well sometimes, like the fuel is being restricted.
Dec 9, 2020 at 8:55 AM (Merged)
Avatar
HMAC300
  • CERTIFIED EXPERT
  • 48,601 POSTS
because if you aren't opening the valves it creates a miss so it gets to much fuel. also I have suggested testing fue pressure with a gauge and have not received an answer if your regulator is screwed up it will do that as well. I have no further comments or suggestions.
Dec 9, 2020 at 8:55 AM (Merged)
Avatar
ROYF
  • MEMBER
  • 7 POSTS
I am sorry, I did check the fuel pressure with motor off and on demand and it performed according to specifications. I have noticed that the motor runs somewhat better when cold, it is when it heats up that I get the surging and hesitation.
Dec 9, 2020 at 8:55 AM (Merged)
Avatar
HMAC300
  • CERTIFIED EXPERT
  • 48,601 POSTS
check compression and vor vacuum leaks I have not further suggestions
Dec 9, 2020 at 8:55 AM (Merged)