VSS Testing
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Senior User
Joined: Oct 2007
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From: Howard City, Mi
VSS Testing
Checked some things out today.With everything plugged in the spedo doesn't work and the tranny slams into gear and then in and out of overdrive and the OD light blinks. Unplugged the RABS module everything the same,plugged it back in.Unplugged the speed control module everything the same,plugged it back in.
Now this truck has a plug under the dash that has a red/pink wire and a green/black wire, I am thinking this is for VSS?? at this plug with everything plugged in I get 0 ac volts at a stop and .136 ac volts going down the road. Do I check for continuity from this same plug just so I can rule out any shorts.
Do I need to have an analog meter when doing this, I have a Blue-Point EEDM512CK Automotive Digital Multimeter.
Now this truck has a plug under the dash that has a red/pink wire and a green/black wire, I am thinking this is for VSS?? at this plug with everything plugged in I get 0 ac volts at a stop and .136 ac volts going down the road. Do I check for continuity from this same plug just so I can rule out any shorts.
Do I need to have an analog meter when doing this, I have a Blue-Point EEDM512CK Automotive Digital Multimeter.
Fleet Owner
Joined: Aug 2005
Posts: 23,666
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From: Easton,Ks
For your 1999 F-series truck:
CHECK RAB SENSOR CIRCUITRY RESISTANCE WITH SENSOR CONNECTED.
Measure the resistance between anti-lock brake control module C222-3, circuit 519 (LG/BK), harness side and anti-lock brake control module C222-10, circuit 523 (RD/PK), harness side while shaking the wire harness.
Is the resistance steady and between 800 and 3,500 ohms?
NO: goto K4 below.
YES:
CHECK REAR ANTI-LOCK BRAKE SENSOR CIRCUITRY FOR SHORT TO GROUND
Measure the resistance between anti-lock brake control module C222-3, circuit 519 (LG/BK), harness side and ground; and between anti-lock brake control module C222-10, circuit 523 (RD/PK), harness side and ground.
Are the resistances greater than 10,000 ohms?
No:
REPAIR circuit 523 (RD/PK) and 519 (LG/BK) as necessary.
Yes:
K4 CHECK REAR ANTI-LOCK BRAKE SENSOR with the sensor unplugged.
Measure the resistance between the rear anti-lock brake sensor pins (component side).
Is the resistance between 800 and 3,500 ohms?
Yes:
REPAIR circuit 519 (LG/BK), and circuit 523 (RD/PK) as necessary.
No:
INSTALL a new rear anti-lock brake sensor.
CHECK RAB SENSOR CIRCUITRY RESISTANCE WITH SENSOR CONNECTED.
Measure the resistance between anti-lock brake control module C222-3, circuit 519 (LG/BK), harness side and anti-lock brake control module C222-10, circuit 523 (RD/PK), harness side while shaking the wire harness.
Is the resistance steady and between 800 and 3,500 ohms?
NO: goto K4 below.
YES:
CHECK REAR ANTI-LOCK BRAKE SENSOR CIRCUITRY FOR SHORT TO GROUND
Measure the resistance between anti-lock brake control module C222-3, circuit 519 (LG/BK), harness side and ground; and between anti-lock brake control module C222-10, circuit 523 (RD/PK), harness side and ground.
Are the resistances greater than 10,000 ohms?
No:
REPAIR circuit 523 (RD/PK) and 519 (LG/BK) as necessary.
Yes:
K4 CHECK REAR ANTI-LOCK BRAKE SENSOR with the sensor unplugged.
Measure the resistance between the rear anti-lock brake sensor pins (component side).
Is the resistance between 800 and 3,500 ohms?
Yes:
REPAIR circuit 519 (LG/BK), and circuit 523 (RD/PK) as necessary.
No:
INSTALL a new rear anti-lock brake sensor.
Fleet Owner
Joined: Aug 2005
Posts: 23,666
Likes: 301
From: Easton,Ks
Ok 1995.
Put jack stands under the rear axle.
There should not be a plug under the dash for this system other than the plug for the RABS module.
The plug should be at the drivers hood henge just aft of the EEC Self-Test plug.
Put a A/C volt meter on this plug, it only has two wires.
Run the truck up to 30 MPH.
Does the voltage increase smoothly and continuously from 0 to approximately 3.5 volts AC as vehicle speed increases from 0 to 48 km/h (0 to 30 mph) at the plug?
If not unplug the RABS module and see if you get it now.
If not unplug the PSOM also, do you get the VAC now?
If not change out the VSS sensor at the rear end.
If the wiring is OK and you still do not get the voltage reading then you may have a bad tone ring or bearings in the rear end.
Put jack stands under the rear axle.
There should not be a plug under the dash for this system other than the plug for the RABS module.
The plug should be at the drivers hood henge just aft of the EEC Self-Test plug.
Put a A/C volt meter on this plug, it only has two wires.
Run the truck up to 30 MPH.
Does the voltage increase smoothly and continuously from 0 to approximately 3.5 volts AC as vehicle speed increases from 0 to 48 km/h (0 to 30 mph) at the plug?
If not unplug the RABS module and see if you get it now.
If not unplug the PSOM also, do you get the VAC now?
If not change out the VSS sensor at the rear end.
If the wiring is OK and you still do not get the voltage reading then you may have a bad tone ring or bearings in the rear end.
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Senior User
Joined: Oct 2007
Posts: 168
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From: Howard City, Mi
Sorry again, it is a 1996 F-150. Give the wrong info and you will indeed get the wrong info back-Dang it lol I feel like a ra-Tard.
Thread Starter
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Senior User
Joined: Oct 2007
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From: Howard City, Mi
SubFord, I can not find this self-test plug??? What would the chances of this being a half '97 model year? It has an OBD11 test plug under the dash,are the '96 OBD11. I really don't know-really confused and trying to figure this out for my father inlaw I hooked up my new scanner and it isn't reading any mph either. I am sorry if I am making you mad but I can't find that plug.
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Fleet Owner
Joined: Aug 2005
Posts: 23,666
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From: Easton,Ks
Yes all the 1996 F150 5.0L are OBD-II.
It does not look like the 5.0 has the test plug under the hood.
You may have to unplug the RABS module and do the test with the LG/BK wire 519 at pin #3 and the R/PK wire 523 at pin #10 of the RABS plug.
It does not look like the 5.0 has the test plug under the hood.
You may have to unplug the RABS module and do the test with the LG/BK wire 519 at pin #3 and the R/PK wire 523 at pin #10 of the RABS plug.
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Thread Starter
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Senior User
Joined: Oct 2007
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From: Howard City, Mi
Checked some things out today.With everything plugged in the spedo doesn't work and the tranny slams into gear and then in and out of overdrive and the OD light blinks. Unplugged the RABS module everything the same,plugged it back in.Unplugged the speed control module everything the same,plugged it back in.
At the plug side of the RABS module I get 0 ac volts at a stop and .136 ac volts going down the road. Same thing with a new speed sensor. What is the clearance suppose to be between the sensor and the exciter ring? If it is the exciter ring where can I get a new one?
At the plug side of the RABS module I get 0 ac volts at a stop and .136 ac volts going down the road. Same thing with a new speed sensor. What is the clearance suppose to be between the sensor and the exciter ring? If it is the exciter ring where can I get a new one?
Fleet Owner
Joined: Aug 2005
Posts: 23,666
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From: Easton,Ks
I would unplug the PSOM and the RABS module and recheck the voltage.
If the voltage is right with the PSOM unplugged then I would replace the PSOM.
Here is the gap measurements, K11.
K11 MEASURE RABS SENSOR AIR GAP
Remove rear axle differential cover.
Measure the shortest distance from the RABS sensor pole piece to the teeth on the RABS sensor ring.
Rotate the axle 60-90 degrees.
Repeat the two previous steps five times for a total of five measurements.
Are all measurements between 0.127mm (0.005 inch) and 1.14mm (0.045 inch) and within 0.254mm (0.010 inch) of each other?
Yes
GO to «K13».
No
Measurements are not between 0.127mm (0.005 inch) and 1.14mm (0.045 inch). CHECK for foreign material under RABS sensor mounting flange and on carrier housing. REPLACE RABS sensor. GO to «K12».
Not all measurements are within 0.254mm (0.010 inch) of each other. REPLACE RABS sensor ring. GO to «Pinpoint Test S» to verify concern is resolved.
If the voltage is right with the PSOM unplugged then I would replace the PSOM.
Here is the gap measurements, K11.
K11 MEASURE RABS SENSOR AIR GAP
Remove rear axle differential cover.
Measure the shortest distance from the RABS sensor pole piece to the teeth on the RABS sensor ring.
Rotate the axle 60-90 degrees.
Repeat the two previous steps five times for a total of five measurements.
Are all measurements between 0.127mm (0.005 inch) and 1.14mm (0.045 inch) and within 0.254mm (0.010 inch) of each other?
Yes
GO to «K13».
No
Measurements are not between 0.127mm (0.005 inch) and 1.14mm (0.045 inch). CHECK for foreign material under RABS sensor mounting flange and on carrier housing. REPLACE RABS sensor. GO to «K12».
Not all measurements are within 0.254mm (0.010 inch) of each other. REPLACE RABS sensor ring. GO to «Pinpoint Test S» to verify concern is resolved.
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From: Central Mississippi
I'm chasing a 542 code with erratic shifting, but steady speedometer sweep.
I suppose this would be suitable on my 94?
1994 FORD F-150 Parts - WWW.HORIZONPARTSGUY.COM
Thank you for the info
I suppose this would be suitable on my 94?
Ok 1995.
Put jack stands under the rear axle.
There should not be a plug under the dash for this system other than the plug for the RABS module.
The plug should be at the drivers hood henge just aft of the EEC Self-Test plug.
Put a A/C volt meter on this plug, it only has two wires.
Run the truck up to 30 MPH.
Does the voltage increase smoothly and continuously from 0 to approximately 3.5 volts AC as vehicle speed increases from 0 to 48 km/h (0 to 30 mph) at the plug? Topped out at 1.5
If not unplug the RABS module and see if you get it now. Topped out at 2.5
If not unplug the PSOM also, do you get the VAC now? Will tackle that bear tomorrow.
If not change out the VSS sensor at the rear end. Looking at listings below
If the wiring is OK and you still do not get the voltage reading then you may have a bad tone ring or bearings in the rear end.
Put jack stands under the rear axle.
There should not be a plug under the dash for this system other than the plug for the RABS module.
The plug should be at the drivers hood henge just aft of the EEC Self-Test plug.
Put a A/C volt meter on this plug, it only has two wires.
Run the truck up to 30 MPH.
Does the voltage increase smoothly and continuously from 0 to approximately 3.5 volts AC as vehicle speed increases from 0 to 48 km/h (0 to 30 mph) at the plug? Topped out at 1.5
If not unplug the RABS module and see if you get it now. Topped out at 2.5
If not unplug the PSOM also, do you get the VAC now? Will tackle that bear tomorrow.
If not change out the VSS sensor at the rear end. Looking at listings below
If the wiring is OK and you still do not get the voltage reading then you may have a bad tone ring or bearings in the rear end.
Thank you for the info
Fleet Owner
Joined: Aug 2005
Posts: 23,666
Likes: 301
From: Easton,Ks
542 code usually means that you have a bad fuel pump in one of the tanks or you have tested the fuel circuit by jumping pin#6 to pin #2 of the EEC self-test DLC plug.
Yes what you listed above does also apply to a 1994.
I take it the code above is from a KOEO electrical test only and to see if you have a VSS problem you need to be patient and let the test go on to the CM code read out.
The VSS will not show up on KOEO electrical test only.
Yes what you listed above does also apply to a 1994.
I take it the code above is from a KOEO electrical test only and to see if you have a VSS problem you need to be patient and let the test go on to the CM code read out.
The VSS will not show up on KOEO electrical test only.