Speedometer Problem

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Mar 18, 2006 | 08:09 PM

gateway1

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From: Middleburg

Speedometer Problem

The speedometer on my 95 Bronco skipps and does not read the speed that I am going. I inspected the Speed Sensor Ring and replace the fluid in the diff. I did not notice any damage to the ring. Thinking that the problem is the Speed Sensor itself, I replaced it. The problem stll exsist. My ABS light stays on as well. Can some one plaese help me out with this before I shoot my truck...

Mar 18, 2006 | 09:37 PM

Streetgang

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From: Hoboken, NJ...

AS for the ABS light....cant you just check the ABS codes through the ABS test port right next to the ECU test port mounted on the LS fire-wall. The two issues may or may not be associated with each other. If you had another PSOM to put in real fast to check that one against your would be cool also.

Mar 18, 2006 | 11:07 PM

gateway1

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From: Middleburg

Totaly Stumped

The only ABS test harnes I found in my truck was a red one in the engine compartment. I looked every place that the Haynes manual said that there was a test harnes but could not find one.

I tried to run the test with the test harnes I foud. The ABS light blinked twice. I looked it up and there is no code for blinking twice.

I am totaly stumped......

Last edited by gateway1; Mar 18, 2006 at 11:35 PM.

Mar 19, 2006 | 10:37 AM

greystreak92

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From: Gateway to the West

Ok, let me clear one thing up about the VSS issue. If the VSS was indeed the problem and you have an automatic in your truck, you would be having strange shift operations from the tranny in addition to the other symptoms. The VSS in the rear differential provides speed information not only to the PSOM but also the ECA and the ABS computer. The PSOM uses the info to calculate speedometer output readings. The ECA uses the info to tell how fast the truck is moving and the E4OD when to shift. The ABS computer uses the info to determine the actual speed of rotation of the rear axle and compares it against the engine/tranny speed to deterime whether the rear wheels are slipping or not. If your truck has a manual transmission the shift symptom is a moot point.

If the ABS computer doles out fault codes similarly to the EEC computer then two blinks would indicate a "system pass" which is no faults (nothing wrong). I am not certain this is the case though.

Last edited by greystreak92; Mar 19, 2006 at 10:40 AM.

Mar 19, 2006 | 12:23 PM

gateway1

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From: Middleburg

I do have an automatic trany. Thanks for the input.

Do you think I could have aproblem witht the ACU?

Mar 31, 2006 | 08:45 PM

rudedogii

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From: USA

I had a simular problem. First have the computer scanned and checked for codes.
Next if nothing is found take the truck to a Speedo Shop thease guys found my problem right a away.