Speed sensor solved dead ABS, speedo and tranny sift problem

[hoghappy]

My ABS light has been on a long long time (5 years) and then my speedo started acting up this past winter(intermittantly not moving) while the tranny would shift in and out of neutral and shift hard...took it to the shop and they fixed the speedo and tranny by replacing the rear end speed sensor and said they could not get the ABS to work...a mess of codes and it would cost too much to start replacing sensors. So I drove it home 1/2 mile away, parked it and then started it back up the next day to move it in the driveway and it fixed itself. The ABS light is out and the brakes are working right again.

Is it possible the computer needed time to reset after replacing the sensor?

I'm just happy the tranny is not having to be replaced. 220+k miles and no smoke and not a drop of anything leaks anywhere....original motor, tranny and drive train even the water pump is still original...amazing. Did replace radiator recently and fuel tank, pump etc after she quit running this winter and I found rust in the tank. They sure were proud of that Motorcraft fuel pump... :angry:

 

[Rons beast]

Thanks for the info HH.

Yes is is entirely possible that the computer had to "learn" new sensor inputs, and had to be recycled, or rebooted, to make the new information priority. It's common in my Mercedes, to have to recycle the comp. even after an oilchange and servce reset. It's simple as turning the vehicle off for a few seconds and restarting.

Glad it is working for you.

Thanks again.

 

[miesk5]

yo

As Ron advised,

Adaptive Strategy Relearn Procedure: After repairs have been made and the KAM cleared drive the vehicle for at least ten miles to allow the PCM to relearn the values for optimum performance. Note: During the ten mile relearn drive, the vehicle may exhibit some driveability symptoms. These should be eliminated when the KAM has relearned the operating values. Keep Alive Memory (KAM) within the processor must always have voltage supplied to it. This voltage is supplied by the Keep Alive Power (KAPWR) circuit (Pin 1) that connects directly to the battery. KAM contains adaptive parameter tables that allow the processor to adapt to different operating requirements. It also contains the Continuous Memory codes. Continuous Memory codes will be erased any time KAPWR is disconnected (i.e. battery disconnected, processor disconnected, breakout box installed, open in the wire, etc.). If KAM fails within the processor, all Continuous codes will also be erased.

Ford went cheap on the ckt to save $; they ran the VSS signal through the 4WABS Module and back to to PSOM (speedometer & odomoter) instead of having a parraell path directly to PSOM and another path direct to PCM and to E4OD

btw, Here is the ckt showing flow from VSS sensor to its Connector, C404,

AND,

to C205, C202, In Engine Bay at Firewall to Dash Harness

http://www.supermotors.net/registry/media/170517_1

C202 & C205 Pin-Out Diagrams w/Component Identification; (Engine Bay at Firewall to Dash Harness); "...C202 & C205 are directly forward of the steering column support bracket (the BIG Aluminum casting) beside the brake pedal..."

Source: by Steve83 (Steve, That dirty old truck) at SuperMotors.net

Steve also shows the C205 & C202 Connectors in the harness (Removed from Bronco)

at

http://www.supermotors.net/registry/media/907910

and to and thru 4WABS & it's Connector C119,

C119 4WABS Control Module

to PSOM thru it's C252

and to PCM C185

C185 EEC (PCM) Location in Engine Bay Diagram in a 94

Source: by Kenny B (Ken B, Kenny's 94) at SuperMotors.net