Speedo Issues

Hi All,

So my 95 bronco 351w A.T. is starting to show the gremlins and was wondering if anyone has found a end-all be-all solution to eliminate all the ***** ford electronic crap (PSOM, ECU, etc.) that seem to just go bad for no reason.

I want to keep the 351w for now (because of emissions, runs good n'stong too) but hate that I have to worry that one day it'll be "found on road dead" because of the stupid speedometer capacitors - when I can use freakin GPS instead.

Anyway just weighing options at this point - still my DD.

Thanks

Yo tjg8675,

The capacitors are often the issue the EEC IV module, aka, computer is replaced. But some have successfully replaced the caps as seed press did here at http://broncozone.com/topic/20788-fuel-delivery-problem/

PSOM failures often caused by the 4WABS Control Module when it's 4 microprocessors fail, as they did in our 96. I jumpered out the module's harness connector to get the E4OD to shift correctly and the PSOM to stop doing the wiggle-jiggly. BTW, two yard control module were also bad. Now we run it without,4WABS, just like the good old days.

There are E4OD transmission controllers, but I never bothered reading about them and those folks who were about to install them never came back to give the result.

Hi miesk5,

Thanks for replying.

I am aware of the cap issues in the EEC IV, there is also a power conditioning cap in the PSOM speedo module I've heard once it goes bad all kinds of issues pop up (possibly caused by 4WABS control gone bad).

I currently have wavy speedo above 30mph, abs issues and possibly tranny shift issues.

I have disconnected the abs fuse so abs wont work, that stopped the abs from engaging all the time but obviously no functioning abs.

Trannys shifts in 3&4 are very mushy. 30k on rebuild.

I have only seen trans controllers for diesel /emoticons/[email protected] 2x" width="20" height="20" />

I would prefer at this point to start replacing everything instead of hunting down tiny mysterious problems

My new rule is if the stupid system relies on something like a 3rd brake light bulb to work properly (i.e. torque converter/3rd brake lights issue) it is poorly designed and should be replaced if possible)

the list is growing

PSOM -

Transmission controller

EEC IV/PCM

4WABS Control

ICM

Trying to figure out basic data flow

VSS to 4WABS to PSOM to Trans Contr. to EECIV?

Yo tjg8675,

Here ya go:

The locations of the connectors along the path from VSS to 4WABS and up to Instr Cluster & PSOM are;



To help identify the connectors:

C404 VSS On rear axle sensor (A7) Terminals: 02

to

C205 Male and Female Pins 10 &!16 @ LH rear of engine compartment, in safety wall (Fire Wall) Terminals: 24 In-Line

to

C202 F & M Pins 46 z& 47 @ LH rear of engine compartment, in safety wall (A8) Terminal: 7 In-Line

to

C119 Pins 21 & 22 @ LH front corner of engine compartment on 4WABS control module (E10),Terminals: 40; through module

& out:

O/LB to C202 F & M pin 58 @ LH rear of engine compartment, in safety wall (A8) Terminal: 7 In-Line to C252 PSOM Pin 4

LG/Y to Splice S107 Engine control sensor harness, from C119 near T/O to G101 (G101 RH side of Radiator support); & to C202 pin 69 to PSOM Pin 5

C252 is for Programmable Speedometer/Odometer Module (PSOM), Behind top LH side of I/P, on PSOM (A7) Terminal: 12 Color: B

C202 F and M and spliced to Ground G100 (BK)

G100 & G104 (tied together in diagram) G100 @ LH front of engine compartment, on upper radiator support

G100 Serves Component:

Fuel Pump Module

Inertia Fuel Shutoff

Misfire Sensor aka crankshaft position sensor

Misfire Sensor Shield

Output Shaft Speed (OSS) Sensor

Powertrain Control Module (PCM), 5.0L

G200 Behind bottom of RH cowl panel

Serves Component:

Air Bag Diagnostic Monitor

Electronic Shift Control Module

Instrument Cluster

Programmable Speedometer/Odometer Module (PSOM)

Remote/Keyless Entry Module

Speed Control Servo/Amplifier Assembly

From PSOM C252 Pin 7 (GY/BK) to Splice S231 Main harness, near T/O to speed control amplifier to C202 pin 21 to Splice 246 to PCM pin 3 and to Speed Control Servo Amplifier Connector C216 pin 3.

...

C185 PK/O @ PCM 96 Bronco 5.0L Powertrain Control Module (PCM) LH side of safety wall, on powertrain control module (PCM) (C10) Terminal: 104 Color: GY

C185, 96 Bronco 5.8L Powertrain Control Module (PCM) LH side of safety wall, on powertrain control module (PCM) (C10) Terminal: 104 Color: GY

C185 @PCM to C202 F and M

Splice 216 to Ground G200, Instrument Cluster ground is inside passenger side kick panel

and on to C185 @ PCM PIN 58 (GY/BK) and from Pin 46 to MLPS (TR) Pin 2

I am using a tablet without split screen, can you compare the diagram at top to my narrative?

I originally did this for my 96, so your 95 may have some differences in connectors, splices and pin numbers.

Hi Meisk5,

thank you for your reply, unfortunately wiring has never been my thing, I can solder with the best of em but schematics and diagrams are not my strong suit.

So may take me time to figure that all out.

I do know that my 95 5.8l vin H seems to have to have the wiring of a 94, as haynes manual shows 2 O2 sensors for 95 but mine only has 1

Thanks again

I think I have the vss-to-pcm-schmatic figured out...bear with me

I will check splices, pin#'s and connectors to match my 95 today

I know I do not have an overhead console, not sure what role that plays with the VSS? kidding of course

So it seems repair shops are getting fewer and far between these days for a psom repair

can anyone recommend a place that still will repair those?

Yo,

The VSS does provide a signal to the overhead console.

EDIT... note that in our 92 through 96 Broncos; the rear axle mounted VSS provides a signal via the 4WABS module to PSOM that converts this signal to 8,000 pulses per mile. That signal is sent out to the PCM and then to:

E4OD,

speed control amplifier;

and overhead consoles compass/outside temperature display module, if equipped.

If the thermometer sensor (mounted behind the front bumper/grille) data indicates a higher temperature, the module uses a high-speed counter to monitor vehicle speed to determine whether engine heat is causing erroneous readings. The counter is incremented when the speed is greater than 53 km/h (33 mph) and decremented when the speed is between 16 and 53 km/h (10-33 mph). If the speed is less than 16 km/h (10 mph), the counter is reset, and the displayed temperature is not updated from its last reading. If the counter is greater than two minutes, the currently sensed temperature is displayed. If the high-speed counter has counted less than two minutes, the temperature can increase only one degree per minute.

&

If the signal from the PSOM is distorted the E4OD will be negatively affected.

OK on checking my vss flow to your 95. As far as the PCM pin numbers, I think I used my 96 obd 2 PCM pin diagram that is different from your 95 EEC iv PCM.

I will need a 95 wiring diagram to show psom to eec iv pins.

Will look for one tomorrow.

Hang in there!

Yo, just saw your psom repair Q.

I can personally vouch for http://dnaspeedometers.com

Great Customer Service!

I won't mention the $ they charged to ck out my original PSOM.... but it was LESS than driving to the UPS store... ABSOLUTELY NOTHING!

They tested it over a period of about 3 days and called me with the good news. Then they shipped it back immediately.

Hi miesk5,

My 95 seems different than commonly shown 95 wiring, it seems to have 94 emissions wiring - single O2 sensor

leftover from 94? who knows

I do have aftermarket exhaust, maybe previous owner changed this, when he changed the exhaust.

Where is 2nd O2 usually located?

thank you for the psom place

1995 Bronco Vin H Chassis Electrical System

I was wrong about the 2 o2 sensor 95/94 issue, book lists 95 vin H on two separate pages, mustve been tired of reading and glanced that sry

Yo,

OK. Thanks for the update.

Found good write-up explaining ford VSS/DSS systems from a transmission publication, was curious how the 4wABS routing differs from RwABS routing? (see attachment - figure3)

Will be tracing wires today or tomorrow to verify if miesk5's above information matches my 95 5.8l, not sure how far I can get without taking apart (I do not want to remove PCM, or 4wABS module unless I have to, just yet)

starting from

R-VSS (orDSS) to ABS Control module to PSOM to PCM

FL-VSS to ABS Control Module to PSOM to PCM

FR-VSS to ABS Control Module to PSOM to PCM

Sorry if I'm starting from the basics, we all gotta start somewhere right?

Do any other models share same 4wABS control module?

Yo,

On the article, that is correct. I did have the Ford 92 though 96 Bronco and F Series Workshop Manuals and 94 through 96 PCED/EVTMs, so that is how I was able to compile such as that connector flow from VSS to 4WABS MODULE TO PSOM TO EEC, E40D, & Cruise Control.



F Series and 87 to 92 Broncos have RABS; 93 TO 96 Broncos have 4WABS, as Built.

F47A-2C219-FA is Ford PN for 94 to 96 Broncos and I BELIEVE: 93 to 94 Explorers.

Stop by your Ford dealer parts dept. They can look it up using dealerships Interchange Guide and Buyer's Guide.

Ford has these on line at http://www.fordparts.com

But as usual the on-line customer data base is screwed-up.

Thank you miesk5,

I appreciate your help a lot, I just wasn't sure how much things changed from 95 to 96, I know there was a big change from OBD1 to OBD2

Just gave it a wash... not sure if I posted any pics here of the new shoes I got for Christmas last year