I hope this is in the right place,

I have been searching this sight and love the knowledge and information I have received from everyone so thanks to all. A little background, I purchased this truck a little over a month ago. It is a 1999 Ford Ranger Extended Cab, 4x4 Manual trans with the 3.0 FFV. I replaced the camshaft synchronizer and cleaned my MAF and IAC. Two days after this my speedometer became erratic fluctuating up and down and the ABS light came on and off intermittently. I replaced the VSS in the rear differential. Everything appeared to be working and then the same issue of the speedometer and ABS came back it is intermittent after warming up.

I ran the FORSCAN and check my fuses. I received the following codes;
CAN Error: 3 (3.7%)
PATS B1681, B2139 PCM P0503, GEM C1752, P1846, P1850, P1866, P1838, B1352, B1318
I also checked all the fuses utilizing a circuit tester and the in cab fuse 33 15 Amp Headlamps, DRL Module, Instrument appears to have no power.

Unfortunately I know just enough to get in trouble when it comes to wrenching and now have no idea where to start.

Any advice would be greatly appreciated.

 

Welcome to the forum

Its good to post the codes, but also good to post the definitions you are using for those codes, lol, also NO ONE has them all memorized
P0503 Vehicle Speed Sensor Intermittent/Erratic/High

What did the old VSS look like?
Did the end thats inside the differential look undamaged?
It shouldn't come into contact with anything inside, it "reads" a tone wheel that spins when axles are moving

If it looked OK then you have a wiring issue, most likely
VSS generates its own AC Voltage, so no power goes TO this sensor
But only the + half of the AC voltage is used
So unplug the sensor and test each of its wires with OHM meter to ground, only one should show as a ground
When you find out which one is + then test it but move the wiring around to see if it shorts to ground

The PATS codes could be from a low battery on startup, test battery voltage after vehicle sits overnight. 12.3volt is minimum, under that means new battery is needed
New battery will be 12.8v
3 year battery 12.5v
5/6 year old 12.3v and time to shop for battery sales

The transfer case codes, P1846, P1850, P1866, P1838, codes could have come from turning key on when transfer case motor was unplugged from harness, did that ever happen
And does 4WD work now?

B1352 Ignition Key-In Circuit Failure
When key is in the ignition a wire on the cylinder gets Grounded, this is not a required sensor, it is there to activate a Chime if drivers door is opened when key is off but still in the ignition switch, its a reminder chime to not leave key in the vehicle when exiting

B1318 Battery Voltage Low
See above, i.e. the PATS issue

C1752 VSS input shorting to ground
Also see above to see if you can find the issue

Do you have rear ABS or 4 wheel ABS, 1999 had 4WABS as an option?
In either case I would unplug the connector on ABS module to see if there is any corrosion inside that could short out the rear ABS sensor(VSS)

 

Thank you for the response and information I will look into these issues and post ASAP.I did notice that I think my VSS may be the wrong one.The tabs that connect to the wiring harness are keeping the harness from locking.I was able to pull apart without manipulating the tabs.I think it may not be seating properly.

What did the old VSS look like? It actually appeared in good shape, Gear oil is really thick and I definitely need to change, had some metal shavings but wasn’t too bad.


Did the end thats inside the differential look undamaged? It appeared undamaged.


It shouldn't come into contact with anything inside, it "reads" a tone wheel that spins when axles are moving

If it looked OK then you have a wiring issue, most likely
VSS generates its own AC Voltage, so no power goes TO this sensor
But only the + half of the AC voltage is used
So unplug the sensor and test each of its wires with OHM meter to ground, only one should show as a ground
When you find out which one is + then test it but move the wiring around to see if it shorts to ground

The PATS codes could be from a low battery on startup, test battery voltage after vehicle sits overnight. 12.3volt is minimum, under that means new battery is needed
New battery will be 12.8v
3 year battery 12.5v
5/6 year old 12.3v and time to shop for battery sales Battery is over 5 years old and voltage was around 12.28 v so will replace.

The transfer case codes, P1846, P1850, P1866, P1838, codes could have come from turning key on when transfer case motor was unplugged from harness, did that ever happen
And does 4WD work now? I had an issue with 4WD when I used a car wash 4WD lights went crazy flashing on and off and 4WD system wouldn’t engage, it seems to have corrected and appears to be working fine now but that was a few weeks ago.

B1352 Ignition Key-In Circuit Failure
When key is in the ignition a wire on the cylinder gets Grounded, this is not a required sensor, it is there to activate a Chime if drivers door is opened when key is off but still in the ignition switch, its a reminder chime to not leave key in the vehicle when exiting

B1318 Battery Voltage Low
See above, i.e. the PATS issue

C1752 VSS input shorting to ground
Also see above to see if you can find the issue

Do you have rear ABS or 4 wheel ABS, 1999 had 4WABS as an option?
In either case I would unplug the connector on ABS module to see if there is any corrosion inside that could short out the rear ABS sensor(VSS) Will check I have 4WABS

 

You most likely got water inside the shift motor connector under vehicle, which is odd, it should be sealed fairly well, disconnect the shift motor connector and have a look inside for corrosion

When the Key is ON the GEM(4x4 controller) monitors shift motors position, if it "doesn't see" that position at anytime key is on the 4WD lights will flash

See if you can trace the shift motor wires back to where they go into the cab, the VSS wires may be part of that harness and thru cab connector, which may be the issue for both
In 2000 and 2001 there was a 40 pin connector that connected wires from under the cab to the in cab harness, known issue for water intrusion shorts
But never read about that for 1999 models
This connector was under drivers seat, came up thru the floor

 

Update on issues and thank you RonD for the assist.

It appears I either had a faulty VSS from the auto parts store or I fried it by connecting it without disconnecting the battery first. Anyway, replaced the VSS with a new one and replaced the battery heavy corrosion on the terminals so gave them a thorough cleaning. No signs of corrosion on any other parts.

With the new VSS and new battery all issues have been resolved. For good measure changed all the fluids.

Thank you again.

 

Good stuff

Thanks for the update