Head scratcher

[ryeder]

I just had a check engine light come on in my 96 and pulled a P0500 code. So, I swapped out the speed sensor on the diff. The check engine light was gone...but...
I now have a blinking overdrive light, no speedometer and a beeping that indicates an issue with the airbag system. I'm not sure if they are all related or coincidence. I've checked connectors and fuses. All seem ok. I've read where there's a second speed sensor in the tranny but have yet to locate it. Guess I need some direction on finding the problems. Thanks in advance.

 

[Tiha]

I would say the new speed sensor is bad.

If you put the old speed sensor back in do you get your speedo back?

Otherwise broken wire maybe?


Not aware of any speed sensors in the E4OD. Rather I should say, there is no speed sensors in the E4OD

 

[ryeder]

Maybe that's why I couldn't find it on the trans...lol. and I don't have the old one to test. Guess it'll be another road trip to town. Thanks for the heads up.

 

[Tiha]

There is a way to put a meter on it and test it, but I have never done it, just plug and play.

Kind of weird the speedo doesn't bounce or do anything but swapping the sensor out is my first try. Just keep your recipet they can credit the faulty one back.

Too bad they cover any of the hassle of having to get and install the faulty part.

 

[ryeder]

I think that if they covered the hassle part, they'd go broke.

 

[miesk5]

Yo ryeder,
DTC P0500 From Bronco PCED Section 5A
Diagnostic Subroutines
Powertrain Diagnostic Trouble Code (DTC) Charts
Application:
BroncoKey On Engine Off:
Key On Engine Running:
Continuous Memory:
Diagnostic Trouble Code (DTC) P0500 indicates vehicle speed sensor malfunction. Possible causes:
-- Damaged Programmable Speedometer/Odometer Module.
-- Damaged Rear Anti-Lock Brake System, Sensor.
-- Damaged Speed Control Module.
-- Damaged Powertrain Control Module (PCM).
-- Harness open or shorted.
Key off.
Inspect Rear Anti-Lock Brake sensor and electrical connector for being properly seated and installed.
Inspect connector for damage, corrosion, etc.
Inspect wire harness from sensor to the Modules for damage due to chaffing, burnt, corrosion, etc.
Has any problem been found?
Yes
SERVICE as necessary. COMPLETE PCM reset to clear DTCs (REFER to Section 2A, «Powertrain Control Module (PCM) Reset»). VERIFY a symptom no longer exists.
No
GO to DJ2
DJ2 CHECK FOR INTERMITTENT CIRCUIT FAULT
Key off.
Scan Tool connected.
Access VSS PID.
Record VSS data while driving vehicle simulating road shock.
If possible, drive vehicle through a pool of water.
Return to Service Bay and review recorded PID.
Is a blip shown on the recorded graph?
Yes
ISOLATE fault and SERVICE as necessary. COMPLETE PCM reset to clear DTCs (REFER to Section 2A, «Powertrain Control Module (PCM) Reset»). RERUN «Quick Test».

No
GO to DJ3
DJ3 CHECK SIGNAL TO MODULE
Key off.
Disconnect PCM. Inspect for damaged or pushed out pins, corrosion, loose wires, etc. Service as necessary.
Install breakout box, reconnect PCM.
DVOM on the 20 volt AC scale.
Observe voltage between Test Pin 58 and Test Pin 33 at the breakout box while gradually increasing vehicle speed to 50 mph.
Is maximum voltage received greater than 4.0 volts?
Yes
REPLACE PCM. REMOVE breakout box. RECONNECT all components. RERUN «Quick Test».
No
GO to DJ4
DJ4 CHECK CONTINUITY HARNESS
Key off.

Yes	No
REFER to the Instrument Cluster, Speed Control or Brake Group in the Service Manual.​	SERVICE short circuit. REMOVE breakout box. RECONNECT all components. RERUN Quick Test.​

 

[miesk5]

Due to limits imposed on characters here, see the rest of my post at https://www.fullsizebronco.com/thre...leage-failure-hard-shift.521236/#post-7407444

 

[ryeder]

As I was at the beginning stage of creating a to check list to follow, along you came with this one. Many thanks for tomorrow's battle plan.

 

[ryeder]

Finally admitted defeat on the electrical gremlins and took the Bronco to the local Ford dealer. They did find the problem. Broken wire for the VSS. As for the air bag alarm and light issue, I was told that the air bag monitor module was fried but they couldn't repair it due to that part being obsolete. That was the first b/s comment from them. Then he said that the speedo needle bounce might be due to a bad speedo cable or driveshaft sensor. I just looked at him. My reply can't be posted. I paid the bill and left... never to return. Lesson learned. Think I will just stick with my pre-80's builds.

 

[ryeder]

PS...found this out back of the dealer...1979 frame off build. Wasn't for sale.