Ecm trouble | Ford Explorer Forums - Serious Explorations

  • Register Today It's free!

Ecm trouble

np24

New Member
Joined
July 26, 2008
Messages
7
Reaction score
0
City, State
Shelton, Ct
Year, Model & Trim Level
'87 Ranger, 4x4 SuperCab
I have a 97 Ranger with a 4.0l. It was originally an auto and I swapped in the manual with the correct ecm.
What would cause an ecm to not read the 3 oxygen sensors and the speed sensor?
I am having this problem with both ecms, auto and manual.
I'm getting oxygen sensor activity at the ecm connector. I checked with a meter.
The speedometer works and the gem won't shift to low range unless the truck is almost stopped.
There is no abs light on and it works correctly.
The only code that comes up is p0401 because the egr valve isn't hooked up. Its a 93 manifold with no provision for it.
The front O2s are brand new.
Could the rear O2 be shorted and disabling everything?
Thanks
 



Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!
.





I disconnected the rear o2 sensor hoping that it was the problem. The check engine light came on saying that the heater and sensor circuits were open or shorted.
I'm glad that it's reading it, but it still doesn't explain why the scan tool can't see any activity.
I've tried a brand new action and my bluetooth elm scanner. They work just fine on my car and my dads truck, just not on my ranger.
Did ford do something weird with the sensor data for this year that makes it unreadable by scanners?
 






I would swap the auto engine harness with the manual harness. I would also swap the auto trans harness for the manual trans harness.

The pin outs on the ECM, & harnesses can be different, and you might have faulted circuits. You can move the pins (in each connector) to make complete circuits, if you study up on the wiring diagrams, but that can be a serious PITA.
 






As far as I can tell, the pinout is the same for both ecms besides the transmission wiring.
I removed the unneeded wiring from the transmission harness. It was the wires that actually connected to the transmission. I left all of the others alone.
I was using a ford evtm for the diagrams.

I jumpered the wires for the neutral switch together so the t-case would shift.
I also never installed the clutch pedal switch.
I don't know if either of those would cause this problem .
 












Back
Top