Help no crank but good battery, starter...

[Neil Matlock]

I have a 2000 Ford expedition that will not start with turn of the key. My battery is good, my starter is good, and ignition switch is good. I can get the car to start by jumping the starter relay terminals. When I do that I have a check engine light with o/d flashing. There is intermittent power to stereo, washer fluid level light. the check engine codes are for O2 sensor bank one and two sensor two, and trs. When I checked voltage to the transmission range sensor there’s nothing. I have replaced the interior fuse box and gem. The only fuse that doesn’t have power is the OBD2/ lighter which I believe is fuse number three. On the relay there is no power to red/tan wire at any key position. Any help would be really awesome.

My thoughts are leading me to the pcm or bad ground. The factory service Manual I have sucks and any recommendations for one that has a complete wiring schematic would be helpful.

 

[stamp11127]

Welcome to the site. If you have the true OEM manual with wiring diagrams it doesn't "suck". Don't think what may be the problem, diagnose it then prove the part is faulty before condemning it.

Since it only starts with the starter relay jumped that is pointing to a problem with the control circuit for it. Look at the diagram for starting and charging circuits then use a meter to find the problem.

PCM isn't in control of the starting circuit. It only senses the engine running then keeps the fuel pump energized.

If you don't have power on the wire that controls the relay you don't have a ground problem. Check ignition switch, digital range sensor and harness.

How did you determine the ignition switch is "good"?

 

[Neil Matlock]

I do not have an oem diagram. Some of the wire designations are impossible to read (quality wise)

To be honest I initially put a new one in. When the problem didn’t resolve, I put a multimeter on each connection and started on acc, off, on, start. Then recorded the voltages. I put the old one back in and repeated the process, then returned the part. The only wire that fluctuates in voltage is red blue (when in start it has 12 v all other times it was at 4.06 or something close).

I have no voltage to trs pins at trs.