2002 Ford Explorer won't start!!!

[gzimm01]

no crank / starting circuit

I have th Ford EVTM manual for an 03 explorer. What do you need to know?

are there any other circuits/influences attached to the "starting system" circuit that affect voltage to the DTR input voltage red/light blue wire? should I look at something else ? does the battery being disconnected for a long time affect anything in the starting circuit ( ie.. pcm, PATS, etc )?

 

[Pontisteve]

The starting circuit looks pretty basic. Here's the rundown.

Fuse 1.12 (50A) in the battery junction box should be hot at all times. It sends power to the LOAD side of the starter relay. When the relay is energized, that power goes to the starter solenoid.

Fuse 2.29 (Hot in Start) (10A) in the central junction box sends power to the DTR sensor. When in Park or neutral, the DTR sends that power out to the CONTROL side of the starter relay, as a +. The PCM grounds the - side of the CONTROL side of the starter relay.

So you have fuse 2.29 getting power from the ignition switch somewhere, when you are in "start" position. That power goes into the DTR, and if it's in park or neutral, power comes out of the DTR and to the starter relay.

Since you're asking about DTR input voltage, let me look at just that for a minute...

Ok, fuse 2.29 is used for both the DTR sensor input, and also to power up fuse 2.28 (5A), which is circuit 1003, which is the audio unit (radio). I suppose if the radio was pulling this circuit to ground, you could have a problem... but that should just pop that 5A fuse if that were the case.

Fuse 2.29 gets its power from circuit 50, which is position 3 (start) at the ignition switch. That would be a 14 gauge red wire (pin 7 on the ignition switch).

The ignition switch itself gets power from a 12 gauge yellow wire (circuit 37) powered up by fuse F1.23 (30A) (Hot at all times) in the battery junction box.

So to summarize, here's the power flow:

Fuse 1.23 in BJB > pin 4 in Ignition Switch > "START" position > pin 7 in Ignition Switch > Fuse 2.29 in Central Junction Box > DTR sensor > Park or Neutral position > contact #85 on the starter relay (white/pink wire).

 

[Pontisteve]

That's the power supply chain to the starter relay. The PCM is the sole ground to the control side of the starter relay. In this case, it's only going to be PATS that might hold you up. But PATS doesn't interrupt the starter relay. It lets the vehicle start, and then kills it.

I'm not sure offhand what the conditions are for the PCM to ground the starter relay. We can look into that if we need to, but if you aren't getting power to the #85 on the starter relay, we need to backtrack that instead.

In fact, the EVTM doesn't say what the PCM grounding conditions are. You would have to find that in the service manual. I think I have that on .pdf if we need it.

I would say check fuse 2.29 for power on both sides of that fuse when you hit the start position. If you have power there, and not at the DTR sensor, then it's a problem with the wire or the connectors between that fuse and the DTR. There is a connector on the central junction box, a connector on the DTR sensor, and another connector C110 in the middle.

It's possible there is corrosion at C110. That connector is on the engine bulkhead, RH side. That's right above the PCM connector, on the firewall, the middle of 3 connectors, right near the speed control actuator.

 

[gzimm01]

That's the power supply chain to the starter relay. The PCM is the sole ground to the control side of the starter relay. In this case, it's only going to be PATS that might hold you up. But PATS doesn't interrupt the starter relay. It lets the vehicle start, and then kills it.

I'm not sure offhand what the conditions are for the PCM to ground the starter relay. We can look into that if we need to, but if you aren't getting power to the #85 on the starter relay, we need to backtrack that instead.

In fact, the EVTM doesn't say what the PCM grounding conditions are. You would have to find that in the service manual. I think I have that on .pdf if we need it.

I would say check fuse 2.29 for power on both sides of that fuse when you hit the start position. If you have power there, and not at the DTR sensor, then it's a problem with the wire or the connectors between that fuse and the DTR. There is a connector on the central junction box, a connector on the DTR sensor, and another connector C110 in the middle.

It's possible there is corrosion at C110. That connector is on the engine bulkhead, RH side. That's right above the PCM connector, on the firewall, the middle of 3 connectors, right near the speed control actuator.

I think there is a disconnect between 2002 and 2003 fuses. no 2.29 in my 2002 manual for the passenger compartment fuse panel is for "4x4,GEM module, ABS control and Moon roof" which function/fuse are you referencing ? I will check DTR connector and the bulkhead connector ..

 

[Pontisteve]

My 03 lists F2.29 as the power source for the DTR sensor. The 2002's were apparently split years, early and late. Looks like the late might be the same as 03's, so you must have the early build.

 

[Pontisteve]

So the power path is:

F1.23 > Ignition Switch > Start position > F2.4 > DTR Switch > P59 Joint Connector 2 > Starter Relay +.

The rest looks basically the same. F1.12 is where power comes from on the LOAD side of the relay. When the relay clicks on, that power continues to the starter solenoid.

The F1. fuses are battery junction box. The F2. fuses are Central Junction box.

 

[gzimm01]

That's the power supply chain to the starter relay. The PCM is the sole ground to the control side of the starter relay. In this case, it's only going to be PATS that might hold you up. But PATS doesn't interrupt the starter relay. It lets the vehicle start, and then kills it.

I'm not sure offhand what the conditions are for the PCM to ground the starter relay. We can look into that if we need to, but if you aren't getting power to the #85 on the starter relay, we need to backtrack that instead.

In fact, the EVTM doesn't say what the PCM grounding conditions are. You would have to find that in the service manual. I think I have that on .pdf if we need it.

I would say check fuse 2.29 for power on both sides of that fuse when you hit the start position. If you have power there, and not at the DTR sensor, then it's a problem with the wire or the connectors between that fuse and the DTR. There is a connector on the central junction box, a connector on the DTR sensor, and another connector C110 in the middle.

It's possible there is corrosion at C110. That connector is on the engine bulkhead, RH side. That's right above the PCM connector, on the firewall, the middle of 3 connectors, right near the speed control actuator.

your response was perfect, I rechecked input power in the fuse box(good) , and moved to the bulk head connectors ... I found a loose connection on one of the bulk head connectors and reconnected it, it all seems to be working now! . In my original post I mentioned I had removed and repaired the engine, apparently this connector was removed during the repair process. I completely missed it.. (my bad)

Your dialog was spot on and very helpful..! Thank you so much for your insight and guidance.

 

[Pontisteve]

your response was perfect, I rechecked input power in the fuse box(good) , and moved to the bulk head connectors ... I found a loose connection on one of the bulk head connectors and reconnected it, it all seems to be working now! . In my original post I mentioned I had removed and repaired the engine, apparently this connector was removed during the repair process. I completely missed it.. (my bad)

Your dialog was spot on and very helpful..! Thank you so much for your insight and guidance.

I'm glad it worked out for you! I'll tell you this. You can buy used Ford EVTM's (Electrical Vacuum Troubleshooting Manual) on Ebay for your specific year and model so cheap, it's a no brainer to own one. I've bought them anywhere from $10 shipped to $30 shipped. I own every Mustang EVTM just about, because I tune and work on Mustangs for a living. And of course, I bought one for my own 03 Explorer. I also have some Ford (or ripoffs thereof?) Repair manual CD's, which are also dirt cheap, and cover nearly all makes and models over a period of a few years.

It's nice to have the electronic manual, because you can cover so many applications like I did with this 02 Explorer of yours. But nothing beats having the paper manual right in front of you while you're working on troubleshooting wiring. I paid $9.77 shipped for my Explorer EVTM! It's not worth NOT having one for that price.

If you ever want an SCT programmer for your truck, let me know.

 

[drizzle 007]

Same issue here. It was working fine all day, then suddenly won't start. Has plenty of power. Checked the fuel shutoff switch (passenger side kick panel) and starter/ignition relay (spot 12 in the under-hood fuse box), it was fine.

I don't want to replace the starter if that's not the issue.

Anyone???

crank shaft sensor!!

 

[410Fortune]

8 year old thread!!!