Wacked-out check engine light

rdsrds123 · May 26, 2018

My ck engine light comes on and the speedometer drops to zero and the temp gauge dies and the tire pressure monitoring system comes on and intermittantly starts flashing--all at the same time. The engine will run fine, but once I turn it off it will not restart. The tires need no air. I took it to Advanced Auto to ck the code, and they said the port was dead, that maybe a fuse for that is bad. I'll ck that out. What could problem this be? It happened last week, too, and then it sat for one hour and when the tow truck showed up it started! It passed emissions inspection three days ago. It has happened like this several times. Sometimes the truck will restart when I turn it off, and other times, like this time, it doesn't restart.

RonD · May 26, 2018

What engine size in the 2007 Ranger?

So the CEL comes on BEFORE the speedometer or temp gauge drops?

2007 has a digital dash, only analog gauges are oil pressure and fuel level, and they stay working?

It stays running with CEL on, but after turning it off and then turning on the key does the CEL come on, indicating computer is starting/booting up?
Or is the CEL off when trying to restart, so computer is not booting up?
That would explain the OBD2 no connection, but so would blown fuse

rdsrds123 · May 26, 2018

The speedo dropping temp gauge falling to C and ck engine light coming on all happen simultainously. Plus the tire pressure monitor comes on and flashes! No oil guage. 4cylinder five speed. It will run fine indefinately. But when I turn it off it will not restart. Its like that now
Might start in the morning. Ck light is on when I try and restart.

ericbphoto · May 26, 2018

A blown fuse is not normally an intermittent problem - normally. Could still be a fuse problem. But I wouldn't bet on it. Really sounds like a loose connection somewhere. Loose plug, loose ground connection, broken wire, or bad solder joint on a circuit board. Make sure the harness is firmly plugged into the computer. Maybe even check to make sure water hasn't gotten into that connection, although they are normally very well sealed. Make sure all fuses are properly seated. Look for harness connections that may not be fully plugged into each other. Any place you see a ground connection, make sure there isn't paint between the wire lugs and the metal they are being connected to and make sure they are connected tight.

Sent from my SM-G960U using Tapatalk

rdsrds123 · May 26, 2018

Thanks! In the morning

rdsrds123 · May 27, 2018

Still wont start. I'm thinking that the issue is not emissions or engine function related. If something happened that causes the speedo to drop to zero ( coolant gauge drops to C and ck light comes on)yet still allow the vehicle to run indefinately until it is turned off, the problem is serious but not engine related. I mean if oil pressure dropped the engine would be toast. If something emissions related failed it would pollute the enviornment more but would not be serious enough to make the driver stop NOW. I would guess a personal safety issue like an airbag malfunction or some such. Liability issue for Ford? Actually I think it none of these. Havent gone out to wiggle wires. I'll do that later. I think trying to fix this is a waste. The symptoms dont add up normally.

rdsrds123 · May 27, 2018

There is no fuse listed for the code access port. I think maybe the person at Advanced Auto was wrong( I give him the benefit of the doubt here). The port is good but Im not going to spring for an OBD2 scanner when I think this is bs.Any way to test the port otherwise?

RonD · May 27, 2018

Does the starter motor crank the engine, or does nothing happen when you try to restart?
Any Flashing lights on the dash when trying to restart, i.e. PATS anti-theft light

The Fuel Pump should run for 2 seconds, and 2 seconds only when you turn the key ON, you can hear it run from the cab, not quiet, 2 second HUMMM from the gas tank.
This means computer is booting up correctly.
Turn key on and off as much as needed to confirm fuel pump is coming on, doesn't hurt anything

Computer controls spark and fuel, not starter motor, and if it cranks but doesn't start then its either spark or fuel that's the issue.

You can spray fuel into the intake and see if it starts/fires, that would tell you spark is working but not fuel injectors

The digital dash gets its info from the data bus system in the vehicle, its a data network inside the vehicle, and for some reason that is failing, its part of the Smart Junction Box(SJB) located with the fuse panel in the passenger side kick panel.
These are one piece units for the most part not serviceable.

But you could simply be loosing power at the dash, there are 2 or 3 separate 12v wires and as mean grounds.
There is also the Ignition switch under the steering column, it has as least 3 power outs for different circuits and fuses, if it is going bad then 1 circuit could be loosing power causing dash issue

rdsrds123 · May 27, 2018

Ron, I just went out and checked the items you mentioned. It will not crank. Lots of lights come on when the key is in the crank position. The theft light does flash then. With repeated attempts, I cannot hear the fuel pump. I know what sound you mean.

The oil pressure light came on when I hit a bump a couple of years ago, and it remains on constantly since that time. I have good pressure.

Switches under the dash?

rdsrds123 · May 27, 2018

Ok, SJB. Have to research that. Is the SMJ refer to the whole fuse box on the passenger side? I see a couple of fuses in the box in the engine compartment that refer to SJB.

rdsrds123 · May 27, 2018

https://m.ebay.com/itm/2007-Ford-Ranger-Fuse-Box-Relay-Unit-For-Parts-Only-7L5T14B476AC-Module-30-12K1/113018707122?hash=item1a50709cb2:g:l4EAAOSwG7FaiyX8

Here is a. SJB on ebay. Looks burnt but I understand these cost hundreds. The more I read about them the more it seems like it could be the problem. They can cause combinations of seemingly unrlated electrical issues

rdsrds123 · May 27, 2018

RonD, I've been taking all day digesting what you wrote this morning about the possible caused of this dash problem. That was a comprehensive post. Thanks! I've gone to ebsco and looked over their wiring diagrams. I can't do much about the SJB if it's bad. I don't think I have a fuse problem, and so, maybe not a power problem. I'd like to check out the dash grounds and the power sources there if I can. I need to know where they are located, i9f anyone can tell me. I think I'm looking for grounds G-301, and G-204. Thanks Ron, and thanks all.

RonD · May 27, 2018

Yes, SJB is the whole unit in the passenger kick panel, its also option specific, not cheap to replace

If Theft Light is Flashing with Key ON then PATS(passive anti-theft system) is preventing the restart, or start.
PATS disables starter motor and Fuel pump/injectors if key used in the ignition doesn't Read correctly
Do you have another key to try?

PATS is ONLY used on startup, once engine is running PATS can't/won't shut it off, but would on next start up.

A mobile locksmith with Ford software on a laptop can make and add new PATS keys to the system

PATS should not cause an issue in the dash, but that issue may be causing the PATS issue on restart

Each PATS key has an embedded RFID tag in the handle, it needs no battery, each RFID tag has a unique number
Each vehicle is programmed and shipped with 3 PATS keys at the factory, those 3 numbers are stored in computers memory.
When you turn on the PATS key the RFID Tag is read by computer and the number compared to the 3 on its list, if it matches then starter motor will work and so will fuel pump and injectors, if no Match then Theft Light Flashes and No Start.

You can add PATS keys to the computer yourself, IF(big if)....you have 2 currently working PATS keys for that vehicle, so you can add a 3rd and/or 4th key
If you don't then you need Ford software on a computer and you hook that computer up to the OBD2 port on the vehicle and then add the new PATS key number(s) to its memory

rdsrds123 · May 27, 2018

Tried three different keys. Still no start. I now have a new symptom. Aftering trying to start the truck and the key has been removed from the ignition, the PAT light continues to flash-- four times. Then the dash goes dark

rdsrds123 · May 27, 2018

Could the problem be the chip that recieves the signal from the key?

Wacked-out check engine light

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