KEY FOB imobiliser problems please help!!

[Highonlife]

Hi all,

First post so don't shoot me down

Need to sort this ongoing problem with my explorer.

Everytime we go to a shopping are near us, when we come back to the explorer the key fob will not open the doors and will not take the imobilser off to start it.
This is now the third time its happened and each time we had to get the recovery truck back, then it works fine.

Why it this happening?? how can we stop this??
please help. I am typing this while I wait for my other half to be recovered again from the shopping area!!
its driving us mad

 

[jp450]

See the following post:

http://www.explorerforum.com/forums/showthread.php?t=154492

 

[Highonlife]

thanks for the link and hi

 

[gijoecam]

First, do you have the factory Ford anti-theft system, or an aftermarket alarm system installed? When the vehicle won't start, does the 'Theft' light on the instrument panel flash rapidly? Does the engine crank but not fire? Does it do anything at all? What, exactly, does it do when it won't work?

-Joe

 

[jp450]

I would guess, Highonlife correct me if I am wrong, that the "Theft" light goes on solid when the key is turned to the start possition.

 

[Highonlife]

First, do you have the factory Ford anti-theft system, or an aftermarket alarm system installed? When the vehicle won't start, does the 'Theft' light on the instrument panel flash rapidly? Does the engine crank but not fire? Does it do anything at all? What, exactly, does it do when it won't work?

-Joe

Factory anti-theft one. When I get stuck in the bad area, doors will not open from key fob, light just pulses slow and not the fast one. turn key and nothing, no crank. Then when I have it recovered and moved the light will flash about 3 times then works fine, plus lock and open ok.

cheers for any help.

 

[Highonlife]

I would guess, Highonlife correct me if I am wrong, that the "Theft" light goes on solid when the key is turned to the start possition.

when its good, put key in has solid light, press fob and light flashes fast 3 times, then goes off and engine starts and light goes off.

 

[gijoecam]

What year, model, and engine?

The fact that it doesn't crank leads me to believe that it's not the PATS causing the problem. If it was the PATS not recognizing the key, it would crank but not fire. The PATS sends the signal to the PCM, but the starter cranking is handled strictly by the ignition switch, starter solenoid, and starter motor.

How comfortable are you troubleshooting the system using a multimeter?

-Joe

 

[Highonlife]

What year, model, and engine?

The fact that it doesn't crank leads me to believe that it's not the PATS causing the problem. If it was the PATS not recognizing the key, it would crank but not fire. The PATS sends the signal to the PCM, but the starter cranking is handled strictly by the ignition switch, starter solenoid, and starter motor.

How comfortable are you troubleshooting the system using a multimeter?

-Joe

97 4.0 v6 auto

Crank when?? when its going ok or when the explorer has the fault??

cranks when good and just clicks nothing when bad.

Troubleshooting errr ...i'll have a go if I can give a complete idiots guide.

cheers for any help joe

Any quick tips to get of being recovered and being able to start the explorer when non start is the bad areas??

 

[gijoecam]

97 4.0 v6 auto

Crank when?? when its going ok or when the explorer has the fault??

cranks when good and just clicks nothing when bad.

OK, being a 97, the starting system is wired a bit different than the 98... The anti-theft system on a 97 can actually cause the starter to not crank. I never realized that... learn something new every day!!



a few more questions...

When it's NOT working, you cannot open the door with the remote, correct?

Does the keypad on the door work? If so, does entering the code unlock the doors?

When you stick the key in the door and unlock it, does the alarm sound?

When it's NOT working, you stick the key in the ignition, turn it on, then turn it to the start position and nothing happens, correct?

When it's NOT working, and you try to start the engine, what is the THEFT light on the dash doing?

Troubleshooting errr ...i'll have a go if I can give a complete idiots guide.

cheers for any help joe

Any quick tips to get of being recovered and being able to start the explorer when non start is the bad areas??

We can get around to the troubleshooting in a bit... A little background info first.

In your 97, the RAP module controls a starter interrupt control relay under the dash. Ordinarily, when you turn the key to start the engine, power flows from the fuse box through the ignition switch, then through the starter interrupt relay, and triggers the starter relay on the firewall under the hood.

Now, if the RAP module detects an intrusion, it will not close the starter interrupt relay and, therefore, you will not be able to start the engine using the key. However, in that case, the PCM is unaffected, so it's just waiting for the engine to turn over, and it'll run.

In the 98s, they changed the system so that the output from the RAP module sends a signal to the PCM, preventing the PCM from firing the engine. That difference is what allows you to do what I'm going to suggest if you're in a bind.

First, purchase a cheap screwdriver and leave it in the glove box. The next time it acts up, you should be able to turn the ignition switch on, pop the hood, and jumper the starter solenoid with a screwdriver to crank the engine. It *should* fire and run just fine. To do that, locate the starter relay on the driver's side fender well, to the right side of the power distribution box. It will be about 60CM round, with two large battery cables on it and one small wire. One side connects to the battery, the other side connects to the starter. To jump the solenoid, you'll remove the small trigger wire (should be a push-on elbow connector) and use the screwdriver to carefully jump the battery side to the small post where the small wire was connected. That should trigger the starter and, if the ignition is switched on, it should start and run.

Now, as for the root cause of the problem, that's a lot tougher to diagnose. To do so, you almost need to catch it in the act, and have someone hook up a diagnostic scanner right there on the spot. By viewing the PIDs for the system, a technician should be able to determine whether or not the system is sending the correct output to the anti-theft relay.

If I was troubleshooting it, I would pull the starter interrupt relay from the relay module under the dash and check for power coming in from the RAP module. The relay is normally closed, so the only way it could be stuck open is if the RAP module is sending the signal. I suppose it's possible that the relay is sticking, but the odds of that happening in the same location repeatedly are pretty slim. Worst case, you could just bypass the relay itself with a jumper wire in place of the relay. That would permanently prevent the relay from failing, but would also defeat the starter interrupt from the RAP module.

Hope that wasn't all too overwhelming... Good luck! Let me know if I can help any more!

-Joe

 

[Highonlife]

OK, being a 97, the starting system is wired a bit different than the 98... The anti-theft system on a 97 can actually cause the starter to not crank. I never realized that... learn something new every day!!



a few more questions...

When it's NOT working, you cannot open the door with the remote, correct?

Does the keypad on the door work? If so, does entering the code unlock the doors?

When you stick the key in the door and unlock it, does the alarm sound?

When it's NOT working, you stick the key in the ignition, turn it on, then turn it to the start position and nothing happens, correct?

When it's NOT working, and you try to start the engine, what is the THEFT light on the dash doing?


-Joe

Cannot open door with remote when its NOT working.

Keypad on door?? sorry don't know what you mean. told you i'm need idiots guide

key in ignition, try to turn on and NOTHING happens, When it's NOT working

The THEFT light on the dash just pulses if I remember right, dose not go off and dose not flash rapid. Just pulses as if armed.

Will read the idiots guide over and over to get it into my head

Cheers for any help

 

[gijoecam]

Just noticed a type-o in my last post... the solenoid is roughly 60MM in diameter, not 60cm... dang metric anyways LOL!

Also, when I mentioned "driver's side" for the solenoid, I meant that with respect to here in the states. I guess it would be your passenger side LOL!

The keypad on the door was an option on that model. Not all Explorers came with it. (Yours obviously didn't)

I'm assuming that the key in the door works just fine (i.e. it doesn't set the alarm off when you open it with the key). Since the theft light isn't blinking rapidly or on steady when you try to start it, I'm pretty sure it's a problem with either the starter interrupt relay sticking, or a problem with the starter solenoid itself. It's also very possible that the connection of the trigger wire with the solenoid is loose or corroded. Some contact cleaner, a wire brush, and some dielectric grease (all of which can be had for about $5 US at any auto parts store) can ensure that it's not a bad connection at the solenoid.

Here's something else to try: The next time it does it, before you try jumping the solenoid, pop the hood, have your significant other hold the key in the START position, and try wiggling the small trigger wire on the starter solenoid. If it's a bad connection, wiggling the wire will often make the connection and it should crank. If it doesn't crank, pull the wire off and check it (either with a multimeter or a test light) for power when it's in the start position.



On a side note, when your wife visits the place where it doesn't work, is she there all day, or just for an hour? Does it more often fail when the weather is damp or rainy? I'm not ruling out the possibility of the RAP module failing, but I don't know of an easy way to check its output without a diagnostic monitor. I suppose that if you could remove the left rear inside plastic trim panel to access the wiring (no small job in itself) you could check the output of the RAP module to the relay with a multimeter. Barring that, checking it at the relay (or bypassing it) may be your best shot. It's not uncommon to have an area where the remote key fobs don't work. Electromagnetic interference is a tricky thing to diagnose, but should not stop the vehicle from starting manually with a key even in the worst conditions.

-Joe

 

[Highonlife]

Just noticed a type-o in my last post... the solenoid is roughly 60MM in diameter, not 60cm... dang metric anyways LOL!

Also, when I mentioned "driver's side" for the solenoid, I meant that with respect to here in the states. I guess it would be your passenger side LOL!

The keypad on the door was an option on that model. Not all Explorers came with it. (Yours obviously didn't)

I'm assuming that the key in the door works just fine (i.e. it doesn't set the alarm off when you open it with the key). Since the theft light isn't blinking rapidly or on steady when you try to start it, I'm pretty sure it's a problem with either the starter interrupt relay sticking, or a problem with the starter solenoid itself. It's also very possible that the connection of the trigger wire with the solenoid is loose or corroded. Some contact cleaner, a wire brush, and some dielectric grease (all of which can be had for about $5 US at any auto parts store) can ensure that it's not a bad connection at the solenoid.

Here's something else to try: The next time it does it, before you try jumping the solenoid, pop the hood, have your significant other hold the key in the START position, and try wiggling the small trigger wire on the starter solenoid. If it's a bad connection, wiggling the wire will often make the connection and it should crank. If it doesn't crank, pull the wire off and check it (either with a multimeter or a test light) for power when it's in the start position.



On a side note, when your wife visits the place where it doesn't work, is she there all day, or just for an hour? Does it more often fail when the weather is damp or rainy? I'm not ruling out the possibility of the RAP module failing, but I don't know of an easy way to check its output without a diagnostic monitor. I suppose that if you could remove the left rear inside plastic trim panel to access the wiring (no small job in itself) you could check the output of the RAP module to the relay with a multimeter. Barring that, checking it at the relay (or bypassing it) may be your best shot. It's not uncommon to have an area where the remote key fobs don't work. Electromagnetic interference is a tricky thing to diagnose, but should not stop the vehicle from starting manually with a key even in the worst conditions.

-Joe

would not of missed it at 60cm

rhd. No keypad then

if you say its the relay sticking, or a problem with the starter solenoid itself.
Why is it ok all the time everywhere apart from that bad area??

when we vist the area, it can be good or bad weather and will fail instant, left for five mins or hours.

 

[gijoecam]

would not of missed it at 60cm

rhd. No keypad then

if you say its the relay sticking, or a problem with the starter solenoid itself.
Why is it ok all the time everywhere apart from that bad area??

when we vist the area, it can be good or bad weather and will fail instant, left for five mins or hours.

Indeed, that is very odd.... Just thinking, it could certainly be an EMF interference issue preventing the key fob from opening the doors. However, if the alarm doesn't go off when you unlock the door with the key and open it, it means that the RAP module successfully read the chip in the key and disarmed the system. That tells me that the system is at least able to read the key code from the doors at least.

What I'm not sure about is where in the process the RAP sends the signal to lock out the starter circuit. I don't know if it switches the relay when you disarm the system, or only once you turn the key to the start position. All the schematic shows me is that the relay is normally closed, which means that if you unplug the RAP module or cut power to it, the engine should crank.

OH!! Had another idea!! When it won't start, if we can cut the power to the RAP module, that should kill the power to the relay, and allow the starter to crank! Hang on... checking schematics now...

Unfortunately I doubt that'll work... by the looks of it, Fuse #3 under the hood (20A maxi) also powers the fuel pump relay, and if it'll crank, it won't run. Also, fuse #20 in the interior panel (7.5A mini) is switched, and also feeds the radio, a portion of the GEM, the mobile telephone transciever, and the power antenna if so-equipped. Scratch that plan...

As a last resort, you *may* be able to reach up inside the jack access panel and, if you're limber enough, unplug the RAP module from the wiring. The plug is on the top away from the opening, so it may be tough to do, but that might work. In fact, you could try it out without it needing to be stuck in the first place: Unplug it in your driveway and see if the truck will start. I'm theorizing that it should.

-Joe

 

[jp450]

Have you looked under the dash for a small button? Deponding what mood the instaler was in they may have just let it dangle, like mine, or may have installed it to a bracket or somthing.

 

[gijoecam]

Have you looked under the dash for a small button? Deponding what mood the instaler was in they may have just let it dangle, like mine, or may have installed it to a bracket or somthing.

It's a factory alarm. Confirmed in post 6. Did you read the thread?

 

[jp450]

It's a factory alarm. Confirmed in post 6. Did you read the thread?

Sorry I must have missed it.