2005 Gateway module

WWDiesel · **Posted:** Sun Jul 28, 2019 3:16 pm

geordi wrote:

Have you chased the grounds? The power could be finding ground through another circuit (the AC compressor is a popular option) and it might be intermittent b/c of that.
The primary ground points are behind the driver's headlamp and under the engine fuse box, on the fender adjacent to the box, and on the firewall near the ECM.

Checking all the grounds is certainly worthwhile. A floating ground can cause all kinds of strange happenings.

Pictures of the grounds geordi referenced:

biggfisch · **Posted:** Sat Aug 03, 2019 12:59 pm

My understanding is that if the SKIM is the issue, it will let it start for 3 seconds, then stall. Mine won't even crank that initial time. It does act like the second time you try to start it, after a SKIM code, where it doesn't even try to spin over. Interestingly enough, when I can pull a code in the no-crank state, it throws a P0513 (incorrect immobilizer key) code. But when it starts, no codes are thrown. Strange behavior, indeed. Maybe the WCM is going bad, but I would think the dealer would have been able to pick that up if it is having issues.

I've checked the ground behind the headlight, and under the battery tray. Took them off, cleaned the rings and mounting surface, and reseated everything. Will need to check the other two nearby grounds.

I did manage to find a used FCM at a full service salvage yard. I wound up looking looking up a turbo on car-part.com, and calling the salvage yards that looked like they still had a whole Jeep. The hard part is getting the guy that answers the phone to get off his duff and go look for the module in the yard, since it doesn't show up in their computer system. Had to make 5 or 6 calls before I found someone that would play ball, and was willing to ship. Should be able to complete sourcing next week.

Sir Sam · **Posted:** Sat Aug 03, 2019 2:41 pm

biggfisch wrote:

My understanding is that if the SKIM is the issue, it will let it start for 3 seconds, then stall. Mine won't even crank that initial time. It does act like the second time you try to start it, after a SKIM code, where it doesn't even try to spin over. Interestingly enough, when I can pull a code in the no-crank state, it throws a P0513 (incorrect immobilizer key) code. But when it starts, no codes are thrown. Strange behavior, indeed. Maybe the WCM is going bad, but I would think the dealer would have been able to pick that up if it is having issues.

I've checked the ground behind the headlight, and under the battery tray. Took them off, cleaned the rings and mounting surface, and reseated everything. Will need to check the other two nearby grounds.

I did manage to find a used FCM at a full service salvage yard. I wound up looking looking up a turbo on car-part.com, and calling the salvage yards that looked like they still had a whole Jeep. The hard part is getting the guy that answers the phone to get off his duff and go look for the module in the yard, since it doesn't show up in their computer system. Had to make 5 or 6 calls before I found someone that would play ball, and was willing to ship. Should be able to complete sourcing next week.

Ya what you are describing sounds like it could also be a bad skim. Try the used FCM but if that fails to correct it you might need to look at the skim.

How you went about it is the right way, find yards with a 2005 CRD, and then call them asking about the module. What did you end up paying for it?

Billybob · **Posted:** Sat Aug 03, 2019 2:56 pm

The cranking of the engine is very straight forward action...nothing to do with the FCM.

Turning the ignition key to the final position ie. "start" supplies +12 volts to the coil of the Starter Relay.
If the other side of this relay coil goes down to ground due to either the Neutral or Park interlocks supplying it then +12 volts feeds through to the starter solenoid...if fuse #8 40 amps has not blown!

So if the engine does not crank then it could be the ignition switch, actuator pin assembly, bad starter relay, blown fuse #8, bad connections to the starter/solenoid, bad grounding straps between the engine block and chassis or bad battery connections including the negative battery lead to chassis.

So removing the Starter Relay and briefly jumping female pins 30 to 87 inside the empty socket will send +12 volts to the starter solenoid if fuse #8 is OK!
This jumping of pins 30 to 87 bypasses the ignition switch, Park and Neutral Interlocks and Actuator Pin Assembly.

So under the above condition the +12 volts should be present at the starter solenoid and if the solenoid is wired firmly and is in good condition the solenoid should supply +12 volts to the starter motor.
An intermittent non-cranking could also be that the starter motor has stopped on a bad commutator segment or the brushes are worn or dirty.
The engine actually firing would be subject to many other conditions and the FCM does play a part in this!

A SKIM problem does not stop the engine turning over...if the SKIM LED is flashing the engine will turn over and fire but will cut out after a few seconds. If the SKIM LED is on solid then the engine will crank but not fire at all. :wink:

TKB4 · **Posted:** Sat Aug 03, 2019 3:46 pm

Note too that GDE said they can turn off the skim in the ecm

geordi · **Posted:** Sun Aug 04, 2019 12:18 am

Billybob wrote:

The cranking of the engine is very straight forward action...nothing to do with the FCM.

Turning the ignition key to the final position ie. "start" supplies +12 volts to the coil of the Starter Relay.
If the other side of this relay coil goes down to ground due to either the Neutral or Park interlocks supplying it then +12 volts feeds through to the starter solenoid...if fuse #8 40 amps has not blown!

So if the engine does not crank then it could be the ignition switch, actuator pin assembly, bad starter relay, blown fuse #8, bad connections to the starter/solenoid, bad grounding straps between the engine block and chassis or bad battery connections including the negative battery lead to chassis.

So removing the Starter Relay and briefly jumping female pins 30 to 87 inside the empty socket will send +12 volts to the starter solenoid if fuse #8 is OK!
This jumping of pins 30 to 87 bypasses the ignition switch, Park and Neutral Interlocks and Actuator Pin Assembly.

So under the above condition the +12 volts should be present at the starter solenoid and if the solenoid is wired firmly and is in good condition the solenoid should supply +12 volts to the starter motor.
An intermittent non-cranking could also be that the starter motor has stopped on a bad commutator segment or the brushes are worn or dirty.
The engine actually firing would be subject to many other conditions and the FCM does play a part in this!

A SKIM problem does not stop the engine turning over...if the SKIM LED is flashing the engine will turn over and fire but will cut out after a few seconds. If the SKIM LED is on solid then the engine will crank but not fire at all. :wink:

This is NOT correct at all. The keyswitch has ZERO direct connection to the starter motor, it is completing a circuit to the COMPUTER and basically asking "I'd like to start, may I?" and the computer will engage the starter relay IF all of the sensors have checked out during the power-on-self-test and there are no emergency-stop codes in the computer. The computer WILL NOT allow the starter to engage if the airbags have been deployed for example. Not for a 3-second start, not for a few revolutions of the starter... NOT AT ALL. The most you might get is one "bump" of the starter and then the computer will cut you off entirely. I know b/c I have personally experienced this with a computer from a wreck that had the bags blown and had no obvious E-stop codes stored.

Sir Sam · **Posted:** Sun Aug 04, 2019 7:01 pm

Yup I agree with Geordi, the ECU controls the starter relay, the key does not. The ECU can lockout the starter relay.

biggfisch · **Posted:** Sun Aug 04, 2019 7:41 pm

That would make sense. The airbag module doesn't appear to communicate with the ECM directly, looks like it uses the PCI bus to talk to everything. If the FCM is kaput, the ECM might not allow the starter to engage, since it doesn't "hear" anything from the airbag module. Not saying that's exactly why mine won't crank, but it makes sense to me. One of my co-workers was a tech for Mercedes for 10 years, and says this kind of system is pretty common on the German cars of this era, with the FCM (gateway) module parsing the data from the individual modules and passing it to the ECM. Said they were a real bear to troubleshoot, if you didn't know what to look for. He did mention that it was pretty rare for one to die completely, though.

FCM from the scrapyard in Dallas is $300 shipped. Feel a bit like I'm taking it in the shorts for a used module, but at this point, I'm just ready to get this all behind me and the CRuD back on the road. I suppose the new module and dealer fees would have been $400+, so I guess I can't be too mad.

geordi · **Posted:** Sun Aug 04, 2019 9:27 pm

I've entirely struck out trying to locate a module for you - so considering that you either get the $300 module or enjoy a 4300-lb lawn ornament... Doesn't look like you have much of a choice. The more recent part-outs have all been 2006, unfortunately.

flash7210 · **Posted:** Sun Aug 04, 2019 9:29 pm

Due to a wiring fault that I have not been able to fix, I have pulled the fuses and disabled the air bag system.
My Jeep starts and drives just fine.

A air bag deployment should not completely disable a vehicle.
There have been many instances where a light impact or faulty sensor has caused a air bag deployment and the driver was still able to safely operate the vehicle.

Billybob · **Posted:** Mon Aug 05, 2019 6:29 am

Sir Sam wrote:

Yup I agree with Geordi, the ECU controls the starter relay, the key does not. The ECU can lockout the starter relay.

OK my bad....if the Park or Neutral Interlocks are faulty then the ECM will not supply ground to the Starter relay. Likewise an airbag problem may stop the Starter Relay from energizing.

But jumping out pins 30 and 87 of the Starter Relay will override the ignition switch, the actuator pin assembly, the Starter Relay and the Park and Neutral interlocks.
The engine will turn over, if Fuse #8 40 A is OK, but will not fire if the ECM has an issue.

I should have been clearer in my post...was merely trying to see if the engine itself was able to turn over...replying to biggfich's post of not cranking sometimes! Jumping out the Starter Relay could thus expose one of the items listed above...ignition switch for example....as a possible problem :oops:

biggfisch · **Posted:** Mon Aug 05, 2019 10:02 pm

The Jeep won't crank at all when it is in its state, which seems to only occur when its either at operating temp with a real good heat soak of the engine compartment, or its really really hot out. It's been well in the 90's in OK for the last couple of months, so the Jeep has sat either at the dealer or my driveway until I can get it figured out. I jumped the starter relay, and it cranks fine when I do so, but it won't fire, so something is killing the fuel as well. Maybe the SKIM as previously suggested, maybe Stripe and the rest of the gremlins have posted up in my Jeep... I dunno.

I tried it tonight with the ASD relay jumped, and then jumped the starter relay. Still just cranked and cranked with no fire. I figure the ASD relay is good, since it clicks when I plug it in with the key on, but thought it was worth a few skeeter bites to try it jumped anyway. No dice. I also tried disconnecting the battery for a bit, to try resetting any SKIM codes. Still nothing. Suppose I'll just have to wait for the module to come in the mail.

Anyone heard if 1945GPW has had any luck finding an FCM?

geordi · **Posted:** Mon Aug 05, 2019 10:07 pm

biggfisch wrote:

The Jeep won't crank at all when it is in its state, which seems to only occur when its either at operating temp with a real good heat soak of the engine compartment, or its really really hot out. It's been well in the 90's in OK for the last couple of months, so the Jeep has sat either at the dealer or my driveway until I can get it figured out. I jumped the starter relay, and it cranks fine when I do so, but it won't fire, so something is killing the fuel as well. Maybe the SKIM as previously suggested, maybe Stripe and the rest of the gremlins have posted up in my Jeep... I dunno.

I tried it tonight with the ASD relay jumped, and then jumped the starter relay. Still just cranked and cranked with no fire. I figure the ASD relay is good, since it clicks when I plug it in with the key on, but thought it was worth a few skeeter bites to try it jumped anyway. No dice. I also tried disconnecting the battery for a bit, to try resetting any SKIM codes. Still nothing. Suppose I'll just have to wait for the module to come in the mail.

Anyone heard if 1945GPW has had any luck finding an FCM?

Wait... Will it fire when cold but not when hot? That's the classic indication of the crankshaft sensor being out! The computer MUST see a camshaft pulse within 2 pulses of the crankshaft, but it NEEDS the crankshaft sensor to reply in order to start counting and know where it is in the cycle or it will never inject fuel.

biggfisch · **Posted:** Mon Aug 05, 2019 10:45 pm

Would a faulty CKS prevent the ECM from allowing the starter to crank the engine? Its been on the list since it's about the right age to go bad, but checked out OK when I pulled it. I'm pretty sure the engine cranked fine when I had the CKS pulled out and everything was cool, just didn't start. Can't remember for sure since its been a few months and 12-packs since then.

WWDiesel · **Posted:** Mon Aug 05, 2019 11:27 pm

biggfisch wrote:

Would a faulty CKS prevent the ECM from allowing the starter to crank the engine? Its been on the list since it's about the right age to go bad, but checked out OK when I pulled it. I'm pretty sure the engine cranked fine when I had the CKS pulled out and everything was cool, just didn't start. Can't remember for sure since its been a few months and 12-packs since then.

No, even with a bad CPS, the starter will still spin the engine over but just will not start.

Billybob · **Posted:** Tue Aug 06, 2019 2:15 am

Not firing when hot definitely points to the crank sensor.

If you suspect a SKIM problem first confirm that the red LED on left of cluster is not burnt out.
Hold the Odometer Reset Plunger in while turning ignition ON.
The LEDs will all light up and the gauges will move around.....this way you can be sure that the SKIM LED is operational.

A skim problem would show itself as follows:

If the ECM is not happy with the SKIM code sent to it by the SKIM module at the top of the steering column...the Red LED will flash. Motor will fire and run for a few seconds then cut out.

If the ECM is happy with the SKIM code it will energize the ASD relay and motor will fire up.
However the ECM at this stage makes a check that the ASD relay has in fact energized....if the ECM does not receive the feedback from the ASD relay that it....the relay.....has energized then the Red LED stays fully lit. The engine will turn over but not fire at all.

I had this second problem on my old KJ whereby the engine would crank but never fire. The early KJs do not have a Red Led but a "key" icon with a line through it and this was ON solid.
I jumpered out the ASD relay contacts and could then start and drive the Jeep until I had a chance to locate a broken wire going to the coil of the ASD relay. This is not a method of Hot-wiring the Jeep as the ECM has other means of stopping the Jeep from firing!

So unless you have flashing SKIM LED or a solid SKIM LED On it is doubtful that there is a SKIM issue! :wink:

1945GPW · **Joined:** Mon May 05, 2014 8:37 pm **Posts:** 27

Biggfisch, Waiting for a FCM as well. Hopefully get it soon. Thanks for asking. I had the same issues you had with the wrecking yards. They plug the part number for the FCM and the ECU comes up. Oh well. Hopefully this ordeal will soon be past us.

TKB4 · **Posted:** Wed Aug 07, 2019 8:28 am

I have an 05 FCM on my salvage jeep but I am planning to put another motor in it eventually. If there was a way to let you use it until you find your own or to confirm thats all the problem with yours.I would consider it kinda like Sasquatch etc rents timing kits. I would definitely not sell it right now.

GordnadoCRD · **Posted:** Wed Aug 07, 2019 6:00 pm

RE: Crankshaft Position Sensor. (CKP sensor)

biggfisch wrote:

Would a faulty CKP prevent the ECM from allowing the starter to crank the engine? Its been on the list since it's about the right age to go bad, but checked out OK when I pulled it. I'm pretty sure the engine cranked fine when I had the CKP pulled out and everything was cool, just didn't start. Can't remember for sure since its been a few months and 12-packs since then.

When my CKP failed, it would not crank at all. The fail point was about one notch from full operating temp. When going goofy, it would die when driving at that point, and not start until cooled off. OR if it managed to reach full operating temperature, it would run great until turned off for 15 minutes or so, then stay dead until cooled off.

This thing is worth carrying a spare around.
Sometimes triggers a code - sometimes not
Sometimes triggers when hot, sometimes when just off cold, sometimes anywhere in between.
Sometimes cranks - no start
Sometimes no crank at all.
Always seems to come and go with thermal change, but specifics can vary substantially.

GordnadoCRD · **Posted:** Wed Aug 07, 2019 6:09 pm

WWDiesel wrote:

biggfisch wrote:

Would a faulty CKS prevent the ECM from allowing the starter to crank the engine? Its been on the list since it's about the right age to go bad, but checked out OK when I pulled it. I'm pretty sure the engine cranked fine when I had the CKS pulled out and everything was cool, just didn't start. Can't remember for sure since its been a few months and 12-packs since then.

No, even with a bad CPS, the starter will still spin the engine over but just will not start.

Sometimes it will, sometimes it won't, WW. Yours did, so did Papaindigo's Mine never did, but the single component change (CKPsensor) Fixed it with no other changes and no problems since.

2005 Gateway module

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