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Topic Review (Newest First)
04-06-2012 09:16 PM
Kevbz
Quote:
Originally Posted by JkF1018 View Post
The problem is solved......it turned out to be a bad PCM, changed it and started right up. Bought new PCM from Rockauto.com, good place for parts.Thanks to the entire sight for all the information. Thanks especially goes to Kevbz, without the diagrams you sent I would of just swapped parts. Rubi and Sherpa thank you for the help also.
04-06-2012 06:46 PM
JkF1018 The problem is solved......it turned out to be a bad PCM, changed it and started right up. Bought new PCM from Rockauto.com, good place for parts.Thanks to the entire sight for all the information. Thanks especially goes to Kevbz, without the diagrams you sent I would of just swapped parts. Rubi and Sherpa thank you for the help also.
03-31-2012 09:12 PM
Kevbz Sorry it ended up being that, but hope it works out
03-31-2012 09:05 PM
JkF1018 Spent the afternoon shooting wires with a friend and we determined that the PCM is bad (hope we are correct). Kevbz, thanks again for all the tech data you provided.
03-29-2012 09:12 PM
JkF1018 Update, today I changed the Camshaft position sensor and still not running. I then pulled a sparkplug and check for spark and no spark. I hooked up the scanner again and it won't even read the Jeep, reports an ERROR. I'm leaning towards a bad PCM. I called the dealer and for $112 buck they can check it out and tell me what's wrong.
Scratching my head in Florida.
03-29-2012 03:31 PM
Kevbz Curious how you are making out?
03-27-2012 09:00 PM
RUBI 4 MY MRS Did you get full voltage at fuse 11? The reason the fuel pump only pumps for about 3 seconds if the engine doesn’t start is because the ASD relay shuts it down (through the PCM). That tells me that MAYBE the PCM only grounds the ASD when the key is on for 3 seconds.(?) Jumping the relay should allow the pump to continue to pump. You can check the pump pressure. Now see if you get spark & power to the injectors. The PCM pulses the injectors through the ground circuit.
03-27-2012 07:40 PM
Kevbz Have you checked for good spark?
03-27-2012 07:31 PM
JkF1018 RUBI, We did try jumping the ASD relay and it didn't start, so I will be searching for the part that might be the problem. I changed the Crankshaft Position sensor (no difference) and now learning about the Camshaft Position sensor to see if that's it.

Thanks for the help, I will keep you posted!
Jim
03-27-2012 06:29 PM
RUBI 4 MY MRS If you jump B1 & B2 (30 & 87) of the ASD relay, will it start? That would be a good place to start. If that works then sort out why the ASD is not grounding at the PCM. There are several parameters that the PCM monitors which could be shutting the ASD down.
03-27-2012 06:06 PM
JkF1018 KevbZ, Thanks for the additional download, I will study it tonight. Today, I hooked up my scan tool to my jeep and it wouldn't connect to the jeep (electrically), I got an error. I then checked for a ground at the Auto Shutdown Relay (key on) and nothing. I did read 12 VDC on one side but no ground, guess that's why it's not working. Wondering if my PCM is bad? Any idea how to verify the operation of the PCM?
Thanks again for the help.

Jim
03-26-2012 09:40 PM
Kevbz
Quote:
Originally Posted by JkF1018 View Post
Kevbz
Wow, I downloaded the file opened it up and fell out of the chair. This is going to help a bunch.

I owe you a beer! (or 2), Thank you
for some reason my 1997 TJ file is really a 2003 FSM. and I cant get another copy that's correct. that file will help with the basics but some specifics will be wrong. the closest I can find is a 1998.

if you want, delete the one you downloaded and download this one. its not 97 but as close as one could hope, not to much changed between those years.

https://docs.google.com/open?id=0B7_...c0pwbHg2ZWxlQQ

we'll make it one beer since i screwed up!
03-26-2012 09:19 PM
JkF1018 Kevbz
Wow, I downloaded the file opened it up and fell out of the chair. This is going to help a bunch.

I owe you a beer! (or 2), Thank you
03-26-2012 08:52 PM
JkF1018 Thank-you for all the documentation, and thanks for all the help. I plan on jumping back in the troubleshoot mode after work tomorrow.

I'll provide an update tomorrow night. Thanks again
03-26-2012 03:13 PM
Kevbz hummm...It was supposed to be the 1997 FSM....but your right, its not. I thought it was my fault (i tried to organize all my wrangler files the other day and thought I might of mislabeled it) but I checked my download site and that's the one they have for the 1997.

Sorry about that...it would have some info that is not applicable to the 1997. I cant find the 1997, the closest I have is a 1999 FSM. You'll have to use the Morris site link. I was trying to get you something you could download and have.
03-26-2012 11:51 AM
RUBI 4 MY MRS
Quote:
Originally Posted by Kevbz View Post
here is the complete Factory service manual also...I made it downloadable from my google docs...you might be able to find something in there also

https://docs.google.com/open?id=0B7_...Ri1oS2NRQ2ZHUQ

I think that one is for a 2003 so there may be some differences.
03-26-2012 12:39 AM
Sherpa
Quote:
Originally Posted by RUBI 4 MY MRS View Post
Check voltage at fuse 11 in the fuse block behind the glove box.
Not only this, but check the fuse itself (and the others while you're there).

Back when I installed an electric radiator fan in my former TJ, I tapped an unused relay outlet in my PDC for the power lines. During the install, I somehow shorted one wire. Unbeknown to me, this caused one of my glovebox fuses to blow (I forget which one), and that in turn disabled the fuel pump relay. When I next went to start the Jeep, it cranked endlessly but wouldn't fire.

I don't know what made me thing to check the fuses, but when I did I found that one was blown. Once I replaced it, the Jeep fired right up as usual.
03-25-2012 10:55 PM
Kevbz here is the complete Factory service manual also...I made it downloadable from my google docs...you might be able to find something in there also

https://docs.google.com/open?id=0B7_...Ri1oS2NRQ2ZHUQ
03-25-2012 10:35 PM
RUBI 4 MY MRS Check voltage at fuse 11 in the fuse block behind the glove box. If less than battery voltage check ignition switch. That powers most if not all relays in the PDC. As to the fuel pump, the relay only stays energized for about 3 seconds if the engine doesn’t start. The PCM blocks the ground to the relay after that. Then there is the ASD relay that may need to be jumped as well.

The wire from the ignition switch that feeds #11 fuse is dark blue (DB). That is the one that is hot in both the “on” & “start” positions.

If you need help with complete wiring diagrams (more than linked above) go here Jeep Knowledge Base
03-25-2012 08:11 PM
JkF1018 Kevbz, I have not checked the center wire to the coil, but will after work. I changed the crankshaft position sensor and problem didn't go away, so I put the original back in. I will look into the camshaft position sensor next. As for swapping the relays we swapped them every way possible. I have measured battery voltage 12.8 VDC (or something close to this voltage) at the PDC with the key off, same measurement as read from the battery posts. When the key is on the fuel pump relay should energize and it doesn't. we pulled the relay and measure voltage (key on) and it is 11.2 VDC. How much voltage does it take to evergize the relay? We pulled the relay and jumped it to make the fuel pump come on. I did the gauge test that you spoke about and the gauges tested fine. The fuel gauge went to full then to a half and on to "E" where it stayed. The jeep is acting like there is a cutout safety switch that needs to be rest. Thanks for the help. This is now a challange.

Jim
03-25-2012 04:06 PM
Kevbz with the key off I metered my power dist center and had no voltage drop at the starter relay. my batter was 12.83 V on the posts, and 12.83 V across the relays posts also.

that voltage drop has me stumped
03-25-2012 04:04 PM
Kevbz just for giggles did you check the center wire on your rotor to the coil?

i am going back to basics...air/fuel/spark theroy, you have fuel, I am assuming air (unless something major happened to intake, which is a long shot) you have crank, so cylinders are moving by nature of the flywheel. I know you can get a spark plug tester to test for actual spark at the plugs.

there is a camshaft position sensor also...

try this also, with the key off hold your odometer button down and hold it ( the button on the cluster to switch from odometer to trip meter) then turn the key to on (not starting, just acc on position) then release the trip meter button...the guages should cycle through a self test...not sure if this truly test the ECU, but i believe it checks for signals

also there is a "automatic shutdown relay" in the power dist center...have you swapped out relays with something non essential to see if the a relay is shot..

just throwing out ideas here for you
03-25-2012 03:44 PM
Kevbz I remember seeing a fuseable link somewhere in the system. If even the new batteries are held at 11.2 volts...there's some resistance there somewhere.

Lemme think on it for a sec...
03-25-2012 03:26 PM
JkF1018 Kevbz, Thanks for responding and "double" thanks for the wiring diagrams.

This is where I am at, Put 2 different batteries in the jeep and they did not fix the problem. What we have is 12 volts getting into the PDC but only 11.2 VDC getting to the relays with the key on. I changed the CPS and still nothing. Replaced the + battery terminal cleaned as many grounds as I could find. Jumped the Fuel Pump relay again and shows good pressure on the gauge. The fuel quantity gauge has not move off "E" since this problem started, wonder why. Have plenty of gas (only 176 miles on this tank) and gas is present at the rail. We are now suspecting the PCM has gone bad but do not know how to verify it, and it is expensive. I am at 2 days of TS and have not found the "smoking gun". Any other advise would be greatful
Fustrated in Florida
03-25-2012 10:50 AM
Kevbz i just re-read you first post and saw it WAS cranking. CPS is the meanest of all sensors. ask any heavy duty F-250/350/450 owner, lol..those power strokes eat them like candy. If cheap enough I'd go after replacing that.
03-25-2012 08:48 AM
Kevbz
Quote:
Originally Posted by JkF1018 View Post
Troubleshot the electrical system to the PDC relays (all) and discovered none are energizing when the key is in the on position. Checked all the fuses and checked each relay using a meter and the battery, all good.

So you were not reading the 11.2 volts here at all on the fuses? read below about the relays and there energy state.

Is that voltage to low?

Yep, but you should still have domelights, radio, etc. just not enough to crank


Cleaned the grounds, battery terminals still have the problem. What would cause the relays on the PDC too not energize with 11.2 VDC?

That's not likely, the power distribution center should be seeing 11.2 also, there is a big post on the back of it, with three or four wires going to it, you should read 11.2 (or what ever your voltage is) there. a relay by nature will not have voltage present across certian contacts (meaning an a/c relay wont show any voltage until the a/c switch is on, a horn relay wont show any voltage until the horn is pressed) there is usually a switch, either user controlled, activated by temp, pressure or vacuum that powers the relay first. You should see voltage across contacts 87 and 30

We are thinking that the ignition switch,

do you have radio, power points have power? if so your key is working

or as I have read on this sight, the Crankshaft Position sensor is the culprit. Does anyone have any suggestions?

it should just crank in this situation, but never fire
I answered your questions in red up above.

First thing...battery...11.2 is low and can easily keep a starter from turning over. I'd replace it. The only thing is...what killed it? if you cant find voltage at the PDC at all...then i'd lean toward that PDC's ground. They pull a common ground and if that is loose then you wouldn't see any voltage at all, if you were pulling that weak voltage then i say battery only was the problem. But not finding any voltage at all means there is a break in the circuit...and usually the ground is the culprit.

I attached a wiring diagram for your jeep... don't worry that is says its for a SE, the wiring is the same.


I would change the battery...easy stuff first...and see what happens, if no go use the diagram to find the ground wire for the power distribution center and check that.


good luck!
03-24-2012 11:50 PM
2002TJ Your battery is dead.

A fuly charged battery should read at or above 12.8 VDC

At or below 11.5 VDC, your battery is considered dead/discharged.
03-24-2012 11:46 PM
I-Want-A-Jeep Pull your battery and hav it checked for a dead cell. Most I've seen run at 12.3/4 normally and 14.something while running.
03-24-2012 09:26 PM
JkF1018
Power Distribution Center relays not energizing

I am new to the jeep world and having issues. Drove to the store, came out and my 1997 Jeep TJ, (manual 6.0) cranks but will not start, had to call a tow truck to get home. Troubleshot the electrical system to the PDC relays (all) and discovered none are energizing when the key is in the on position. Checked all the fuses and checked each relay using a meter and the battery, all good. Pulled the Fuel Pump relay and jumped the system to make sure the fuel pump is good and it is. Checked voltage at the Fuel Pump relay and it reads 11.2 VDC with the key on. Is that voltage to low? Cleaned the grounds, battery terminals still have the problem. What would cause the relays on the PDC too not energize with 11.2 VDC? We are thinking that the ignition switch, or as I have read on this sight, the Crankshaft Position sensor is the culprit. Does anyone have any suggestions?

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