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Troubleshooting & Technical Questions & ModificationsHave technical or modification questions about the Crossfire?
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I purchased a 2005 limited with one key that wouldnt lock the doors for my step son. So I had rob at NEEDSWINGS reprogram my only working key and cut and program 2 additional keys. I reinstalled the skreem module, antenna ring and ecu and the keys paired flawlessly to the to the vehicle....except now it won't start!
I had zero issues before re installing the skreem, antenna ring and ecu. I put the battery terminals on with the key mistakenly in the on position. I was worried I might have fried the ecu so I tried to connect a code reader to my obd port and the reader now cannot connect to the ecu. I decided to replace the crank and camshaft sensors on a whim...no luck. I checked the rcm solder connections and fuses all good. I checked to see if the rcm was functioning with the key on. Everything functions when I manually close the relays. The 2 relays close when the key is in the start position (verified while the wife tried to start it). I ordered a new rcm incase my current one is somehow faulty.
Any ideas on where I should proceed next? I contacted Rob at NEEDSWINGS to see if he has seen this before. Any help is appreciated!
Hi Jonathan,
I don't think you mentioned if your limited was an automatic or a manual. If it's an automatic, is the gear position indicator in the instrument cluster showing the right gear? (Should be P for park) or a black square? Also, just to be clear, when you measure the voltage across a fuse, that means put the red probe on the contact, and the black probe on a ground point like the negative terminal of the battery. Then move the red probe to the next contact point on the fuse. You should read battery voltage (~12V) on each contact. If you try to read the voltage drop across the fuse, you'll read a very small voltage assuming the fuse is good.
Good Luck,
-Jerry
I reallly think you should go back to my question about the voltage on the fuses of the RCM. I never got from you an exact answer, but fact is: EVERY FUSE ON THE RCM should have power (11 volts or more) on BOTH SIDES of EVERY fuse when the key is ON.
If you don't have that, the car WILL NOT START.
You must measure this voltage with the fuse inserted, you use the little "test pins" on the top of each fuse as I showed in post 20.
I think a wire, somewhere, fractured when you pulled the modules and sent them to Rob. Notice I did NOT say "broke", I said fractured, said wire probably LOOKS fine, but is open under the insulation.
I've seen this before, many times. We know the modules sent in are fine, if this was caused by you pulling things out and putting them back in, then that's my first guess.
You MUST verify power at every RCM fuse as your first step. Once that is verified, I can see chasing grounds or other concerns, but it is human nature to try to turn this into something more complex than it is. We had a car at the Dragon several years ago that would DIE, one of the fuses on the RCM would blow. Change fuse and car would run for some time, then DIE without warning. It all turned out to be a wire that had crept out of it's loom near a sharp piece of metal, it would get hung up and short to ground at certain times. I warned him not to change modules, he didn't, his dad went probing around in the engine compartment and found it some three weeks later.
Tested the new rcm after receiving my ecu back from needs wings....3 fuses power up with the key off and all fuses power up with the key ON
So we know the RCM is OK.
We know the ECU is OK (as per Rob).
Now, if you leave the key "ON" for 45 seconds, does the engine fan warp up to high speed? I can't find where you mentioned a yes/no to that question.
If the fan speeds up, that points to the ECU somehow not getting what it needs. If it does not, that points to what I call "an interlock issue".
That tells us one thing: The Fan Module is powering up,but is not getting anything from the ECU.
This IMPLIES the ECU is not powered up. You previously said a code reader can't talk to the ECU - more evidence the ECU is not powering up.
FRom my study of the manual, the ECU is powered by two wires from the RCM. There are other 12 volt feeds, but the ECU is not powered by them, the ECU only sinks current thru those other leads to activate injectors, plugs or to read sensors. Connector C5 pins 3 and 9 of the ECU are what powers the ECU.
What I would do is verify the ECU has power and to do that, check for power at: ECU Connnector C5 pins 3 (always hot battery voltage) and 9 (12 volts when key is on).
These feeds come from the RCM. Perhaps you damaged the connector at the RCM or the connector at the ECU.
Red arrows show where battery voltage should be present at ALL TIMES. Green arrows show where 12 volts should be when the key is ON. We know the RCM is OK but is it possible a wire pulled loose in the connector at the RCM? Or maybe at the ECU? THis has happened before and you cant SEE it because it happens in the shell of the connector. Based on the fact the RCM and ECU have both been eliminated as causes, I think it may be something this simple.
I swear, this is going to be "stupid and simple" when you find it. The ECU is not powering up. And we KNOW it has something to do with wiring, there is nothing else it can be. And I do agree with the idea of testing grounds to the ECU as well.
ALSO, one thing you can check (this will verify grounds and 12 volt supply) is to look at C3 pins 39, 25, 22 and C4 pins 19, 40. ALL OF THESE must have 5 volts (4.5 to 5.5 volts is OK) on them with the key ON.
If they have nothing, your ECU has no power.
If they have more than 7 volts, you have a missing ground to the ECU.
ONE MORE TIME, all those pins MUST have 5 volts on them, the ECU puts out 5 volts to each of the, they feed sensors and those sensors then send back voltage on other pins, to tell the ECU what is going on . If there is no voltage or TOO MUCH voltage on one more, you found your problem.
I see my photo, try reloading the page. If you are on a phone, get to a real computer.
I swear, this is going to be "stupid and simple" when you find it. The ECU is not powering up. And we KNOW it has something to do with wiring, there is nothing else it can be. And I do agree with the idea of testing grounds to the ECU as well.
ALSO, one thing you can check (this will verify grounds and 12 volt supply) is to look at C3 pins 39, 25, 22 and C4 pins 19, 40. ALL OF THESE must have 5 volts (4.5 to 5.5 volts is OK) on them with the key ON.
If they have nothing, your ECU has no power.
If they have more than 7 volts, you have a missing ground to the ECU.
ONE MORE TIME, all those pins MUST have 5 volts on them, the ECU puts out 5 volts to each of the, they feed sensors and those sensors then send back voltage on other pins, to tell the ECU what is going on . If there is no voltage or TOO MUCH voltage on one more, you found your problem.
I see my photo, try reloading the page. If you are on a phone, get to a real computer.
C3 reads 10+ volts on pins 39 and 25 and ZERO on 22
C3 39 is the oil level sensor, 22 is throttle body... I don't know what 25 is supplying
C4 reads ZERO voltage on pins 19 and 40
c4 19 goes to the accelerator pedal.... i dont know what 40 is supposed to supply
Last edited by Jonathandugan20; Sep 2, 2023 at 02:57 PM.
C3 reads 10+ volts on pins 39 and 25 and ZERO on 22
C3 39 is the oil level sensor, 22 is throttle body... I don't know what 25 is supplying
C4 reads ZERO voltage on pins 19 and 40
c4 19 goes to the accelerator pedal.... i dont know what 40 is supposed to supply
Its in the manual:
C4 pin 40: Fuel tank pressure sensor supply Zero
C4 pin 19: Accelerator pedal sensor supply Zero
C3 pin 22: Throttle body sensor supply (throttle body motor is C1 pins 3/6) Zero
C3 pin 25: MAF/IAT sensor supply 10 volts
C3 Pin 39: Oil level and Map Sensor supply 10 volts
So NONE are correct. I am surprised you have 'highs' on some pins and "lows" on others.
I suspect C5 pins 5, 6 , 7, and 8. Those are the grounds to the ECU. I suspect one or more is open or resistive.
I think you should unplug ALL connectors to the ECU and inspect both male pins and female sockets for damage/bent broken pins.
THen, measure C5 pins 5, 6, 7 and 8 for their resistance to ground. Tie your meter's ground/common lead to the negative battery post and measure each pin, in the connector on the end of hte cable, to see what resistance you have back to the negative battery terminal. NOTHING over 1 ohm is what you want.*
MAKE DAMN SURE your connectors to the ECU are actually making contact. I HATE the way they designed that connector mess, and I know they were just trying to make it secure and reliable.
I sure wish I lived close to you; this is driving me nuts.
*Touch your meter leads together and look at the meter, it should read zero ohms, (or something like 0.01 or 0.001) if it does not, you can't trust the meter.
Given the symptom, I bet this is gonna be "Stupid easy" when you find it.
And I bet REAL MONEY, it will be a "Ah, I see what happened, makes sense now" kind of moment. .
Originally Posted by pizzaguy
I swear, this is going to be "stupid and simple" when you find it. The ECU is not powering up.
Originally Posted by Jonathandugan20
..... ecu connectors weren't making contact....
God i feel like an idiot!!! Thanks for all your help pizza guy!Sorry to take up soo much of your time
Like I said, I have been down this road many times in 40 years.......................
One other thing, I'd call Rob and tell him what was wrong, if you have not already. This is going to happen again, and that way, Rob can help the next guy faster.
Do not assume you are the only one who will or has encountered this. That connector setup is GOOFY.
Re: No crank after new keys
