2002 Dodge Ram 1500 5.9L Crank no start

Hello all,

As my title states I have a 2002 Dodge Ram 1500 5.9L crank no start. My truck sat for a few weeks. I turned key to the on position and my gauges started as normal but started dropping at different times of each other. Battery gauge went to 0 and then gas to empty, then oil to empty. I tried to start cranks no start.

I then turned the key off then back on and the battery gauge works but not the gas or oil gauge. Tried to start crank no start. Then I have my wife turn the key off and on gas gauge turns on this time and I hear/feel the relay #57 clicking engine control relay/ASD and the truck starts. Then we turn it off back to square one no gauges working. It was the only time it started. Relay #57 stopped clicking so I figured it was a bad relay and swapped it with another relay and nothing. I then tested all fuses and they all worked even the relays. I know from watching videos even though the relays click it don't mean their good. So I bought a new one and replace #57 and nothing.

I then decided to jump pin slots 85 & 87 with a wire. The gauges all work and the truck starts. I removed the wire and truck stops. I know I'm getting close. Weather is bad in Chicago/cold. I work in spurts then run in the house to thaw off. Not sure what cables to check next as I have no diagram. Trying to get one from my mechanic. I'm not sure at this point if it's a cable, tipm/fuse box, or PCM/ECM issue.

Like I said before I feel like I'm so close. I'm hoping this makes sense to someone on the channel and can help me in figuring this out. I'd greatly appreciate the direction or answer to my issue. I'll be out of town next week but hope to get my truck running again once I return.

Thank you...
 

pdfhost.io/v/dcpD9Daid_2002_Dodge_Ram_1500_59L

The problem is between terminal 86 of the ASD relay socket and pin 3 at the PCM C3 connector. The PCM should provide a ground for 3 seconds at key on engine off, then switch off, and a full ground while engine is cranking and running. I don't believe you have a crank sensor issue otherwise your fuel pump would not run.

KOEO and terminal 86 inside the relay socket should light a test light connected to battery positive for 3 seconds. If that doesn't work, check this wire at the PCM. If you install the ASD relay back in, the battery voltage should make its way back to the PCM pin 3, C3, if wiring integrity is good from the fuse box to the PCM.

@ferris. I'll try and get out there today and try what you suggest. I'll repost results once complete. Thanks for providing next steps. ??

I also want to add that I just realized the pins I bypassed or jumped with the wire were pins 30 to 87 on relay #57. Not what I had above. I'm not sure if this changes everything but I needed to add this. Also, when I tested the pins in the TIPM/fuse box pins 30 and 85 power without ignition on. With ignition on pins 30, 85, 86 power with pin 87 nothing/ground.

Thanks..

With ignition on pins 30, 85, 86 power with pin 87 nothing/ground

Were those tests done with a test light or multimeter and was the relay out of the box?

86 should not have power. If you had the relay installed, remove it and check 86 again. If the relay was removed, how many volts did it have and can it light a test light?

I've condensed the wiring diagram for easier viewing.

 

@ferris48 Appreciate the feedback. When I tested I did it with a test light connected to negative and the relay removed. Direct connection to the pins on the fuse box. With ignition off pins 30, 85 light up and with the ignition in the on position will light up pin 87 as well. But no light from pin 86.

I did not try moving the light cable from the negative to the positive for pin 86. I'm traveling this week and hope it's a little warmer to work outside as it's been really cold lately in Chicago burbs/ frostbite type weather? I'll move the cable to positive and try pin 86 again and see if I get light or not. I should also have a multimeter when I get back as a buddy has one to borrow.

Also thank you for the diagram as I'm flying blind. I'll return next Wednesday and give this a go again. I'm determined and with the help here I'm sure an answer will come up. I don't want be a parts thrower ? I really want to learn how this works.  Like I said before we're close as everything works once I bypass/jump pins 30 & 87 with a wire. Thanks again!!!!

@ferris48 I'm back and confused now. I used a test light without relay installed. Tested Pin 30 & 85 light up with ignition off. I then turned it to the on position and no light on pin 87 where I did before. I moved the light cable to the positive side of the battery then tested pin 86 and nothing.

I then used a power probe . Tested pins 30 & 85 power 12.3. then tested pin 87 which showed 0 beep ground. Then I tried pin 86 and got nothing even while trying to crank it

I'll add pictures. Hopefully this makes sense. I wanted to add an update. I'll look at your diagram next.

Also, I want to add that I tried another fuse box and got the same results. Only works when I use wire between pins  30 & 87

Thank you

With the ASD relay installed and the key out of the truck, check for voltage at the PCM C3 connector (Service info says C3 should be a gray connector), terminal 3, a dark blue wire with yellow tracer. This wire should have voltage on it at the computer until the computer provides a ground. We can use this to check if the wire is intact all the way back to the engine computer. You can disconnect the engine computer for this test and you can front probe, back probe or use wire piercers for this check. Once you've identified the wire, and it has battery voltage on it, which it should, it should go out if you remove the ASD relay if you've correctly identified the wire at the PCM harness.

     

@ferris48 sorry for the delay with work and weather not cooperating I finally was able to check this out. I believe I was able to locate the cable. I have power on the blue/yellow cable on gray connector going to ECM pin 3. When I remove the relay I get no power at pin 3. So I believe I found the correct cable per your instructions. Not sure on next step? Bypass still works when I use a wire. I will add pics. Thanks!!! Oh and my connectors are gray, white, and black top down on ECM

14.4 v with key off? Are you using a battery maintainer?
Do you maintain the voltage with key on or in the start position? If yes, the PCM is not controlling the relay.
Does the tach bounce or does the scanner show an increase in RPM during cranking?

@Monde

Hello, and thanks for the feedback. I did have the battery connected to a battery charger. I forgot to remove it before testing. The key was also in the off position. So the voltage seen is with the key off. When I get home I will try with the key on and crank to see if numbers change. I will also check what numbers show when the key is in the on position.
I will post results soon.

Thanks again.

Let me state that i'm not a mechanic by profession and the following is not an approved form of repair. From what I'm reading so far your engine computer's bad because it's not grounding the ASD relay. I posted a wiring diagram and powers are on Connector C1, pin 2 and 22. Grounds are on pins 31 and 32, same connector.  Check those. Give the harness a good shake and make sure any reading you take stays rock steady. I know it's a shitty repair job but I think this hack job of a repair may just work.

Here's the link to the wiring diagram again: pdfhost.io/v/dcpD9Daid_2002_Dodge_Ram_1500_59L

         

I'm going to be able to check after work today. When you say connector c1 which which one is that? I have a gray, white, and black connector. Also, I'm new to diodes and if I try this I'm not sure what to buy. I'm willing to try it if it will help others if it works. Thank you and @Monde as I will test once home and provide readings

Well Connector 3 was the one you were working on, Connector 2 is the one in the middle, so Connector 1 has got to be the other, other one, right?

As for which diode to get i'm not sure either. I'm just familiar with the electrical symbol on the schematic I never had to handle one myself. My guess is to pick one that's rated for the current draw on the circuit. Would choosing a 10 amp diode for a 1 amp circuit be overkill, i don't know.

Anyways, I don't know the current draw of the control side of a relay coil off the top of my head. Perhaps your current reading will tell us exactly how many amps is on the ASD control circuit. Then take that number and multiply it by 2 because the fuel pump driver will be doing double duty with the addition of the ASD relay in parallel.

? I figured this would be the case after I sent the reply. I'm going to reply in one as @Monde also provided feedback

@Monde I removed the battery charger and tested again o c3 pin 3 with a 12.5 reading. When cranking the reading dropped to 11. Nothing moved with the rpms. On the dash I see the rpm needle move from below zero to Zero when the key is turned to the on position but does nothing when cracking.

@ferris48 I checked the connector and pin 3 looks fine. I did add a ground as you suggested and I could hear the relay clicking. I also tried to get amps but not sure if I did it correctly. I'll add pics but I wasn't getting a reading.

I also tested connector c1 pin 2 has power pin 22 showed numbers around 11 but my probe didn't beep like it did with pin 2. I think I need to spray something on this connector as I couldn't even push a pin into it. Pin 31 was ground but I don't have a port 32. The connector only goes to 31.

If it's the PCM then I'll try the diode. Maybe my mechanic has one I can have.

I'll wait for directions in order to make sure I tried everything before moving on to the hack ? it would be cheaper than looking for another PCM... Thanks again

If pin 86 is not being grounded by the pcm, you may have an input problem. Can you scope the cam and crank sensors? I am pretty sure that you don't have spark , injector pulse and fuel pump operation. Let us know if you are missing any of those mentioned above.
Tipm usually misbehave when they go bad. Keep that in mind.

When you say scope, is this just another way of saying use a tester and see if some connections are providing input/data?

Sorry, I'm new to all this and learning along the way. I know that the fuel pump and gauges turn on when I do the bypass with the wire on the fuse box when I remove relay #57 and the truck starts. I've also driven it around my neighborhood and it drives fine. Without this bypass the gauges and pump don't engage.

So, I'm not sure what the scope entails and what tools I will need to do this?

Thanks for the help.

Just sent a reply to your message... Thanks

If the truck runs when you ground the ASD relay, you may have to replace the PCM due to a bad transistor ( driver). The inputs are there. If not, the truck would have not run when the ASD relay were grounded.

Yeah, when I bypass pins 30 & 87 on the fuse box with a wire the gauges and fuel work and I'm able to start it. So does it sound like I should try the diode? I'll also check if I can find a repair place for PCM or a replacement of the PCM.... Thanks!