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Hey guys,

This is my first post over here. Id like to thank Mopar1973Man for having this forum and for all the information he contributes. The trouble code walkthoughs are an amazing resource.

 

I am trying to resolve P1689 and P0215 DTCs.

 

Truck: 01 QCLB CTD Auto 4wd. Pertinent upgrades: FASS system 95gph, smartry and original quadzilla adrenaline. There are lots of other upgrades, but none that should relate to my question.

 

Backround: Truck was sitting for the better part of two years. When I stopped driving it, it was running well. When I came back to start it again, I had a no crank issue that ended up being a bad ignition switch. After that was fixed it will no crank but not start. It has fresh fuel and chraged batteries.No blown fuses or bad relays that I can identify. I checked for codes both on the odo and the smarty and I have  a P1689 and a P0215. I had a link in my supply fuel line which I subsequently replaced, but those codes existed before and now after that ( I have read sometimes youll throw a P1689 after opening a fuel line). At this point I found the code diagnostics on this site and began to go through them. As a side note, I believe the VP44 is actually bad. I jumped it and still couldnt get the truck to fire. I do have fuel at the inj pump and the lines are bled etc. There is a secondary issue, and I am not getting voltage to the pump as you will see...

 

P1689

After going through the first couple of steps, verifying the codes and checking the connectors are secure and there are no visually obvious breaks or problems I moved to step 3 to verify that I was getting voltage to pin 7 (red/grn) wire on the FPCM, I am getting .1v, so no voltage essentially, to pin 7. The guide then directs you to to the P0215 diagnostic.

 

P0215

1) I have 12.5v to relay 85

2)Relay is good, has 70ohm and was taken from the horn slot which works

3)ECM pins 30 and 49 have 12.5v

4)Relay 86 to ECM pin 36 shows about .3 ohm

5)Relay 86 to ground gives me a reading of between .1 and .5 ohm. It says I should be getting 100 ohm or more.

 

In the guide it states for #5 

"If resistance is less than 100 ohms, repair short to ground in Brown/White wire between PDC and ECM." which seems to be the case. 

 

I am just looking for some reassurance that theres nothing else it could be. I cant understand how I could get a short in the wiring harness just sitting there for and extended time. Has anyone here experienced something like this? I just want to make 100% before I go tearing open the wiring harness. Does anyone have some tips or tricks on how to go about the repair? Would it make sense to tap the brown/white coming out of the pdc and coming out of the ecm connector to verify thats  the problem first?

Any insight would be much appreciated!

 

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2001-Dodge-Wiring-Pg3.jpg

 

So how you test for that is to unplug the VP44 and the ECM and theohm that brown/white wire to ground and see if there is any ohm reading. If infinite then its not shorted to ground. Might check for ohm from end to end to verify the wire in not broken it should read 0 ohms. 

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Just now, Mopar1973Man said:

2001-Dodge-Wiring-Pg3.jpg

 

So how you test for that is to unplug the VP44 and the ECM and theohm that brown/white wire to ground and see if there is any ohm reading. If infinite then its not shorted to ground. Might check for ohm from end to end to verify the wire in not broken it should read 0 ohms.

Thank you for the reply.  Just to clarify (I am pretty green with solving electrical issues!) I want to test ECM pin 36 to a gound, correct. Dumb side question, the ground should be a chassis ground, not the battery, is that right?

For the second part, I assume I would need to disconnect the brown/white at the pdc end. What is the best way to access that. I have never dug into the pdc before. Apologies for the rudimentary questions.

Thanks Mopar1973Man

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31 minutes ago, JHFIII said:

I want to test ECM pin 36 to a gound, correct. Dumb side question, the ground should be a chassis ground, not the battery, is that right?

 

No... You won't see ground through it the condition is right. Being that the relay or cable will be unplugged there is no power to the ECM so the transistor will not switch for ground. Also ECM ground is the passenger battery cable.

 

 

Trivia...

 

Q: Where is the headlight grounds at?

A: In the driver side kick panel. 

 

So just because you tear apart all the grounds under the hood doesn't mean you'll fix anything. You have to have an understanding of what the grounds do and where they are located.

Edited by Mopar1973Man

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Good grief, that explains a lot. No wonder I was getting some weird readings. I need to go back through parts of the 1689 and 0215 code diagnostics. Ive just been chasing my tail. Yeah, I'm just learning as far as electrical goes. Mechanical I am decent at, electrical is new material. Thank you for taking the time, I will report back.

 

ETA one more thing...when I jumped the vp44, theres no reason it would be an issue that I had the leads going to the driver battery, would it be? 

Edited by JHFIII

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6 minutes ago, JHFIII said:

 

ETA one more thing...when I jumped the vp44, theres no reason it would be an issue that I had the leads going to the driver battery, would it be? 

 

No. won't matter the VP44 is stand alone at that point.

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Just now, Mopar1973Man said:

 

No. won't matter the VP44 is stand alone at that point.

Ok good. I thought it was probable that it had died anyway. Normally that wouldnt be good, but I have an II hrvp I never got around to installing on hand. Id rather do that work than chase gremlins!

Edited by JHFIII

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UPDATE

OK with the knowledge that I was using the wrong ground in some of the diagnostics, I re-ran the applicable parts of the p1689 and p0215 diagnotics

 

P1689

1)check

2)No visual problems

3)FPCM #7 to passenger battery ground---No Voltage (.002V)

--at this point it instructs to go to P0215, but I just finished the rest of the P1689 in case it gives any useful info

4)FPCM #6 to battery voltage ---12.5v

5)FPCM#2 to ECM 13 Less than 5ohm? Yes, .2ohm

6)FPCM#2 to ground-- No reading at all

I stopped there and went to P0215.

 

P0215

1)Battery voltage to Fuel Pump relay 85 ---Check, 12.5v

2)Relay reistance is good 70ohm

3)ECM 49 and 30 to battery voltage both show 12.5v

4)ECM 36 to Fuel pump relay 86 less than 10 ohm? Yes .3ohm

5)Relay 86 to passenger battery gound shows .5ohm. Guide says it should be 100ohm

 

So thats where I am. That would seem to indicate that I need to repair short to ground in Brown/White wire between PDC and ECM. Any tips on how and where to start looking, or any further test I can do to make sure that is whats going on?

Thanks!

 

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Run an overlay from the pdc to the ecm. Will be the fastest way to eliminate the circuit.

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Ok, I have re run some of the tests once again.

Something is up.  For step #4 of the p0215 work I am getting a fluctuating reading of about 1.5 milli-ohm from relay 86 to ecm 36. 

If I test ecm 36 to the terminal in the PDC  connector for the brown/white wire then I get .2ohm.

Could that mean the problem is in the PDC?

Edited by JHFIII

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Ok guys, tell me if this sounds reasonable.

The truck was parked outside for almost two years. I had the hood slightly cracked for the trickle charger. I washed it periodically. 

I'm assuming there is a circuit board inside the box. I am wondering if it's feasible the connector for fuel pump relay 86, assuming it does interact with a circuit board, is corroded. 

I saw some pictures of third gens that had something like this happen. I wanted to know if this sounds like a likely culprit to you guys before I go digging into the PDC. My ohm reading from between the PDC connector and ECM connector seem to indicated there isn't a break or short between this two.

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1. Pin # 85 of fuel pump relay is ground.  Ohm test wire for continuity.  If good go to next.  If open       circuit, repair wire.

 

2. Pin #30 of fuel pump relay is battery voltage (12+ volts) all the time.  If good go to next.  If no          voltage check fuse # 3 (25amp)  in PDC.

 

3. Pin #87 of fuel pump relay is switched power (12+ volts) from relay to pin #7 of the fuel injection     pump.  Ohm test the wire from fuel pump relay pin #87 in the PDC to socket #7 in the in fuel               injection pump connector for continuity.  If good go to next.  If open circuit, repair wire.

 

4. Pin #86 of fuel pump relay is used to energize the relay solenoid with voltage (12+ volts) from pin   #36 of the ECM.

Check for voltage at pin # 86 position in PDC.  When key is turned on, voltage (12+ volts).  If no voltage, ohm    test wire for continuity.  If open  circuit, repair wire,  If circuit good,  then there is no fuel pump relay signal (voltage) from ECM.  

 

5.  Bypass relay to test injection pump by using a jumper wire in fuel pump relay socket between pin  #30 and pin #87. The engine should start if every thing else is good. 

Edited by IBMobile
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19 hours ago, IBMobile said:

1. Pin # 85 of fuel pump relay is ground.  Ohm test wire for continuity.  If good go to next.  If open       circuit, repair wire.

I didn't have time to pull the battery to get to the G100 ground, but things like, horn, turn signals etc work, so it seems unlikely.

 

2. Pin #30 of fuel pump relay is battery voltage (12+ volts) all the time.  If good go to next.  If no          voltage check fuse # 3 (25amp)  in PDC.

I have 12v to pin 30.

 

3. Pin #87 of fuel pump relay is switched power (12+ volts) from relay to pin #7 of the fuel injection     pump.  Ohm test the wire from fuel pump relay pin #87 in the PDC to socket #7 in the in fuel               injection pump connector for continuity.  If good go to next.  If open circuit, repair wire.

I have continuity (.1 ohm)

 

4. Pin #86 of fuel pump relay is used to energize the relay solenoid with voltage (12+ volts) from pin   #36 of the ECM.

Check for voltage at pin # 86 position in PDC.  When key is turned on, voltage (12+ volts).  If no voltage, ohm    test wire for continuity.  If open  circuit, repair wire,  If circuit good,  then there is no fuel pump relay signal (voltage) from ECM.  

No voltage to pin 86 with the ignition ON.

 

5.  Bypass relay to test injection pump by using a jumper wire in fuel pump relay socket between pin  #30 and pin #87. The engine should start if every thing else is good. 

When bypassed I have 12v to Pin 7 of the FPCM. So I know the red/green wire is ok. It got too late to start it tonight (neighbors) but I will do so tomorrow so I will at least know what the status of the VP is.

 

Thoughts: Assuming the G100 ground is in order, the ECM is either not sending signal through the brown white wire, or it is and its not getting from the PDC connector to the relay. As mentioned previously, the brown/white wire does have continuity between ECM pin 36 and its respective PDC connector pin.

Perhaps related, I can interact with the ECM with my Smarty. I can upload or return to stock tunes, read and clear codes, etc. I have read the ECMs are pretty tough, but I know they do go bad from time to time.  Does it make sense thinking that the issue has something to do with the circuit board in the PDC? As I mentioned before, it has been exposed to the elements. 

I really appreciate the help so far Mopar1973Man and IBMobile!

 

 

 

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If you ohm tested the brown/white wire from pin #36 at ECM to fuel pump relay pin #86 in the PDC and it's good then you should get 12+ volts when ignition is on or cranking with the starter.   

 

28 minutes ago, JHFIII said:

Does it make sense thinking that the issue has something to do with the circuit board in the PDC? As I mentioned before, it has been exposed to the elements. 

            Do you see any corrosion?  Have any ohm tests shown abnormally high reading?

 

                                  This is the underside of the PDC.  There is no circuit board.

DSCN9784.JPG.7640015a5597587f99d8d589d1e7a39c.JPG

 

 

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3 minutes ago, IBMobile said:

If you ohm tested the brown/white wire from pin #36 at ECM to fuel pump relay pin #86 in the PDC and it's good then you should get 12+ volts when ignition is on or cranking with the starter.   

 

            Do you see any corrosion?  Have any ohm tests shown abnormally high reading?

 

                                  This is the underside of the PDC.  There is no circuit board.

DSCN9784.JPG.7640015a5597587f99d8d589d1e7a39c.JPG

 

 

When I test from ECM 36 to its respective pin in plug/connector that plugs into the PDC I get a rock solid .1ohm.

If I ohm from ECM 36 to relay 86, I get a weird reading, like 5 milliohms, but it fluctuates up and down.

I will test it once again tomorrow, just in case I made some error.

Thank you very much for that picture. I had not been inside that, I dont know why I assumed there was a circuit board.

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Hey guys,

I think I may have finally found the culprit. With the ignition ON the ECM is only sending 7 volts to the brown/white, measured between fuel pump relay pin 86--->85. I'm guessing that is not going to be enough voltage to activate a 12v relay. 

Its strange because as I mentioned I can upload tunes with the smarty, no issues with the wait to start, I can read and clear codes etc. 

Does it sound like I have found it to you guys? Any similar experiences? Recommendations on testing or replacing the ECM?

 

On to the VP. I drained my charged batteries today trying to get her started with the fuel pump relay bypassed

(87--->30). I had injection lines 1,3,4 loosened. 4 spurted fuel immediately.  3 is weeping just the tiniest bit. 1 is still bone dry. I defintely have good fuel pressure 15+psi, and I cracked the vp return until had steady fuel coming out. It didn't take nearly as long to start when I actually installed the FASS when I first bought the truck. Ive read that if you aren't getting fuel spurting much quicker than that, you've got a dead pump. Sound correct?

Thats a hell of a thing, to have an ECM and VP go out.

Thanks guys 

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Just shooting in the dark here, if it's sat for two years where did it sit. Maybe some grounds or connectors got oxidized, maybe mice chewed on some wiring. Just having hard time believing that it ran fine and after sitting for two years it would not start and all the sudden you had to change ignition switch. I would double check wires where you messed with ignition, maybe one of those loose or not plugged in all the way.

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8 hours ago, Dieselfuture said:

Just shooting in the dark here, if it's sat for two years where did it sit. Maybe some grounds or connectors got oxidized, maybe mice chewed on some wiring. Just having hard time believing that it ran fine and after sitting for two years it would not start and all the sudden you had to change ignition switch. I would double check wires where you messed with ignition, maybe one of those loose or not plugged in all the way.

It was outdoors. The ignition switch makes sense to me. It was a little musty in the cab. It wouldn't crank at all. Everything else electrical works fine. The only two things are the ECM sending low voltage through the brown white wire to the fuel pump relay, and the vp (which I suspect was on its way out when I parked it).

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Finally got to the G100 ground. Nearly totally corroded. I'll be doing some wiring tonight and then I'll retest things with the voltmeter.

 

Edit: Actually not as bad as I thought at first once the dremel wire wheel got done with it. Nice and shiny now, though.

Edited by JHFIII

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Update to say that I got it running. The VP44 did indeed need to be replaced. With the relay bypassed it was only pumping lift pump pressure out of one injector line. The old one couldnt even be turned by hand, something definitely bound up in there. A little dab of yellow paint on the new vp44 key was definitely a big help to get it lined up right. Very happy to have it running.

 

I still havent resolved my p0215 code, and I can only start it with the relay bypassed, but at least it roars once again.

All signs say is has to be the brown white between the PDC and ECM.

 

These are the results of the p0215 diagnostic:

1)Fuel pump relay 85(gd) to batt voltage =12v

2)Relay is good 75ohm

3)ECM 30/49 to batt voltage=12v

4)ECM 36 to relay 86 .2ohm

5)Relay 86 to G100 ground = 65ohm

 

Im only getting about 8V from the ecm to relay 86, with the igntion hot.

The brown /white from end to end reads .1ohm.

The brown/white to ground does not register a reading on the multimeter. Im not sure what that means.

IMG_0213.jpg

Ive been hesitant to tap the brown white at the ecm and then the pdc connector and run an overlay wire to see if that fixes it, until I was absolutely certain (which Im still not, but I have a hard time blaming the ECM since its doing nothing else to make me think its on the fritz).

Does anyone know if its possible to fish a new wire through the ECM loom? Or am I just better off running it on the outside. The last thing Id want to do is screw up other wires in the loom. 

Thanks guys

 

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3 hours ago, JHFIII said:

Does anyone know if its possible to fish a new wire through the ECM loom? Or am I just better off running it on the outside. The last thing Id want to do is screw up other wires in the loom

I'm sure it's possible but I would just run it on the outside then you know what it's for, I'm guessing that's for your lift pump right. some people just bypass ECM all together and run lift pump off a toggle switch through a relay, the only problem with that I heard off is safety in case of an accident. That and forgetting to turn it on or off, maybe get a toggle with LED built into it.

Edited by Dieselfuture

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5 hours ago, Mopar1973Man said:

 

Too high... I would chase that ground connection. That should be 0 Ohms. So it might not be pulling the relay closed all the way. 

Should that reading be taken with ignition on or off?

I read the #5 step as meaning that I should have exactly 100 ohms, but sounds like I'm mixed up on that. 

Does ECM sending 8volts through the brown/white, ignition on sound correct? (measure with the ecm harness connected, igntition on)

I have to check my notes, but I believe I measured the g100 gnd connector (disconnected) to relay 85 and got .1ohm.

My confusion is that the wires all appear to show continuity, but something gives.

For the record, I did clean g100 thoroughly. Once I got a surface rust and crud off , it actually looked pretty secure and clean.

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JHF,

 

If you were actually checking 86(this is the ECM output to fire the relay) to ground (ignition off.... ignition on would/should blow your meter) you could get a couple different readings.  with the relay in the socket, you would read resistance through the coil which should be in the range you said.  If you did it with the relay removed, you are reading backwards through the ECM and power supply.... it will be an odd reading.

 

Where did this diagnostic list come from?  I can't find it in my manual.  I would like to read what/why they are looking for.

 

I have attached the FSM page for the relay. 

 

To diagnose this system, I would:

1) remove relay. 

2) with the key on, put the black meter lead to ground (a good ground) and put the red in 86.  You should have 12v.

3)  have someone turn the key off while reading this.  The 12v should go away.  recycle the key on. it should come back.

4)move the red lead to cavity for 30.   This should have 12v whether the key is on or off. 

5)make sure key is off.  put meter on ohms.  touch red and black probes to each other.  This should read about 0.1 ohm or so.

6)put black lead on good ground, put red lead in 85.  You should have about 0.1ohms or so again.

7) Disconnect the wiring harness from the VP 44. 

8) with the black placed in 87.  put the red on terminal 7 (red / light green) at the injector pump.  this should read 0.1 ohm or so.

 

You have now confirmed that the

1) ECM is outputting 12v when it is supposed to.

2) fuse 3 is ok.

3) the wire between 85 and ground is good. (this will let the relay shift when commanded)

4) the wire between 87 and the injector pump is continuous.

 

The only thing we have not proven is that the VP44 is "seeing" the signal sent.  But if all the above checks out, it should be close.

 

The only other test we could do is put the relay back in and check Terminal 7 to see if it gets 12v.  but that would require the VP44 be disconnected, and it is possible that will throw other codes.  (if needed we will talk about how to set up a back probe.... but that is scary for weather proof type connectors.) 

 

HTH

 

Hag

 

 

2001 FSM Ram 8w-30-37.pdf

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