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5v ref

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5 years 1 week ago #28553 by Ernrod
5v ref was created by Ernrod
2002 dodge ram 1500 5.9l:
I have a no-start; no com. at data link; replaced cam and crank sensor; I have good ground; 5v ref. Is 5.2 volts; all fuses and replays are working; I only have 1 power source at transmission relay (pin 30), I checked for second voltage supply to relay with key on and cranking engine but no second voltage supply to relay.
I did find transmission range sensor (park/neutral) bare wire rapped are another bare wire.
Any suggestions?
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5 years 1 week ago #28555 by chief eaglebear
Replied by chief eaglebear on topic 5v ref
is there power at dlc

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5 years 1 week ago #28556 by Ernrod
Replied by Ernrod on topic 5v ref
Yes

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5 years 1 week ago #28557 by Ernrod
Replied by Ernrod on topic 5v ref
I have no fuel pressure and no spark

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5 years 1 week ago #28558 by Ernrod
Replied by Ernrod on topic 5v ref
Is 5v ref. Ok at 5.2 volts?

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5 years 1 week ago #28559 by Ernrod
Replied by Ernrod on topic 5v ref
Also, the truck will crank and not crank at times

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5 years 6 days ago - 5 years 6 days ago #28570 by John Curtis
Replied by John Curtis on topic 5v ref
You may have a bad ground or an open circuit if your fuse that controls the PCM/ECM is not blown. I would check for blown fuses first since that's the easiest thing to notice though I don't think that is going to be your problem.


Being that you have an intermittent crank/no crank... the PCM shouldn't have anything to do with that. That being said, that would be my starting point for diagnosing the problem.

Check your grounds at the fuse box. Maybe swap the relay even though you checked it and also check the voltage in the relay sockets. Then focus on the starter circuit. Check for power on fuse #14. Focus your attention between the ignition switch and the starter motor.

I wouldn't go any further until you are getting crank every time your turn your key.

Making Pressure Differential Sensors (PDA Sensors) for pressure pulse diagnostics.
Currently servicing Central Texas.
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Last edit: 5 years 6 days ago by John Curtis.

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5 years 6 days ago #28572 by chief eaglebear
Replied by chief eaglebear on topic 5v ref
maybe monitor crank signal at computer the fact that it is intermittent might be an ignition switch but with no fuel pressure and no spark leads me to believe your crank signal is cutting out somehow I would go through crank and cam circuits thouroughly make sure signal is getting to computer also we must determine what module is in charge during cranking and which one is in charge during run

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5 years 6 days ago #28608 by Ernrod
Replied by Ernrod on topic 5v ref
I separated the 2 wires that were touching but I still don't get a signal to the switch wire, brown yellow wire

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5 years 6 days ago #28609 by Ernrod
Replied by Ernrod on topic 5v ref
Looks like those 2 wires have been touching for some time. I'm thinking those wires may have shorted the signal from the pcm (Brown/yellow). Or caused a open somewhere

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5 years 6 days ago #28610 by Ernrod
Replied by Ernrod on topic 5v ref
If the transmission range sensor sends a signal to pick would that be sent through the brown/yellow wire?

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5 years 6 days ago #28611 by Ernrod
Replied by Ernrod on topic 5v ref
I'm assuming the transmission range sensor is bad, because I get no signal during cranking

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5 years 4 days ago #28669 by Ernrod
Replied by Ernrod on topic 5v ref
Yes, I have the 2 powers at starter relay

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5 years 4 days ago #28670 by Ernrod
Replied by Ernrod on topic 5v ref
Should I have 2 powers at transmission relay?

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5 years 4 days ago #28671 by Ernrod
Replied by Ernrod on topic 5v ref
What shouldould be my ground measurement at the pcm? It has 2 ground wires

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5 years 2 days ago #28711 by Ernrod
Replied by Ernrod on topic 5v ref
Is that 50m ohms?
I'm still stuck on the transmission relay, park/neutral switch. I only have one power feed at the relay, with key on and cranking. I checked for signal at computer (pin 6 brn/yel) I get no signal on cranking.
I placed the truck in neutral and received a signal at Brn/yel wire but not in park. The signal in neutral is intermittent.

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5 years 2 days ago #28712 by Ernrod
Replied by Ernrod on topic 5v ref
Is that 50m ohms?
I'm still stuck on the transmission relay, park/neutral switch. I only have one power feed at the relay, with key on and cranking. I checked for signal at computer (pin 6 brn/yel) I get no signal on cranking.
Yes, I have power at starter solenoid (pin 87) with cranking
I placed the truck in neutral and received a signal at Brn/yel wire but not in park. The signal in neutral is intermittent.

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4 years 11 months ago #29040 by Ernrod
Replied by Ernrod on topic 5v ref
I decided to start over.
What I discovered, I tested the "engine control relay" and I have the 2 power sources but during cranking I'm not getting voltage at pin 87 from pin 30.
Do I have a bad ground or a shorted 02 sensor or injector? Which share pin 87

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4 years 11 months ago #29044 by Ernrod
Replied by Ernrod on topic 5v ref
Key on, I get .18v, cranking I get .18 volts at pin 87.
Test Ground on pin 87 I get .428 ohms

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4 years 11 months ago #29067 by Ernrod
Replied by Ernrod on topic 5v ref
Pun 30 and 85 have 12V

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