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Cardoctor71
Cardoctor71, ASE Master Technician
Category: Dodge
Satisfied Customers: 672
Experience:  35 years experience in the automotive and Lt truck repair business, owner Cardoctor LLC Guthrie, OK
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I have a 2007 Dodge Ram 1500, with a hemi. I was driving it

Customer Question

I have a 2007 Dodge Ram 1500, with a hemi. I was driving it last week, everything was fine, gauges good, then all the sudden the check gauges light came on, I looked, but didn't see anything wrong, then the truck quit on me. I started it back up, seemed fine, drove about a quarter mile, parked it for about an hour. Came back, started it up, drove about a half a mile, less than 10mph on a college campus, and the truck quit on me. Wouldn't start, turned over fine, just no fire. I let it cool down a bit, not much I mean it was 103 outside and naturally it quit right in the sun, but I piddled with it for about 15 minutes, cleaning battery cables, looking for broken/loose/missing wires/connections, didn't find any. I tried to start it again and it did start, but not good, now here is what I'm seeing. Rough idle, zero throttle response, zero oil pressure on the gauge, check engine light is on, flashing red lightning bolt, check gauges light, traction control light on. My handheld was throwing a p0335 (crank position sensor low voltage), p0122 (throttle/pedal position sensor low voltage), and just today threw a p0522 (oil pressure sensor switch low). That one wasn't there the day this all started. So, here is the course of action I have taken so far. Replaced the crank position sensor (cheap and easy), replaced the throttle body (has the throttle position sensor built in, not so cheap, but still easy), replaced the pedal position sensor (came off a wrecked junkyard truck, should have been working when it was wrecked), I have checked several ground wires and connections, to make sure they are tight and clean, can't guarantee I didn't miss one, but I got most of them, checked the oil and antifreeze levels, both good, I am about to do a compression check on it, and since I'm getting a low oil pressure code, test the oil pressure sending unit, maybe even put a manual gauge on the oil line to check the actual pressure. What I am wondering is, what have I missed? Will low oil pressure cause it to go into full blown limp mode? And really, this isn't limp mode, the transmission is shifting even driving along at an idle, I'm just not sure, if it's not a burnt valve or broken valve spring, I'm afraid it is going to be a short somewhere in the wiring harness, or even a bad pcm. I've always been a ford man, so any ideas from someone with experience in these dodge hemis will be welcomed
JA: Does the light stay on, or does it blink?
Customer: Blinks
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: Yes and really, I just wrote all that
JA: Anything else you think the mechanic should know?
Customer: All in the first message
Submitted: 6 months ago.
Category: Dodge
Expert:  Cardoctor71 replied 6 months ago.

All issues and codes appear to come back to low voltage to the sensors, the lightning bolt indicates do not drive, probably related to low voltage on the oil pressure switch, remove the alternator and have bench tested, battery as well. Until you solve the low voltage issues all kinds of false codes are going to set and the engine computer is going to try to protect the engine accordingly by forcing it to stall. Definitely check the oil pressure but unless there is engine noise to go with the issue it is probably fine.Please accept my answer, if you have any further questions I will answer them until you are completely satisfied with my answers.

Customer: replied 6 months ago.
Naw, not a charging issue, battery tests at 12.5 volts sitting, then 14.5 when it's running, so I'd say the alternator is doing its job. Any other ideas?
Expert:  Cardoctor71 replied 6 months ago.

Power and grounds to the pcm need to be checked, as well as grounds on the engine ,possible pcm failure or every one of the sensors setting codes need to be replaced. low voltage issues are tough and time consuming even for the most highly qualified technicians .

Customer: replied 6 months ago.
Well.... I have replaced all the sensors throwing codes, except the oil pressure sending unit, since that one just came up. How does a fellow check the pcm? I mean is there any way to verify that it is good or bad? Also, is there a common ground wire that could short the three sensors throwing codes? I've noticed they are all in the same loom. Just trying to go as far as I can myself, before getting raped by the dealer.
Expert:  Cardoctor71 replied 6 months ago.

Checking the pcm requires an accurate, color coded wiring diagram. a pinpoint pin value chart,and is extremely tedious even for a technician with at least 20 years experience, not something I would attempt if I were you, but then again I don't know your skill level, Have you confirmed the oil pressure is normal, no engine noise?

Expert:  Cardoctor71 replied 6 months ago.

Please accept my answer, if you have any further questions I will answer them until you are completely satisfied with my answers.