I'm working on diagnosing a P0237 code.  I installed a fuel boss and primed the system by cracking the injectors resulting in fuel down the side of the block. Wondering if that could have caused it or I bumped something out of place. 

I removed the MAP sensor and cleaned it, appeared in good condition. 

Attempting to follow the steps :

 

Though, my OBDlink mx is unable to read MAP voltage. I'm getting Mass air pressure readings, could the boost on the Quad be at fault? 

Going to disconnect the harness and see if I can get a voltage reading off the plug with the multimeter tomorrow. 

So what I would do is unhook the Quadzilla completely for a test and clear the codes and go for a drive for 10 to 20 miles and then check for codes again. If the codes are gone then the Quadzilla is at fault with a boost fooler issue. If the code returns the MAP sensor or wiring on the stock side is at fault. 

The code is constant, I'm unable to clear it with my OBDlink Mx. I returned it to stock by removing the Quad and drove for a bit. Code remains as well as no turbo function besides spinning with RPM's. Can R/O the quad

Going to attempt to get a voltage off the orange map wire. Hoping it's in the 4.7-5.3v range with the sensor as the culprit. Not very electrically inclined and messing with the ECM resistance testing is a bit daunting... 

I also noticed my oil pressure gauge rests at 30 when it use to point in the upper range when cold and descend as the engine got to temp. 

Thanks for the input

Be aware a bad oil pressure sensor can foul the MAP sensor. This is a little secret from another member. 

17 hours ago, Mopar1973Man said:

Be aware a bad oil pressure sensor can foul the MAP sensor. This is a little secret from another member. 

I checked the wiring diagram, see that both sensors have a 5v power link. When the oil sensor goes does the MAP fail somehow? 

I tested the orange wire at the MAP connection and it was ~5.03v. Guessing I'll have to order a map and oil sensor from genos in hope that it resolves. 

 Another thing to check is your oil pressure sensor connector. See if it has the orange wire going to it. The 02 wiring diagram shows the 5v shared. My spare harness only has one wire going to it and it is not orange, gray with violet tracer IIRC. The orange wire going to the Map sensor has no splice and runs directly to the MAP. This has to do with the late model oil sensors only being a switch and not a sensor. Not sure how far back this goes nor whether that sensor can effect the MAP since they are not interconnected in any way. 

 That being said I am not the electrician by any means. Maybe someone else better versed might be able to expand on it.

3 hours ago, dripley said:

 Another thing to check is your oil pressure sensor connector. See if it has the orange wire going to it. The 02 wiring diagram shows the 5v shared. My spare harness only has one wire going to it and it is not orange, gray with violet tracer IIRC. The orange wire going to the Map sensor has no splice and runs directly to the MAP. This has to do with the late model oil sensors only being a switch and not a sensor. Not sure how far back this goes nor whether that sensor can effect the MAP since they are not interconnected in any way. 

 That being said I am not the electrician by any means. Maybe someone else better versed might be able to expand on it.

I'll take a look when I get the new sensor in. Will I be able to access the oil pressure sensor without pulling the fuel filter housing? Looks like it might be a tight squeeze. 

3 hours ago, CAMG3X said:

I'll take a look when I get the new sensor in. Will I be able to access the oil pressure sensor without pulling the fuel filter housing? Looks like it might be a tight squeeze. 

Yeah it is a bit cluttered down there. My filter canister only has 2 bolts and can easily be moved if it is in the way. I have never unplugged mine,  never had reason to.

On 9/19/2018 at 10:06 PM, dripley said:

Yeah it is a bit cluttered down there. My filter canister only has 2 bolts and can easily be moved if it is in the way. I have never unplugged mine,  never had reason to.

My oil pressure sensor harness has 3 wires including the orange 5v, so I'm assuming it is linked to the MAP 5v. The double wire must be only with the 2002's. 

I replaced both the oil sensor and Map sensor. The P0237 code cleared right away and the oil pressure gauge is acting normal now. I should have probably done one sensor at a time to see which was the culprit. 

Did notice that my oil pressure sensor was not in very tight at all, probably could have undone it by hand, replaced the new one nice and snug. 

Thanks for the help guys! These trucks confuse the heck out of me sometimes

Your welcome.

17 minutes ago, CAMG3X said:

My oil pressure sensor harness has 3 wires including the orange 5v, so I'm assuming it is linked to the MAP 5v. The double wire must be only with the 2002's. 

I replaced both the oil sensor and Map sensor. The P0237 code cleared right away and the oil pressure gauge is acting normal now. I should have probably done one sensor at a time to see which was the culprit. 

Did notice that my oil pressure sensor was not in very tight at all, probably could have undone it by hand, replaced the new one nice and snug. 

Thanks for the help guys! These trucks confuse the heck out of me sometimes

I am going to have unplug mine and see. My spare harness is the one with the wire to the sensor. I bought as an 02 harness years ago. I have bought but yet to install a new oil pressure sensor for mine and it only has 2 prongs in the connection. My spare would fit it. So I am going on a bit of an assumption for now.

 Happy to see your problem has been solved and you are welcome for the help. I get a plenty of it around here myself.

 @Mopar1973Man You ever checked yours for the number of wires going to the sensor?

I have one on my 02

Just now, Dieselfuture said:

I have one on my 02

One wire I take it to the sensor?

31 minutes ago, dripley said:

One wire I take it to the sensor?

Yes, going of memory when I changed oil sensor but when I did I was thinking how it can be a 5 volt reference, an oil sensor and whatever else all on one wire. So I'm pretty sure it was a single wire, although plug looked like it was made for 2 wires. 

1 minute ago, Dieselfuture said:

Yes, going of memory when I changed oil sensor but when I did I was thinking how it can be a 5 volt reference, an oil sensor and whatever else all on one wire. So I'm pretty sure it was a single wire, although plug looked like it was made for 2 wires. 

My spare harness has a 2 wire connector to the sensor but only 1 wire. No 5v signal and no shared ground wire. Only a wire to the ECM.

11 minutes ago, dripley said:

My spare harness has a 2 wire connector to the sensor but only 1 wire. No 5v signal and no shared ground wire. Only a wire to the ECM.

Yes I think that's how it is on mine. 

Been a 3 wire sensor for the entire span of 1998.5 to 2002... I don't know of any single wire sensor on our trucks there is either 2 wire for temperature sensors. Then the pressure sensors like MAP and Oil have always been 3 wire.

 

@Mopar1973Man

The 02 wiring diagram is different than the one you posted. It only has the oil sensor and the map sharing a 5v signal wire and not the cam sensor My spare harness has a 5v to the map and no splices. One solid wire straight to the map. The connector for the oil pressure sensor is only 2 pronged and not 3. I will check it again when I get home and check the one on the truck. Could this be because the late models are only swithches and not sensors? All the switch does is tell the ECM we have oil pressure and the ECM takes over from what i have read here. If that is the case is one wire not sufficient to comunicate that to the ECM?

 

The other really strange thing is what in the name of Hades is the chicken man doing debating electrical systems in the first place? There is something wrong with that picture.