P0336 No Tach, Lack Of Power

[Blakehenryy]

Just picked up the truck from a buddy, it’s a 1999 Dodge Ram 2500 24v Cummins. Sold it to me for a good deal with one problem code p0336 no tach, causing a lack of power. He told me he replaced the sensor with many different brands, and got them ecm tested and the tach worked on bench. The oreillys brand sensor works the best, works for 3 seconds and tach dies. He called a mopar friend of his and he told him to get a cummins brand crank and cam sensor. I got a cummins crankshaft sensor and tach didn’t move. Recorded live data from my code scanner and my OBD2 is able to read my RPMs, but nothing on the dash. I’m stumped

[IBMobile]

If you keep replacing the crank sensor and get the same result then it's not the crank sensor.  The ECM was good when tested so new sensor and good ECM then may be bad connector/wiring.   I would start doing some doing some volt/ohm testing on that circuit. 

Read this and do the tests then let use know what you find.

 

 

[Dieselfuture]

I have a spear ecm programmed to my truck and if I use it my tack will randomly drop to 0 on cluster but in quadzilla it still shows rpm. It will set a 1698 code. Switch back to the other ecm and no problems. Not saying it's your ECM but it could be. 

Like IBMobile mentioned start with that thread and check wires.

Another question is have you checked ac noise and done all the ground mods. It will prevent future electronic failures. 

[Mopar1973Man]

Remember excessive AC noise will pollute and hall effect sensors like crank, cam, ABS, etc. Creating false speed signals.

[Me78569]

Was the engine ever swapped.

[Blakehenryy]

Sorry for the long time with no update. I was running some test on it and in the process I fried the oem crank sensor, Anyways. I tested the continuity on all 3 wires from the sensor to the ECM and all 3 passed. Turns out I was wrong on what pin was what. Signal is pin #16, ground is #4 and constant 5v is #3. I tapped into the sensor side signal wire while running and I get a bunch of voltage jumping, so I guess that passes. So what’s next to test? Also, I put the old oreillys one back and the Rpms started to working for 5 seconds then tach die again. but I noticed with the 5 seconds of it running it sounds like it runs bad, but once the tach dies it’ smooths out.

On 1/12/2019 at 12:24 PM, Mopar1973Man said:

Remember excessive AC noise will pollute and hall effect sensors like crank, cam, ABS, etc. Creating false speed signals.

 

This question is actually for you. I posted the same topic in cummins forum and a guy direct me to your website, where you did a break down on how to test the p0336. And now I’m stuck. I’m on #8 where it says “ Ensure CKP sensor connector and ECM connector are still disconnected. Using ohmmeter, checkresistance between ground and terminal "C" (Gray wire) on CKP sensor connector. If resistance is 5 ohms or more, replace ECM. Perform TEST VER-5A . If resistance is less than 5 ohms, repair short to ground on Gray wire between CKP sensor and ECM. Perform TEST VER-5A .” I did this and I got OL on the ohmmeter. So I put the meter on continuity, the ) ) ) symbol, and I touched one end to the C terminal and the other on ECM pin#17 and got a tone with 0.07.soooo that’s where I’m stuck do I listen to the OL, and what does that mean? Or since I got 5 ohms or more @ 7 ohms I need an ECM?

 

just for a quick link to what I’m talking about

On 1/12/2019 at 12:43 PM, Me78569 said:

Was the engine ever swapped.

Original motor

[Blakehenryy]

Just a quick update: just out of curiosity I decided to test all the pins in the ECM to see if it had continuity with the signal wire and turns out pin#17,30,49 all have a tone. Pin #17 is the crankshaft position sensor signal wire but #30 and #49 are grounds and when I giggle the harness the tone goes in and out. So I’m starting to thing that signal wire is being grounded inside the harness

[Dieselfuture]

It could definitely happen, this is not the first case. @dripley knows all about how to giggle a wiring harness. I believe there is a ground splice just before ECM, it's on my list to do also.

[Mopar1973Man]

Crank sensor signal is frequency of AC voltage not DC. Its not the AC voltage you worry about but the frequency.

[Blakehenryy]

22 hours ago, Mopar1973Man said:

Crank sensor signal is frequency of AC voltage not DC. Its not the AC voltage you worry about but the frequency.

 

I thought I was checking for resistance? So I have it set, on my ohmsmeter, to 400 ohms and all I get is OL when I do one end on ground and other end on terminal C

22 hours ago, Dieselfuture said:

It could definitely happen, this is not the first case. @dripley knows all about how to giggle a wiring harness. I believe there is a ground splice just before ECM, it's on my list to do also.

I’m hoping it’s something that simple. This truck was my buddy’s who sold it to me for a steal. When he got the truck it had the p0336 issue, but he couldn’t figure it out. So I bought from him for $4,000

[dripley]

There is a ground splice in the harness near the VP and another 5v splice for most of the sensors closer to the ECM. The oil pressure sensor and MAP are on a seperate 5v. My problem was the MAP. But strange part was I found a break in the other 5v circuit for the balance of the sensors, but when I fixed that my MAP sensor problem was fixed. I never had any problems with the other sensors. Since I am an electrical midget I cannot explain this I just know it worked.

 

[Blakehenryy]

2 minutes ago, dripley said:

There is a ground splice in the harness near the VP and another 5v splice for most of the sensors closer to the ECM. The oil pressure sensor and MAP are on a seperate 5v. My problem was the MAP. But strange part was I found a break in the other 5v circuit for the balance of the sensors, but when I fixed that my MAP sensor problem was fixed. I never had any problems with the other sensors. Since I am an electrical midget I cannot explain this I just know it worked.

 

Well I appreciate the input buddy! I’m thinking that my signal wire on the sensor side is grounding out. Just because the other two pins on the ECM #30 and #49 are grounds and maybe they are just rubbing to gather or something. I’m just hoping that @Mopar1973Man can tell me why it’s giving me the OL when I test the terminal Cand ground resistance or what the OL means.

[dripley]

1 minute ago, Blakehenryy said:

Well I appreciate the input buddy! I’m thinking that my signal wire on the sensor side is grounding out. Just because the other two pins on the ECM #30 and #49 are grounds and maybe they are just rubbing to gather or something. I’m just hoping that @Mopar1973Man can tell me why it’s giving me the OL when I test the terminal Cand ground resistance or what the OL means.

@IBMobile is another one who can help with that. It is definitely over my head.

[Mopar1973Man]

OL = over load. In ohm is infinite ohm. Which means open wire or broke wire.

[Blakehenryy]

2 minutes ago, Mopar1973Man said:

OL = over load. In ohm is infinite ohm. Which means open wire or broke wire.

Okay, with that being said am I suppose to have some type connection with the signal wire and a ground? Cause I have continuity with pin #30 and #49 which are grounds. Or should have 0 continuity with those 2 ground wires with the signal and only have continuity with #17, which is the crankshaft sensor signal? I’m just really confused cause I’m no wiring genius, all I know how to wire is simple things like a light bar haha. I’m sorry if you have to dumb it down for me I just don’t get it with wiring haha

@Mopar1973Man the part that’s just confusing is the instructions tell me that if I get more than 5 ohms it’s ECM. If it’s less than 5 ohms it’s the wiring and I’m just not getting ethier 

[Mopar1973Man]

Sensor ground is not body grounds. Sensor grounds are reference to 5V generator not body ground.

[Blakehenryy]

1 minute ago, Mopar1973Man said:

Sensor ground is not body grounds. Sensor grounds are reference to 5V generator not body ground.

Okay now I’m starting to understand. So it’s the signal wire that it is grounding out causing it to say it’s a broke wire. Correct?

[Mopar1973Man]

Testing for pinched or grounded wire required but ends to be open. So unplug the crank sensor and ECM. Red probe on the wire. Black probe on clean part of the block.

 

Good wire = OL

Bad wire shorted to ground = 0 ohms.

[Blakehenryy]

1 minute ago, Mopar1973Man said:

Testing for pinched or grounded wire required but ends to be open. So unplug the crank sensor and ECM. Red probe on the wire. Black probe on clean part of the block.

 

Good wire = OL

Bad wire shorted to ground = 0 ohms.

Okay, that’s exactly what I did and put the ground on the fuel filter housing bolts and tried body and same results OL. So wire is good but does that mean ECM is bad sensor the wire is good? Or do I keep going with the test?

[Mopar1973Man]

Wire end to end should be 0 to 5 ohm max.

 

Wire to ground should be infinite.

 

Test for 5V with the key on at the sensor plug.

 

Then I would replace the sensor.

 

If still not right then I would send the ECM for testing.