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ECM failure or wiring issue?

Shmokes24v
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Shmokes24v

Shmokes24v

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OK I'll start with my truck is a 99 24v auto. All stock aside from a beans sump and a fass 150. I had a edge ez but it's been removed. Also I just replaced the vp44 with a used vp44. Before I replaced it I had a hard set p1689 no communication between ecm and vp44. Once I put the replacement VP in the code immediately went away and right before I had all the injectors bled(almost had it running) it threw the p1694 in both ECM and PCM and then kicked me out of the bus connection. Still have power at the data link connector. 

Now I'm unable to connect my scanner(Autel Maxidas) to either, no tach signal while cranking, no wait to start light, no lift pump signal, and pin 7 on the vp44 isn't getting power. Likely because the fuel pump relay isnt getting the correct signal. If we put power to the wire from the FP relay that goes to pin 7 on the vp44 we can hear the VP click on. I've tested all fuses and grounds with my power probe 3 and all test good. I pulled the ECM plug and tested all the pins and it's getting correct power and ground from pins 48,49,50. I did notice all pins related to Cummins bus showed no signal or anything on the power probe. Pins 40 and 41 show 0.0 with key off and a little over 2v with key on. I may be making this harder than it should be but I'd like to rule out any other possibilities before replacing the ECM... Any help is greatly appreciated.

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Shmokes24v

Shmokes24v

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Just got home, cleaned the ground on the inside of the cab under the drivers kick panel area. Plugged the ECM back in and turned the key on and now the WTS light came on and I have codes for all the sensors I unplugged. Gonna scan it to make sure but this is why it's got my puzzled.... 

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Cleared out the codes and these are the only 2 that came back because these sensors are unplugged. Not sure why the coolant temp sensor has too high of voltage when it's unplugged...

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Shmokes24v

Shmokes24v

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The coolant temp sensor I believe is shorting to ground. Using the power probe ect3000 I plugged it into the blue wire and it immediately sounded the tone and lit up the light "short"...

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Well I put it in the ground pin on the map sensor and the cam sensor and they are all shorting. And with the tracer device I got the strongest signal of the short from the big cluster of wires under the ECM. Guess I'll open up the harness there and see what I can find. Looks like it's already been taped up by someone else.

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dripley

dripley

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When my ECM went I got a lot high and low voltage codes, but I also how very high ECT readings on cold start and the engine would idle but the RPM's were all over. Touch the throttle and they would build so much I would have to shut the engine down. I hoping yours is just the wiring.

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Shmokes24v

Shmokes24v

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2 hours ago, dripley said:

When my ECM went I got a lot high and low voltage codes, but I also how very high ECT readings on cold start and the engine would idle but the RPM's were all over. Touch the throttle and they would build so much I would have to shut the engine down. I hoping yours is just the wiring.

 

My map and ECT were unplugged that's the reason for the codes. Just not sure now why my APPS is showing 160volts

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Me78569

Me78569

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Well keep in mind that PID Standards aren't always standard when they come through the SCI bus.  

 

I would test your apps output and see what voltage it actually is.  Your 160 v might actually be showing that the sensor is reporting x voltage, but the IVS is triggered.   

 

 

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Shmokes24v

Shmokes24v

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Well I got the new oil pressure sending unit installed. The new one was much smaller than the one I removed but it threaded into the block fine. I guess my batteries were too weak because when I went to start it the grid heater kicked on and turned off every light on the dash and then it didn't want to act right.  So I unhooked the grid heater power wire from the battery and tried again but the WTS light wouldn't come on even after I had my TDI charging the batteries... So I got frustrated thinking this replacement vp44 was bad because I had 2 hard codes in the pcm saying no communication. I used my power probe in the PDC and put power to the pin under the fuel pump relay and tried starting and sure enough it fired right up. Turned it off and replaced the relay and now it's been starting no problem from the key... Haven't the slightest idea what's going on but I also have the grid heater and my abs unplugged. Went out this morning and it fired up no problem.... very confusing. After it started I was able to clear the codes and nothing's come back yet.

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