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P0341..Rough Idle...Smooths Out...Lose Tach


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Ok, so. I have read about the P0341 and possible solutions. Now the back story is that this truck had several faults and I was able to remedy 90% of them. 
 

It had P01689 & P01688..P01689 I believe is due to 56mVAC coming from my alternator. When I disconnected the alt. charge cable the fault went away.

The P01688...had to replace the VP44.

 

It also had P0222, which still comes up randomly, adjusted the voltage to .465VDC and APPS relearn and it is doing better.

 

I keep getting P0341, it stumbles and idles rough then, it clears up and when it does clear up my tach quits working.

 

So, I checked the wiring on both the cam and crank sensors. They all ohm out good and I am getting 5.05-5.0VDC while, utilizing the sensor ground and then the chassis ground. 
 

I’m gonna recheck some things tomorrow, but I thought I’d post a video so y’all can see what it’s doing. Any input and advice is greatly appreciated!

 

Merry Christmas Y’all!

 

PS...the screeching noise you hear in the background  is my daughter being silly and is not my truck...LOL

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  • 2 months later...

Ok, so I checked the wiring and it’s good. Now, something I did discover. If I disconnect the crankshaft sensor and start the truck...the tach will work for about 5 seconds then goes away, BUT it doesn’t buck and miss...it idles smooth.

 

I drove it down the driveway like this and when letting out in the clutch slowly, the engine would surge up and down. Just making the loop in the driveway was all I did.

 

Rescanned for faults and had..P0341, P0222 and P1689...🤮

 

P1689 freaked me out!!! So, I plugged the crank sensor back in and cleared the faults. Around the driveway again and no P1689!!

 

So, that brings me to now...so I purchased an Autel MS906BT and captured the freeze frame data. I have attached a photo and I need to know what the Cummins faults are?

 

I also, took a picture of the RPM’s for the VP, cam and crank sensors....is it supposed to be cam sensor (1) or just cam sensor with RPM?

 

I ask because I think it might have the wrong engine ECM.

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Ok, so. I was able to find an actual 99 engine ECM. Installed it and cleared all the previous faults. P0341 and P0122 & P0222.

 

Started the truck and guess what? No surging or bucking. Idle smooth. Took it for a test drive and scanned for faults and now I’m getting P1693 on the PCM and TCM, no other faults between the two. Now I do have an ABS fault and something with the SRS, but will this generate the P1693 or is it just between the Engine ECM and the PCM
 

I think my scan tool is seeing the ECM as PCM and the actual PCM as TCM.

Another note, the P1693 will not go away if I try to erase it. 
 

So, any input will be greatly appreciated. Could be another bad ECM?? It seems to run really well and starts right up.

 

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  • Staff
3 hours ago, Frog said:

Another note, the P1693 will not go away if I try to erase it. 

Mopar's Note's:

This error code cannot exist by itself and will have other error codes present in the ECM and/or PCM you'll most likely require an OBDII scan tool to get the codes. P1693 is nothing more than a flag that is pointing to the other module stating there are errors. If the PCM has the P1693 code this only means that the error codes are on the ECM. Visa-Vera as well. If the ECM reports the P1693 that means the error codes exist on the PCM.  If both report the P1693 code basically both module pointing the finger at each other stating there are errors on both modules. Typically the key trick is the only place this code will show up. I've also seen a few "cheap OBDII code readers" also report this code but doesn't state which module reported. Always best to use a quality OBDII code reader. 

Edited May 2, 2018 by Mopar1973Man 

 

Just a thought, could be the PCM  is not seeing the ABS module.  The PCM  gets the vehicle speed signal, white/orange wire,  from the ABS module but if the code comes on just starting the engine and not moving then no speed signal is generated and the ABS may not be the problem.

Edited by IBMobile
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Thanks guys. P0341 has been corrected with ECM replacement. Now the P1693 is my issue. I believe IBMobile is on to something.

 

I was able to read that ABS fault and it came up with ABS Main Relay Power, or something to that nature. So, maybe the ABS is the culprit?

 

One more thing. When I was viewing live data, it was saying my APPS Voltage was 160.5...is that even possible?

 

I measured the voltage at the APPS and recorded 4.95VDC, while using the ground wire and a good chassis ground.

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  • Owner
On 3/4/2021 at 10:18 PM, Frog said:

IBMobile...huh???

 

Will an ABS fault or SRS fault cause P1693?  Or will it only be active from an Engine ECM or PCM fault?

 

No. P1693 is just a flag code stating the other module has errors. It does not include ABS or SRS code are separate. 

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3 hours ago, Mopar1973Man said:

No. P1693 is just a flag code stating the other module has errors. It does not include ABS or SRS code are separate. 

Ok thanks! So, with it showing up in the TCM and PCM...with no other faults could it be another issue that’s not logging a code? I am using an Autel MS906BT...tried the key trick for retrieving faults and could not get it to work.

 

One thing I did notice while viewing live data...APPS voltage shows 160.54, but no fault for APPS/TPS. Sorry, truck is a 1999 Dodge 2500 24 valve Cummins 5 speed 4x4.

 

Thanks

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  • Owner

Yeah if your using a cheap reader typically they show the P1693 code. Like I'm using a Innova live data and scan tool. It doesn't display any P1693 codes. Just all the other codes. It might be that your tool only sees the PCM but skipping the ECM hence why you see the P1693 code and nothing reported from the ECM.

 

Just remember the PCM is the master and ECM is the secondary computer. You need a quality tool that can read non-OBDII systems. Strange enough these trucks if you look up the PID (1C Hex) for OBDII compliance it will report back a Hexadecimal of 05 meaning it is not OBDII compliant. Strange but true...

 

Screenshot_20210307-072124_Chrome.jpg

Edited by Mopar1973Man
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10 hours ago, Mopar1973Man said:

Yeah if your using a cheap reader typically they show the P1693 code. Like I'm using a Innova live data and scan tool. It doesn't display any P1693 codes. Just all the other codes. It might be that your tool only sees the PCM but skipping the ECM hence why you see the P1693 code and nothing reported from the ECM.

 

Just remember the PCM is the master and ECM is the secondary computer. You need a quality tool that can read non-OBDII systems. Strange enough these trucks if you look up the PID (1C Hex) for OBDII compliance it will report back a Hexadecimal of 05 meaning it is not OBDII compliant. Strange but true...

 

Screenshot_20210307-072124_Chrome.jpg

Well, let’s hope my Autel MS906BT is capable and I believe it is. I have attached a fault code report and also a live data sheet. 
 

The odd thing to me is the AAPS voltage of 160.50VDC... I’ll attach a video too.

 

 

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The wait to start light is the only thing that will make it fluctuate.

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Guess I should clarify. I was doing a wait to start light test. It cycles it on and off, while doing so, the apps voltage fluctuates slightly. This is the only thing I have found that effects the voltage reading for the APPS

 

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