How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Juan Crespo Your Own Question
Juan Crespo
Juan Crespo, ASE Certified Technician
Category: Dodge
Satisfied Customers: 1522
Experience:  A.S.E. Master Technician, Advanced Level, Emissions - Asian, Domestic, & European
19298667
Type Your Dodge Question Here...
Juan Crespo is online now
A new question is answered every 9 seconds

MY NAME IS ***** *****. IF YOU CAN SEE THE SAME ARTICLE THAT

Customer Question

Customer: HI. MY NAME IS ***** *****. IF YOU CAN SEE THE SAME ARTICLE THAT IM SEEING IM HAVING THE SAME SITUATION. WELL FIRST LET ME KNOW HOW YOU CHARGE PLEASE
JA: Thanks. Can you give me any more details about your issue?
Customer: 02' DODGE DAKOTA 4.7 ENGINE. I'VE SEEN THE TRUCK RUNNING TWO TIMES BUT WHEN IT FAILS IT TURNS OVER BUT DOSE NOT RUN, NO BUS SIGN ON THE CLUSTER SCREEN, I HAVE COMMUNICATION WITH MY SCANNER THE FIRST TIME THERE WAS A CODE ABOUT ENGINE SPEED INPUT CIRCUIT P0725. I DID A LOT OF TESTING IF YOU WANT I CAN EXPLAIN WHAT I DID.
JA: OK got it. Last thing — JustAnswer charges a fee (generally around $18) to post your type of question to Dodge Experts (you only pay if satisfied). There are a couple customers ahead of you. Are you willing to wait a bit?
Customer: OK
JA: OK. Now I'm going to take you to a page to place a secure deposit with JustAnswer. Don't worry, this chat is saved. After that, we will finish helping you.
Submitted: 1 year ago.
Category: Dodge
Expert:  Juan Crespo replied 1 year ago.

Hi there. Thank you for using our service.

PCI BUS is a single wire communication format that allowed electronic modules to share data. Things that can bring it down are ground or power issues with any of the modules on the BUS, or with any of the sensors that receive a 5 volt signal from the PCM.

As you probably know by now, this issue is not easy to diagnose without the aid of a DRBIII scan tool. Basically, you'd need to unplug every module and sensor one at a time unitl the culprit was found. However, since you mention a previous trans code, I would strongly advice you to do the following first:

  • Disconnect both battery cables for at least 5 minutes
  • Disconnect the trans control module (TCM) - leave disconnected
  • Reconnect battery cables
  • Turn ignition on and check for normal odometer operation

If the NO BUS message is now gone, the issue lies with either a bad connection at the TCM, or a bad TCM itself.

Please let me know how it goes. Best Regards.

Customer: replied 1 year ago.
I DID THAT ALREADY DOES THE SAME THING. I PUT BOTH CABLES TOGETHER FOR 5 MIN PLUG IT BACK AND TRY WITH THE KEY ON "NO BUS" ON THE CLUSTER AND IF YOU TRY CRANKS BUT DOSE NOT START I DID A LOT OF TESTING IF YOU WANT I CAN EXPLAIN TO YOU. THANKS
Customer: replied 1 year ago.
I GOT SOME INFO FOR YOU: I DID CHECK REF VOLTAGE: 5.47 VOLTS @ 12.68 VOLTS OF BATTERY VOLTAGE. I DID CHECK WITH A NEW CRANK AND CAM SENSORS ONE AT A TIME AND THERE WAS NO DIFERENCE. WILE I WAS UNPLUG IN SENSORS I CHECK THE CLUSTER LOOKING FOR THE NO BUS LEGEND BUT DID NOT APPEAR SO I CRANK THE TRUCK AND RUN - CUT OFF IN 10 MIN. I HAD A REMAN PCM AT HAND REPLACE IT AND THE TRUCK WORKS - CUT OFF IN 5 MIN. LET ME KNOW IF YOU HAVE ANY IDEA THANKS.
Expert:  Juan Crespo replied 1 year ago.

Happy New Year and thank you for the update.

Actually, 5.48 volts is quite high, it should be no more than 5.0 volts. Are you reading that voltage directly from the harness with a voltmeter, or seeing it displayed on a scan tool screen?

Also, any reason why you did not disconnect the TCM as I had suggested?

Lastly, you state "it cuts off". I need to know what cuts off: is it spark?, injector pulse?, fuel pressure?, power to the PCM? Power from the PCM to the ASD relay?

Customer: replied 1 year ago.
Sorry! I WAS VERY BUSY. Ok I DID UNPLUG THE TCM TO DO WHAT YOU ASK ME TO DO, NO CHANGE AT ALL. WELL I DID TEST THE 5VOLT SUPPLY BETWEEN ORG AND BLK/LTBLU FROM THE TPS. YOU SAID THAT IS TO HIGH. DO YOU HAVE ANY OTHER SUGGESTIONS. THANK'S
Customer: replied 1 year ago.
WHEN THE TRUCK CUTS OFF THERE IS NO POWER IN THE AS RELAY. Ok THE PIN 3-C3 ON THE PCM SENDS (-) TO THE PIN 85 OF THE ASD RELAY TO ACTIVATE IT. WHEN THE PROBLEM HAPPENS I REMOVE THE ASD RELAY, WHAT I HAVE ON THE 85 PIN IS 12.08 VOLTS THAT'S WITH MY RED LEAD ON THE BATTERY (+) SIDE AND THE BLACK LEAD ON THE 85 PIN OF THE ASD. THAT DOES NOT MAKE THE RELAY CLICK. IF I TEST WITH A LED TESTER THE LED LITE VERY DIM. I DID TEST THE WIRE FROM PCM TO ASD AND IS GOOD. IF YOU WANT I CAN RATE YOUR JOB NOW LET ME KNOW
Customer: replied 1 year ago.
I DID PUT AN SMALL WIRE TO THE 85 PIN (ASD) AND WHEN I PLUG THE RELAY THE VOLTAJE GOES AWAY, CERO VOLTAGE DOES THE SAME THING WITH THE NEW PCM.
Expert:  Juan Crespo replied 1 year ago.

Your test at pin 85 of the ASD relay indicate the PCM is sending the correct ground signal. The problem could be somewhere else. For example, once the ASD is activated, it sends power to the O2 sensor heaters so if there is a problem with that circuit it can affect the signal the ASD sends back to the PCM.

I hope you understand that this kind of issue is best handled with the help of a DRBIII and a lab scope. Otherwise, all you can do is make sure you have a good PCM that's programmed to the vehicle, then, with the battery disconnected, unplug all the modules and sensors that receive and send a signal from and to the PCM and inspect all those connectors. Once everything is disconnected, reconnect the battery and check the odometer. If the NO BUS message is still there, replace the PCM. If it's gone, reconnect the sensors one by one until one of them makes the NO BUS message reappear. Replace that sensor and keep reconnecting until everything is reconnected back to normal and the NO BUS message is gone.

At this point, you can rate my service if you'd like. Best Regards.