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Ask -Brad- Your Own Question
-Brad-
-Brad-, Dodge Dealership Tech
Category: Dodge
Satisfied Customers: 6971
Experience:  16 Yrs Chrysler/Dodge Technician. ASE Master Certified(L-1)
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I have a 2000 dakota with the 4.7 it cranks but will not

Customer Question

hi i have a 2000 dakota with the 4.7 it cranks but will not start. i have no spark and i am trying to find the my problem. thanks
Submitted: 11 months ago.
Category: Dodge
Expert:  Tim Mohr replied 11 months ago.

Hi, my name is ***** ***** you have a test light or a volt meter? I can help you diagnose this?

Customer: replied 11 months ago.

Yes I have my test light and meter

Customer: replied 11 months ago.
Relist: Other.
Haven't had a response since 12-31-2015
Expert:  -Brad- replied 11 months ago.

Do you need help with this?

Customer: replied 11 months ago.
i do
Expert:  -Brad- replied 11 months ago.

Ok to begin with do you know what P codes are set in the PCM? Most of the time no spark is a result of a bad crankshaft sensor which there should be a code for.. The coil should have a constant 12v on the green/orange wire, and a ground pulse from the PCM on the other.. You will need to test for a ground pulse by connecting the test light to positive battery and probe the wire when cranking which should cause the light to flash..

Keep me posted,

Brad

Customer: replied 11 months ago.
I attempted to check for codes last week but my code reader kept saying fail...i will do some more checking Injust a little while....also not to change the way you want to go about checking but I have seen the no bus message and I have not seen any operation of my gauges.
Expert:  -Brad- replied 11 months ago.

Thanks for the heads up on the "No Bus" which could be why you don't have any spark or communication.. The BUS is the 2 wires all the modules use to communicate and the best way to go about checking this is with a DRBIII scantool I use here at the dealership.. But most likely you don't have one so you will need to start by disconnecting modules until your gauges and scantool communication comes back... And by modules I would disconnect the PCM, TCM, radio, cluster, ABS, Airbag, etc..

Keep me posted on what you find,

Brad

Customer: replied 11 months ago.
We're is the tcm located?? I have heard the owner say it feels like it doesn't start out in first gear more like 3 at times
Expert:  -Brad- replied 11 months ago.

The TCM is located under the hood, if you will look at the air filter housing and directly to the front mounted near the radiator will be the TCM.

Customer: replied 11 months ago.
Ok I checked and I don't have voltage or the ground pulse on the two coils I checked ... the no bus is present going to start unplugging modules
Expert:  -Brad- replied 11 months ago.

Let me know what you find.

Customer: replied 11 months ago.
Are there many common no bus issues
Expert:  -Brad- replied 11 months ago.

Yes we have many BUS issues..

Case Number999925508

Vehicle IssueNO BUS flashes in odometer => Check for 5 volt circuit short to ground or loose ground at pcm...;What is the problem with the instrument panel/cluster? >> odometer In what area is the electrical problem? >> Cluster Have you checked for 5 volt circuit short to ground and loose PCM ground circuits? >> NO What is the problem with the odometer? >> "No Bus" in odometer

System or ComponentCustomer Concern (No DTCs);Instrument Panel / Cluster,Odometer

RecommendationCheck for 5 volt circuit short to ground or loose ground at pcm... The root cause is usually one of the two 5 volt supplies shorted to ground. If so, this will lock up the PCM and you will experience a die out, NO BUS, and a NO RESPONSE problem. The PCM will put out 5 volts on pin a17 (k7) and pin b31 (k6) when the PCM is powered up. See page 8w-80-59 of the 2000 XJ Service Manual, check pins 2 & 22 (power) and pins 31 &32 (ground). if ok then back probe pin 17 (5v) and pin 31 (c2-5v also). If there is no voltage coming out of these drivers, remove the wire and then probe the pin, if the voltage is 4.5 - 5.0 volts then the circuit is grounded, usually it ends of being a shorted crank sensor. As far as the SCI, see page 8w-80-61, the sci transmit will have 12 or 5 volts sent from the DRB3 when accessing the PCM, the SCI receive will have 5 or 12 volts on it just when the key is turned on. the pcm supplies the voltage on the SCI receive, the drb3 supplies the voltage on the SCI Transmit. Its unlikely, but there have been cases where the sci was shorted to VOLTAGE causing the PCM to lock up.

Case Number912320630

Vehicle IssueThe MIL lamp is on, possible "NO BUS" in the odometer. When trying to access the PCM (jtec), there is a NO RESPONSE message displayed on the drb3. You may or may not have a driveability concern. ALL JTEC (1996-2005) EQUIPPED vehicles.;This case not to be confused with the many other cases that pertain to actual driveability/powertrain issues like a hard start, die-out, misfire, programming vin, or a speed control that drops out. You are simply trying to access the PCM to diagnose the problem and the drb3 will not communicate with the PCM only. This case applies to ALL jeeps/trucks/cars (viper) that use a JTEC. This is not to be confused with an NGC equipped vehicle, though the concepts apply, the PCM pin numbers are different. The "NO BUS" or a flashing ODOMETER will appear on all the vehicles that have a digital ODOMETER readout.

System or ComponentProgramming Issue,Engine Performance,Starting Issues;Customer Concern (No DTCs),No Response;JTEC;Engine Compartment;Yes - Intermittent,Yes - Continuously;Start Counter Equal to Zero

RecommendationIn order to communicate with the PCM you only need to have POWER, GROUND, & SCI. Also the 5 volt supplies must not be shorted. There are 3 JTEC connectors, connector A is connector C1, connector B is connector C2, and connector C is connector C3. You want to verify if the vehicle ever stalled out while driving, if so this may help in diagnosing the problem. If either one of the 5 v (pin a17, b31) supplies short out it WILL cause a DIE-OUT condition, unless the truck has a DIESEL engine. The same is true if you lost the B+ (pin a22), ignition + feed (pin a2), grounds (pins a31 & a32). The SCI wires (pins c27 & c29) will not cause a DIE OUT if shorted to ground or open, if either SCI wire is shorted to VOLTAGE is may cause a DIE OUT, this has been reported but not verified, but the short to voltage condition is extremely unlikely. Usually in most Die-out/No Response cases the Crank sensor (a17) or Transmission Temperature sensor (b31)shorts out its 5 volt supply, keep in mind it could be any one of the sensors/wiring, also the amount of sensors may vary depending the vehicle. You will always have the MAP, TPS, CRANK, & CAM sensors. You will need to use the book and verify ALL the SENSORS that are connected to the 5 VOLT supply. If the problem is intermittent, then check for any DTC's in the PCM, if either 5 volt supply was shorted it will not only cause a DIE OUT but it will reset the ignition counts back to ZERO, if the short is present you will have a NO RESPONSE from the PCM. Check the main ground for the PCM, check to see if any engine work has been performed, if so then the GROUND is suspect as well. Use a test light to checkl all the POWERS and GROUNDS. Having a short on the 5 volt supply will essentially LOCK up the pcm and reset it once short is gone. There will be NO CODES. If the problem is current then use a dvom to check the 5 volt supplies, simply back probe PCM pins a17 & b31. If the voltage is less than 4.2 volts then either cut or remove the wire(s), then probe the pin again, if the voltage returns to normal (above 4.2 v) then this is the ciruit that has the short. Leave the DVOM connected while unplugging the sensors or wiring connectors. Once the voltage returns,you have found the short.

Modification Date11/08/04 11:24 AM

Case Number999925386

Vehicle IssueNO BUS flashes in odometer => Check ABS module connector for water intrusion...;What is the problem with the instrument panel/cluster? >> odometer In what area is the electrical problem? >> Cluster Have you checked for 5 volt circuit short to ground and loose PCM ground circuits? >> YES What is the problem with the odometer? >> "No Bus" in odometer

System or ComponentCustomer Concern (No DTCs);Instrument Panel / Cluster,Odometer

RecommendationCheck ABS module connector for water intrusion... If there is water in the module and connector, dry with shop air, clean with electrical contact cleaner, seal with dielectric grease. If water has intruded into the module itself replacement is recommended. Note: Additional symptoms may include: all warning lamps and headlamps stay on. multiple fault codes present in pcm, tcm, abs, acm and fcm. "Messages not received", ."no cluster", and "abs mismatched vin" will be among the messages

Case Number915324355

Vehicle IssueThe gauges intermittently drop out, there are multiple ccd bus codes in mostly every module. The MIL lamp comes on. The odometer either flashes the mileage or reads NO BUS. 1997-2000 AN, 1998-2000 DN.;You need to identify if this is a total ccd bus failure or if truely only the PCM is inactive on the ccd bus, or if its only the CLUSTER dropping out. Usually you can tell this by all the code recorded in the modules. If there are multiple codes that relate to more than one module, then usually the problem is a CCD bus corruption. This case applies to the 1998-2000 DN's, and 1997-2000 AN's. The 2001 AN & DN had a change in the communication system and wiring.

System or ComponentErratic Operation / Fluctuates,Inoperative;08-05-00;Customer Concern (No DTCs),DTC / Error Message;Gauges;Interior;Yes - Intermittent,Yes - Continuously,No - Condition Never Duplicated

RecommendationThe two main areas of concern are either the JOINT CONNECTOR #3 located undert the dash, or Connector C200, it as well is locate in the side knee blocker area. Also check the PCM ground 107. The Durango's had an issue where the auxillary electric water pump (for the rear heat) would leak and inturn get coolant into the harness conduit and cross many circuits at connector C200. There is a tsb for the 1999 AN & DN's for a faulty connecter. This tsb 08-05-00 only applies to the 1999's.

Modification Date06/24/04 9:41 AM

Without a DRBIII you need to start disconnecting modules until the gauges come back..

Customer: replied 11 months ago.
I have the 5v. At pin 17 , 9v at pin 2 ,10v at 22, and ground on both 31 and 32
Expert:  -Brad- replied 11 months ago.

Is the battery fully charged? I would start disconnecting modules to see if the gauges come back..

Customer: replied 11 months ago.
No the battery is not fully charged at this point. I have unplugged the tcm pcm abs radio and cluster I will do some more looking tomorrow afternoon. A couple of the gauges move very slightly . If there was a problem between the crank sensor and pcm would that cause the no bus issue
Expert:  -Brad- replied 11 months ago.

If the crank sensor was shorted you wouldn't have 5v. If you saw the gauges move then your getting close and I would keep disconnecting modules until they come back.. I attached a picture to help..

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