Car

Ask a Mechanic Online and Get Answers to Your Car Questions

Ask an Expert,
Get an Answer ASAP!

Car
This answer was rated:

2000 jeep grand cherokee: gauge..14 v or over ecm..injectors..chrysler

ok i have a 2000...
ok i have a 2000 jeep grand cherokee at my shop with the 4.0 the batt gauge stays at 9 volts and the batt is fully charged it runs but poorly ive checked all the powers and grounds at the pcm all is ok ive even replaced the ecm no luck on my scanner there are no codes and battery voltage reads 0 while running voltage at the batt is 14 v or over ecm is commanding alt to full field and injectors wide open to compensate for the low voltage and yes 2 scanners communicate and have basically the same readings otc/snap on ive tried to find wiring diagrams from the amp gauge out but every thing is very vage even on the chrysler site ive also diconnected every sensor on the engine looking for a pull down but no luck there either        HELP!!!!!!!!!!    thanks ken
Show More
Show Less
Ask Your Own Car Question
Answered in 39 minutes by:
2/26/2008
Donny
Donny, ASE Certified Technician
Category: Car
Satisfied Customers: 828
Experience: A.S.E. Master Technician, Over 25 years working in Chrysler dealers, Top tech DaimlerChrysler 1998
Verified

Hello

The Jeep does not truly have an Amp gauge or true Voltmeter, all the information like that is sent over the PCI BUS to the cluster from the PCM if the PCM is reading zero volts the 9 is most likely just a place keeper for the cluster,

From what you are describing you have lost battery sense to the pcm, you will need to check pin 25 in the c3 PCM connector(light blue with red wire) for voltage while running back probe should be what the battery is reading this is the gray 32 way connector, also you will need to check pins 2 (orange with dark blue) and 22 (red with black) in the c1 connector at the pcm black 32 way if any of these do not read battery voltage you will need to back trace the wire for a break or large amounts of corrosion

Check around the PCM and its mounting where all the different connectors are

I hope this helps and gets you on your way

If you need more information just let me know

Thank you

Donny

Donny
Donny, ASE Certified Technician
Category: Car
Satisfied Customers: 828
Experience: A.S.E. Master Technician, Over 25 years working in Chrysler dealers, Top tech DaimlerChrysler 1998
Verified
Donny and 87 other Car Specialists are ready to help you
Ask your own question now
Customer reply replied 9 years ago
hi thanks but i have already checked those voltages and everything is ok i have even run a jumper backprobing to 12v on each of those wires and still no voltage

Hi

So you overlaid your own wires and it is still full fielding the alt?

Have you run the no fault charging diagnostic tree?

Possible causes

B (+) CIRCUIT HIGH RESISTANCE

GENERATOR GROUND HIGH RESISTANCE

B(+) CIRCUIT HIGH RESISTANCE (1.0 VOLT)

GENERATOR BELT OBSERVABLE PROBLEM

GENERATOR FIELD TERMINAL INTERMITTENT PROBLEM

TROUBLE CODES PRESENT

TROUBLE CODES PRESENT 2000 RPM

PCM (CHARGING SYSTEM NO CODE)

1 Turn ignition off.

Note: Battery condition must be verified prior to this test.

Inspect the Generator Belt tension and condition.

Is the Generator Belt OK?

Yes Go To 2

No Repair as necessary.

2 Start the Engine.

Turn on all accessories.

Raise engine speed to 2000 RPM for 30 seconds then return to idle.

With the DRB III read DTC's.

Are there any Charging System Trouble Codes?

Yes Refer to SympXXXXX XXXXXst for problems related to Charging.

No Go To 3

3 Ignition On, Engine Not Running

With the DRB, actuate the Generator Field.

Using a 12-volt test light, backprobe the Generator Field Driver Terminal at the back

of the Generator.

Note: The test light should blink On and Off every 1.4 seconds.

While monitoring the 12-volt test light, wiggle the Field Terminals back to the PCM

and ASD Relay.

Was there any interruption in the normal cycle of the test light?

Yes Repair the wire where wiggling interrupted the voltage cycle.

No Go To 4

4 ignition On, Engine Not Running

With the DRB, read trouble codes.

Are there any charging Systems trouble codes?

Yes Refer to SympXXXXX XXXXXst for problems related to Charging.

No Go To 5

5 Turn ignition on, engine not running.

Using a Voltmeter, measure voltage between the Generator B(+) Terminal and the

Battery (+) Post

Caution: Ensure all wires are clear of the engine's moving parts.

Start engine.

Is the voltage above 0.4 volt?

Yes Repair the B(+) Circuit for high resistance between the Generator

and Battery.

No Go To 6

6 Start engine.

Warm the engine to operating temperature.

Caution: Ensure all wires are clear of the engine's moving parts.

Using a Voltmeter, measure voltage between the Generator case and Battery (-) Post.

Is the voltage above 0.1 volt?

Yes Repair Generator Ground for high resistance, Generator Case to

Battery (-) side.

No Go To 7

7 Ignition On, Engine Not Running.

With the DRB, read the Battery voltage and record the results.

Using a Voltmeter, measure Battery voltage B(+) to B(-) Terminal and record the

results.

Compare the two voltage readings.

Is the voltage difference less than one volt?

Yes Test Complete.

No Go To 8

8 Ignition On, Engine Not Running

With the DRB, read the Battery voltage and record the results.

Turn Ignition off.

Disconnect the PCM.

Note: Check connectors - Clean/repair as necessary.

Turn Ignition on, with the engine off.

Using a Voltmeter, measure the Fused B(+) at PCM Connector.

Is the voltage within one volt of the DRB recorded reading?

Yes Go To 9

No Repair the B(+) Circuit for high resistance between the PCM and

the Battery.

9 if there are no possible causes remaining, replace the Powertrain Control Module.

View repair options.

Repair

Replace the PCM.

I dont think you will need nine as you already tried it, the only other thing I can think of is the crank sensor,I have seen gauge issues and charging issues caused by these even though the car runs

Donny

 

Ask Your Own Car Question
Customer reply replied 9 years ago
hi donny day 3 still no sucsess all new cam crank and coil pack ive disconnected every sensor on the truck i think i want to try another computer again i am going to try a used one this time if i plug a used computer from a dakota in the gauge works fine but wount start for obvious reasons the computer i recieved from the dealer says it needs to be programmed which we havent had done but the gauge should still come up even though its not programed right? one difference with these new parts is it does run better now it starts right up but still doesnt run right on start up it sounds like it has a big race cam then smooths out

Hello

Be careful swapping computers around since if one car has vehicle theft and the other one does not, if you put the one that does not into the car that does it can learn the theft system and then when you put it back in the car that does not it will not work and will need to be replaced it can also teach a Body controller theft and that may also need to be replaced

If the Jeep you are working on has a chip key, then you have to have it programed as soon as you install it all the secret key information has to be moved from the security module into the engine control module and keys may need to be reprogramed or replaced,if you install it but do not turn the key to the start position all the gauges, etc. should work, if you cycle the key too many times you will lock the controllers down, any more then 2 key cycles can cause it to lock out, so if you try it you will need to unplug it and either put the original back in to drive it to have it programmed, or leave it unpluged and tow it and have them plug it back in too program it, if no chip key or alarm you can install it and drive it over so they can put in the VIN and mileage

Have you run a cluster self diagnostic, I know that with a DRB3 you can force the cluster to run a self test which would tell you if it was having any internal or communication issues, I am not sure if you can do this or not with your test equipment

Try this and watch the gauge for a full sweep if you cant run a self test with your scanner

1. With the ignition switch in the off position, depress and hold the odometer-reset button.

2. Turn the ignition switch to the run position, continue holding the odometer reset button until the cluster needles start to move, then release the reset-button. (Do not allow the ignition switch to enter the start position) The gauge needles will sweep in both directions and come to rest in the correct position relative to the stop peg.

This will at least tell us if the cluster is capable of displaying higher then 9 v

Let me know what happens and if you need more information

Donny

Ask Your Own Car Question
Customer reply replied 9 years ago
hi yes i have done the cluster diag and all the gauges do sweep including the amp gauge the computer i was using was one we had as a test dummy so there was no other vehicle involved   i believe the cluster is ok when i put the ecm from the dodge truck in to see if the gauge came up it did and read batt voltage

Hello

Well after having checked and verified all the wiring and connections like you have done and seeing the cluster be able to display more then 9 volts, I would say that it most likely is the engine controller, the only thing you may want to do first is verify the controller grounds by putting them under load, i normally do this by using a light bulb (fog lamp bulb) hook a jumper wire up to B + and then to one side of the bulb and then hook the other side of the bulb to the ground pins of the engine controller connector one at a time and be sure the bulb is bright, some times an ohm meter can show good continuity to ground but when current is flowing the ground is not good, if this tests fine then the controller is most likely bad

Pins 31black with white and 32 black with tan of the c1 black connector

If you need more information just let me know

Thank you

Donny

Ask Your Own Car Question
Customer reply replied 9 years ago
hi don thanks for all your info i have a yard computer comming tommorow i will try that and let you know how i make out youve been great thanks ken

Hello

If by yard computer you mean a used computer from a salvage yard, it will not run the Jeep if the Jeep has the chip key or factory theft system, once the computer is programed with the VIN it cant be overwritten or changed to a different vin, if the Jeep you have does not have one or both of these systems on it you should be able to use it,

Donny

Ask Your Own Car Question
Customer reply replied 9 years ago
hi don ok the used computer did the trick the gauge comes up now and the truck runs for a few seconds before the sec system shuts it down but when it does run it runs normal i ordered another reman one from chrysler then i will have it programed

Hello

Thats good to hear, then you should be all set once the reman is programed to the jeep

Take care

Donny

Ask Your Own Car Question
Ask Donny Your Own Question
Donny
Donny
Donny, ASE Certified Technician
Category: Car
Satisfied Customers: 828
828 Satisfied Customers
Experience: A.S.E. Master Technician, Over 25 years working in Chrysler dealers, Top tech DaimlerChrysler 1998

Donny is online now

A new question is answered every 9 seconds

How JustAnswer works:

  • Ask an ExpertExperts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional AnswerVia email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction GuaranteeRate the answer you receive.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

I would (and have) recommend your site to others I was quite satisfied with the quality of the information received, the professional with whom I interacted, and the quick response time. Thanks, and be sure that I'll be back whenever I need a question answered in a hurry.

Stephanie PElm City, NC

used your service this weekend with "Trecers" help. thank you ,thank you, thank you. replaced an A/C fan motor. Local Auto Zone had part. $15.00 "tracer" fee and $40.00 for parts, I saved several hundreds of dollers at a shop. i will recommend you and use you in the future.

David L.Richmond, TX

9 dollars, 2 hours of my time, and I drove away. Your diagnosis was right on the mark. Thank you so much.

PhilMarysville, CA

Lurch. Thank you very much. I had real doubts about this website but your promptness of response, quick followup and to the point answer with picture was incredible.

CharlesWalnut Creek, CA

As a single woman, I really appreciate an excellent and affordable opinion.
Thank you Geordie, I will not hesitate to contact justanswer in the future!

SueCharleston, WV

Another great insight to what may be the problem. I will have my mechanic take a look at it tomorrow. Thanks again, Frank...you do indeed know your stuff.

JimCastleberry, FL

The nearest Volvo dealer is 160 miles away. Best $15 bucks I have spent in a long time!

Paul MCorpus Christi, TX

< Previous | Next >

Meet the Experts:

Chris (aka-Moose)

Chris (aka-Moose)

Technician

1,212 satisfied customers

16 years of experience

Ted G.

Ted G.

ASE Certified Technician

1,708 satisfied customers

20 years auto repair experience, ASE Master Tech, Mechanical Failure consultant, Expert Witness

George H.

George H.

ASE Certified Technician

1,522 satisfied customers

ASE Master Tech 15+ yrs, AAS Automotive Technology, Factory trained Asian specialist

GM Tech (Cam)

GM Tech (Cam)

Auto Service Tech

669 satisfied customers

GM Grand Master Technician 2007. 14 years experience.

Amedee

Amedee

Former ASE Master Tech

2,505 satisfied customers

ASE certified tech advanced level specialist. Wisconsin certified emissions state inspector

Jerry

Jerry

Master Mechanic

2,181 satisfied customers

ASE master, 30+ years. All makes and models. Trouble shooter, shop forman, service manager

Richard

Richard

ASE Certified Technician

1,000 satisfied customers

12 years Ford Lincoln/Mercury Jaguar dealership as a technician and shop foreman reparing all makes

< Previous | Next >

Related Car Questions
My mini is throwing code p0012 and the oil light comes on
my mini is throwing code p0012 and the oil light comes on and goes off … read more
David Craig
David Craig
OWNER/MECHANIC
Associates
3,931 satisfied customers
V.w.2003 passet 6 cil. when car is cold i can disconnect
v.w.2003 passet 6 cil. when car is cold i can disconnect positive cable when car warms up battery light comes on and car no longer charges … read more
vwtech0405
vwtech0405
VW Technician
Associate Degree
8,868 satisfied customers
2008 Silverado 3500 HD 6.6 so I installed the turbo and
Hey Michael : 2008 Silverado 3500 HD 6.6 so I installed the turbo and inner cooler also so I was looking at the TPS and the plastic cover cracked on it I'm going to replace it so dealer sells it with … read more
Michael Solis
Michael Solis
252 satisfied customers
Actually my question is for a radio I bought at a junk yard
Actually my question is for a radio I bought at a junk yard that came out of a 2004 Audi Allroad, trying to find the radio code for it? … read more
sprinkles08
sprinkles08
Technician
High School or GED
11 satisfied customers
My sons 2003 9-3 convertible had the check engine light and
My sons 2003 9-3 convertible had the check engine light and traction control light come on immediately after getting gas. The code reader showed P1264 - I cleared the code and took it for a 3 mile rid… read more
Curtis
Curtis
Vocational, Technical or Trade Scho
1,672 satisfied customers
2017 GMC Acadia slt-1. I'm trying to disconnect the Onstar
Hello Pearl JA: What is the model/year of your GMC? Customer: 2017 GMC Acadia slt-1 JA: Are you fixing your Acadia yourself? What have you tried so far? Customer: Yes. I'm trying to disconnect the Ons… read more
Michael Solis
Michael Solis
252 satisfied customers
My 04 Suzuki Vitara lx v6 my 4x4 not working. I've tried
my 04 Suzuki Vitara lx v6 my 4x4 not working JA: Are you fixing your Vitara yourself? What have you tried so far? Customer: i've tried checking the tranfser case JA: Anything else you want the mechani… read more
indy-tech
indy-tech
Shop owner, technician
Vocational, Technical or Trade Scho
11 satisfied customers
I. Cooling system dumps out water after car has run when it
Cooling system dumps out water after car has run when it has stopped … read more
Mechanic01
Mechanic01
1,151 satisfied customers
My is a pacifica 2004, the battery died and we tried to jump
hello, my is a pacifica 2004, the battery died and we tried to jump up with another car, and it work but 2 days later it started to fail the lights, the transmission and we couldn't drive more the 30m… read more
Curtis
Curtis
Vocational, Technical or Trade Scho
1,672 satisfied customers
I need an explosion diagram showing the location of the fuel
I need an explosion diagram showing the location of the fuel pressure regulator for a 2001 GTMC Jimmy 4.3L and a picture of the regulator.… read more
Carhelp4u
Carhelp4u
GM Service Training
2,560 satisfied customers
Need to change the battery. Which cable goes first?
Need to change the battery. Which cable goes first? … read more
3pac2222
3pac2222
nissan master auto tech
Associate Degree
2 satisfied customers
I own a 2001 q3 convertible that doesn't always start. What
I own a 2001 q3 convertible that doesn't always start. What could be wrong? … read more
indy-tech
indy-tech
Shop owner, technician
Vocational, Technical or Trade Scho
11 satisfied customers
I have a 2008 GMC Acadia the car won't turn off here's the
Good afternoon good afternoon I have a 2008 GMC Acadia the car won't turn off here's the situation turn on the card fine and you go to turn it off and it stays idling you have to turn it back on turn … read more
Chris (aka-Moose)
Chris (aka-Moose)
Technician
Vocational, Technical or Trade School
1,212 satisfied customers
I have been told that I should never try to jump start my
I have been told that I should never try to jump start my 2004 BMW 745i if the battery is dead or I WOULD RISK BURNING OUT THE COMPUTER THAT OPERATES THE BATTERY. iS THIS CORRECT?… read more
Dan
Dan
Automotive Technician
Vocational, Technical or Trade Scho
25 satisfied customers
I saw the brake light indicator on my 2005 lexus es330. the
Hi. I saw the brake light indicator on my 2005 lexus es330. the bulb was out on the trunk brake light. I changed it. The indicator is still on. Now what? Wiring? … read more
baddad1
baddad1
technician
High School or GED
5 satisfied customers
The door actuator on our 2013 450h passenger front side quit
The door actuator on our 2013 450h passenger front side quit working and now the door won't unlock. I need to unlock the door to replace the actuator. … read more
Peter Bagley
Peter Bagley
master technition
Vocational, Technical or Trade School
908 satisfied customers
Not really my car but just wonder for a car I might buy.
Not really my car but just wonder for a car I might buy … read more
George H.
George H.
ASE Certified Technician
Associate Degree
1,522 satisfied customers
Airmatice w211 issues. 2003 e320 sport the front is up but
2003 e320 sport the front is up but the rear is down … read more
Todd M
Todd M
Owner
ASE Certification
1,287 satisfied customers
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Show MoreShow Less

Ask Your Question

x