Question about 2004 Jeep Liberty

1 Answer

How to know if pcm is bad

Will not crank no engine light

Posted by on

1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    Top Expert:

    An expert who has finished #1 on the weekly Top 10 Fixya Experts Leaderboard.

    Superstar:

    An expert that got 20 achievements.

    All-Star:

    An expert that got 10 achievements.

  • Jeep Master
  • 21,873 Answers

The PCM would probably not keep the engine from cranking. If the check engine light does not come on when you turn the key switch on, I would check to see if all of the fuses are getting power from the key switch first.
Could be a problem with the key switch.

Posted on Jul 16, 2013

1 Suggested Answer

6ya6ya
  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi,
a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
goodluck!

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

2 Answers

2002 town and country will not start intermittently. Been checked out at garage. Say they cannot find anything. Most times when try to start all warning lights come on.


Will not start how intermittently ? The engine won't turn over or engine does turn but won't start . Starter relay , lose connection . Checking power an grounds would be the first place to start , voltage drop test the main electrical circuits . Voltage Drop Testing the Starter

The starter circuit control is achieved by the starter motor relay ! It is located in the under hood fuse/ relay box or as Chrysler calls it ,integrated power module ! If you pull out the relay an look on the bottom where the pins stick out you will see four sets of numbers .30,87 an 85,86 ! 30 is B+ voltage . 87 is to the starter solenoid . If you jumped those two spots where the relay plugs into the starter would crank the engine over . The last two 85 an 86 are the control side .If you checked with a volt meter where 86 plugged into ,with key on it would show B+ voltage . The last pin is from the PCM - engine computer . When turning the key to start a signal is sent to the PCM to let it know crank has been requested , in return the PCM supplies a ground to pin 85 energizing the starter motor relay sending B+ voltage to the starter motor cranking over the engine . Here is another video on test from the relay base (where relay plugs into ) This is for a horn circuit but same thing . VEHICLE RELAYS Testing from the relay base The relay could be going bad , you never know .Replacing the relay mite not be a bad idea . Good luck , hope this helps !

Jul 23, 2016 | 2002 Chrysler Town & Country

2 Answers

My 2007 Suzuki forenza will turn over good but will not start fuel pump new but when you turn switch on can't hear it hum gas getting to injectors reckon it could be anti theft security please thanks


Is there a SECURITY light lit on the dash ? All anti-theft systems warn you some how if a problem is present ! The fuel pump only comes on for two seconds with key on ! When cranking the engine over if a crank pulse is see by the engine computer it will energize the relay turning on the fuel pump ! You have to check the fuel pump electrical circuit from the fuel pump relay !

Jun 09, 2015 | 2007 Suzuki Forenza

1 Answer

I have no spark on my 1999 chrysler sebring convertable


You will need at least a 12 volt test light to check the cam and crankshaft sensors. If either one is bad, the auto shut down relay will not ground the PCM. Remove the 4 pin electrical connector from the coil. one of the terminals is a 5 volt feed. Connect the light to that terminal and clip the other to ground. Turn the key to the on position. the light should flash once. If it does not flash the problem is in the ASD relay or its circuit. If it flashes once, try to start the engine. (don't worry, it can't start.) See if the light flashes during cranking or not. If not, return the key to off and then disconnect the crank sensor wire connector and try again. If it flashes as you crank the engine now, then the crank sensor is bad. If it does not flash during cranking then the cam sensor is probably bad. They are both easy to access and replace. The PCM could also be bad, but the cam/crank sensors are a more common problem. A repair manual is a cheap investment and could be helpful. Good luck.

Feb 28, 2015 | 1999 Chrysler Sebring LXi

1 Answer

1997 jeep Grand Cherokee Laredo 4.0 4wd. All the gauges dropped and now won't start. I've replaced the computer but still nothing


wont crank or cranks fast but will not start,????????
wow first thing replaced the most expensive part on car.? why ?
replace PCM. ! wow ! what if used PCM (is it used) is bad,?
if so now 2 problems, Compounding every thing,.....$$$$$$$$

last time it ran was 1 week ago , 1 year, what? miles on it?
bad fuel in tank , old?
why not elaborate that key symptom first.?
there is a cluster there.
gauges, warning lights. many, all must glow.
lets do this dance, posted 100 times;. now.
  1. head lights work not dim? key in pocket.
  2. key on, not cranked ! (covered in missing oper. guide)
  3. all warning lights glow, if not battery is weak or fuses blown.
  4. and the CEL lamp there, it must glow or the PCM has no power ,that too, is a blown PCM fuse. fact. (or lamp dead)
  5. lets say the lamp was dead,CEL the scan tools hows status of the lamp and all else, so use a $10 scan too now. does it communicate with the PCM and show all sensors and not DTC errors? scan it now, cant fix cars now , with no scan tool , buy one, and win on old cars. big time with pay back !!! heck all cars. 96+
  6. so the CEL glows now, good, now you crank, now, does the crank shaft turn fast cranking, yes/no. yes !
  7. then check for spark , got spark x 6?
  8. got spark well test fuel works now , even with dry gas tank.
  9. is the ASD relay closing and then dropping,? ( yes, and yes)
  10. then that means the PCM cut fuel , on purpose !!!!
  11. the scan tool tells you why. it did drop for sure. scan it.

1993 to now , MR. ASD 101

http://www.fixkick.com/Jeeps/ASD.html

PCM is the engine EFI brain, it runs all spark and all fuel all the time. it also dumps the ASD to stop engine fires, by law.
confuses many, and all cars have this, one way or the other,
all EFI cars.

Feb 25, 2015 | 1997 Jeep Grand Cherokee

2 Answers

Need help troubleshooting 89 omni?


You need a scanner. Does the PCM see the engine cranking?
Are the injectors firing (evidence PCM see's engine cranking)?
Does the system show it is firing? This is things you need to know to diagnosis a a no start/hard starting engine.
I've seen Dodges not seeing engine crank due to bad crank sensors. Usually jeeps.
Good luck and ask more if needed?

Jan 30, 2015 | 1989 Dodge Omni

1 Answer

Crank shaft sensor, 99' taurus


If the crank sensor is bad you will not get any spark. The PCM does not know the engine is turning with no crank sensor signal so it it does nothing.

What else is it doing?

Feb 24, 2014 | Ford Taurus Cars & Trucks

1 Answer

2000 Grand Caravan cranks but doesn't run. If I bypass the automatic shut-down relay it'll run for about 3 seconds, but starts surging and conks out. Both the cam & crank position sensors test okay....


the pcm energizes that relay. should be a dark blue wire with a yellow stripe going from pcm pin 67 to pin 8 on power dist center. check all fuses then check wire. Is the check engine light on with key on? Possible bad pcm.

Dec 04, 2013 | 2000 Dodge Grand Caravan

1 Answer

2002 Hyundai Sante Fe 2.4L


a crank sensor is a magnetic pulse sensor that tells the pcm(computer) how fast the engine is running. it sends an ac voltage to the pcm and that tells the pcm how fast and at what rpm the engine is running. there are no moving parts to the crank sensor itself. it just sends a pulse but it may be shorted or grounded or open. shorted can be caused be heat or liquid infiltration and will cause the signal to be skewed. grounded or open had to do with the windings in the inside. grounded means it has a wire toughing ground on the engine and open means it has a broken wire either inside or in the harness. i don't know where it is on that vehicle.

May 07, 2009 | 2002 Hyundai Santa Fe

1 Answer

2003 Caravan No Crank, 3.3L


This is a bad PCM. Try to disconnect the security system first and if it still does not start then it is the PCM.

Aug 09, 2008 | 2003 Dodge Caravan

Not finding what you are looking for?
2004 Jeep Liberty Logo

Related Topics:

27 people viewed this question

Ask a Question

Usually answered in minutes!

Top Jeep Experts

yadayada
yadayada

Level 3 Expert

74896 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22095 Answers

Jeff Turcotte
Jeff Turcotte

Level 3 Expert

7688 Answers

Are you a Jeep Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...