Remote Start Problem - JeepForum.com
 3Likes
Reply
 
LinkBack Thread Tools
post #1 of 18 Old 01-24-2020, 12:30 PM Thread Starter
jpbmass
Registered User
 
Join Date: Dec 2019
Posts: 8
Remote Start Problem

My 2012 Grand Cherokee Laredo remote-start quite working; I get the "hood ajar" error message on the dash. After reading earlier posts, I disconnected the hood latch electrical cable and shorted out the inboard connector -- no joy! Anybody have any suggestions???

jpbmass is offline  
Sponsored Links
Advertisement
 
post #2 of 18 Old 01-24-2020, 03:07 PM
2014RedHemiGC
Registered User
 
2014RedHemiGC's Avatar
2014 WK 
 
Join Date: Jul 2013
Location: Mount Airy, NC
Posts: 524
Thereís a long list of conditions listed in the manual that can prevent remote start from working. The most common is low fuel level in case you hadnít checked. Also, certain stored codes will prevent it as well.

2014 Deep Cherry Red GC 4X4 V8 QDII
2012 Crystal Red Cadillac CTS-V Coupe
2011 Crystal Red Chevy Corvette Z06/Z07
2014RedHemiGC is offline  
post #3 of 18 Old 01-24-2020, 06:05 PM
ColdCase
My Reality Check Bounced
 
ColdCase's Avatar
2011 WK 
 
Join Date: Sep 2009
Location: New England
Posts: 14,948
Are you still getting the hood ajar message? If so I'd double check your connections and check the wire harness for damage. Off hand I forget if there are one or two pins in the latch connector. While on, measure the voltage in the harness connector between a pin and a good chassis ground. One should be about 5Volts, the other should be pretty close to ground potential.

I was born to party, but I am forced to work
Current: 2011 Grand Cherokee Overland V8, 2009 Liberty Rocky Mt V6
Previous: 2000 Grand Cherokee Laredo I6, 1979 CJ7 I6 Quadratrac
ColdCase is offline  
 
post #4 of 18 Old 01-25-2020, 03:28 AM Thread Starter
jpbmass
Registered User
 
Join Date: Dec 2019
Posts: 8
Lots of fuel, No "check engine" codes, yes- I'm still getting the hood ajar message.This is a two pin connector with no apparent damage to wire harness. Will check the voltages and repost.
jpbmass is offline  
post #5 of 18 Old 01-25-2020, 06:29 AM
wickedace
Registered User
2014 WK 
 
Join Date: Sep 2015
Location: Worchester
Posts: 14
Quote:
Originally Posted by jpbmass View Post
Lots of fuel, No "check engine" codes, yes- I'm still getting the hood ajar message.This is a two pin connector with no apparent damage to wire harness. Will check the voltages and repost.
Two pins at the connector would suggest a switch is used to satisfy the condition. Possibly a plunger type switch. After you confirm voltage at the connector and with the connector off the switch try it to see if it is in fact changing state by manipulating the switch with your VOM set to ohms.
wickedace is offline  
post #6 of 18 Old 01-25-2020, 07:55 AM
ColdCase
My Reality Check Bounced
 
ColdCase's Avatar
2011 WK 
 
Join Date: Sep 2009
Location: New England
Posts: 14,948
The service manual says the hood ajar switch is a single pole, spring-loaded plunger actuated switch that is integral to the hood latch mechanism. When the hood is closed and properly latched, the latch mounted hood ajar switch is an open circuit.

So it looks like you should not short the pins, just disconnect the connector. Dunno but you may want to try that, if you haven't already.

I was born to party, but I am forced to work
Current: 2011 Grand Cherokee Overland V8, 2009 Liberty Rocky Mt V6
Previous: 2000 Grand Cherokee Laredo I6, 1979 CJ7 I6 Quadratrac
ColdCase is offline  
post #7 of 18 Old 01-25-2020, 10:25 AM Thread Starter
jpbmass
Registered User
 
Join Date: Dec 2019
Posts: 8
OK -- I tried to start with connector disconnected; still no start, hood ajar. Measured the voltage at the connector - one socket is ground, the other is about 1.7 volts?? Measured resistance: when hood latch is open, switch is closed (zero resistance), when hood latch is closed, switch is open (high resistance). I guess the latch switch is working OK, maybe the low connector voltage is the problem? What could cause that??
jpbmass is offline  
post #8 of 18 Old 01-25-2020, 10:43 AM
ColdCase
My Reality Check Bounced
 
ColdCase's Avatar
2011 WK 
 
Join Date: Sep 2009
Location: New England
Posts: 14,948
I don’t have a schematic or a wiring diagram that includes the latch handy. But I could guess.

Typically with these types of circuits there is a “driver” in a module that provides a low current 5v reference signal and senses current. (None with switch open, some when switch closed). Perhaps the PCM or TIPM, whichever is monitoring the latch, has an issue with the driver, or your meter is drawing enough current to bring down the reference voltage. Unlikely, however. If it was 5v or 0 it would be easier to draw a conclusion, dunno about 1.7. That could be normal, but I’d expect 5 or 12 volts.

I didn’t see a DTC fault for the latch listed, but there may be one stored. These would not trip a check engine.

I don’t recall reading about a similar issue, but there have been some latches go bad.

Perhaps someone will drop in here with a more relevant answer or a wire diagram and circuit description.


Does it measure 1.7 across the pins?

The open/closed circuit switch state is opposite from my newer model tech data, but since you get the ajar with both the harness pins shorted and open, thats probably irrelevant.

I was born to party, but I am forced to work
Current: 2011 Grand Cherokee Overland V8, 2009 Liberty Rocky Mt V6
Previous: 2000 Grand Cherokee Laredo I6, 1979 CJ7 I6 Quadratrac
ColdCase is offline  
post #9 of 18 Old 01-25-2020, 10:54 AM
wickedace
Registered User
2014 WK 
 
Join Date: Sep 2015
Location: Worchester
Posts: 14
Quote:
Originally Posted by jpbmass View Post
OK -- I tried to start with connector disconnected; still no start, hood ajar. Measured the voltage at the connector - one socket is ground, the other is about 1.7 volts?? Measured resistance: when hood latch is open, switch is closed (zero resistance), when hood latch is closed, switch is open (high resistance). I guess the latch switch is working OK, maybe the low connector voltage is the problem? What could cause that??
When you measured voltage to the connector did you measure pin to pin or pin to chassis ground? A higher potential when measuring pin to ground would indicate a possible short either wire to wire or power wire to ground. Tis the season for little critters to visit!
wickedace is offline  
post #10 of 18 Old 01-25-2020, 11:26 AM
ColdCase
My Reality Check Bounced
 
ColdCase's Avatar
2011 WK 
 
Join Date: Sep 2009
Location: New England
Posts: 14,948
Oh, on second thought, there is fault detection circuit in most of the the modules, you may have to use a 1k ohm resister instead of a wire between the pins.

If that works, you'll have to replace the latch for safety. The switch is not separately reparable.

Sorry the mind is a bit slow today....

I was born to party, but I am forced to work
Current: 2011 Grand Cherokee Overland V8, 2009 Liberty Rocky Mt V6
Previous: 2000 Grand Cherokee Laredo I6, 1979 CJ7 I6 Quadratrac
ColdCase is offline  
post #11 of 18 Old 01-25-2020, 11:35 AM Thread Starter
jpbmass
Registered User
 
Join Date: Dec 2019
Posts: 8
Attached scan tool, no DTC codes stored. Yes, 1.7 vdc across the pins as well as pin to ground.
jpbmass is offline  
post #12 of 18 Old 01-25-2020, 11:52 AM Thread Starter
jpbmass
Registered User
 
Join Date: Dec 2019
Posts: 8
I measured resistance with D VOM on 200 ohm scale -- measured zero with hood latch open. I don't have a 1 ohm resistor to try, but am guessing adding that instead of wire jumper will make no difference.
jpbmass is offline  
post #13 of 18 Old 01-25-2020, 12:01 PM
ColdCase
My Reality Check Bounced
 
ColdCase's Avatar
2011 WK 
 
Join Date: Sep 2009
Location: New England
Posts: 14,948
Not a 1 ohm, a 1000 ohm (1K ohm). Just saying that others have had success with a resistor where a wire failed them. Something about the way shorts are detected and current limiting.

I assume you know you need a scan tool that can read TIPM and body module codes to be sure, not an everyday scanner.

I was born to party, but I am forced to work
Current: 2011 Grand Cherokee Overland V8, 2009 Liberty Rocky Mt V6
Previous: 2000 Grand Cherokee Laredo I6, 1979 CJ7 I6 Quadratrac
ColdCase is offline  
post #14 of 18 Old 01-25-2020, 12:36 PM Thread Starter
jpbmass
Registered User
 
Join Date: Dec 2019
Posts: 8
My scanner is just an everyday scanner and my long-dormant box of resistors is hiding somewhere. Guess I'll have to break down and take it to the dealer :-( Thanks so much for all your help -- will let you know what they find.
jpbmass is offline  
post #15 of 18 Old 01-26-2020, 12:23 PM
MJS
Registered User
2014 WK 
 
Join Date: Feb 2009
Location: Ohio
Posts: 91
I had the same issue at one point. Sprayed the connector and latch area with some PB Blaster or something (can't remember). Wiped it all down. Been fine ever since.
MJS is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.



Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome