I get an intermittent "Coolant Sensor Bad" message on the VIC...the coolant level sensor was changed out as was its connector...how do I make this annoying message stop? Interestingly, it happens less in cold weather... Checked out all other coolant sensors via the OBDII port and all was showing proper function...
The coolant sensor and the coolant level sensor are two different sensors. Your message center is showing (coolant sensor bad),not level sensor bad.
The level sensor only monitors the amount of coolant in the container
The coolant sensor senses the degrees of the coolant, which turns on the electric cooling fans. Change the coolant sensor, and the problem should go away.
the error with bad in it , is always the bottle. per fsm pages below, image 1
bad means the bottle sensor reads 12v
which means this path is open.
the line has 2 legit voltages
0v (empty bottle) (grounded)
and way less that 12v, my guess 6v.
12v means open line. can be the sensor switch
the 2 wires
are a bad vic.
a bad vic the voltage at the sensor would be 0v all the time and 12v at the vics processor.
can be just the pin solder joint cracked,
we see them all the time.
vic 12v, resistor >>pin vic >>> switch >>>gnd
the vic has pull up resistor. inside.
this resistor i guess is same as in the switch.
so if the line open the vic sees 12v a "bad".
if the line switch (normal)is at 3k, we get 6v.?
if the line switch grounds (0v) the vic sees
0v. and shows empty bottle.
im that guy that fixes the brain side..
i can draw the circuits, ask.
not true, the proof is in the FSM
the VIC message has only one meaning.
BAD means:
THE BOTTLE SWITCH line is cut. in some way
that includes the VIC display pin for same
cracked,
it's a computer input and is pulled up internally to go to high voltage (5v or 12v).
this high voltage is FAIL detection,
means no current is flowing and a message
is displayed as bad.
if you ground this VIC pin, and it shows bad
that proves the VIC is bad. fixed many. like it.
lets be more clear.
the line open can be ,
the total , circuit. end to end
starting at an open ground on switch side
all the way to the HEAD and then inside the head, it too can have cracked solder pin that goes open so often due to vibration.
all bad means, to the brain is
the line is open and draws zero current.
dead 100% open. or close.
because im the chap that fixes the brain
i know all these facts.
this version is a 3 level analog input to the brain.
I cut teeth on PLC, and before that we be built them (from scratch) before the world knew what PLC ment. and later the laggard car companies.
(industry)
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Posted by on Nov 16, 2009 !!!!!!!! revived by piggy-backer.
the sensor is in the bottom of the side overfill tank, and is a fload switch (and hidden resistor),
The exact message " coolant bottle low/bad"
in your case it shows the BAD word, (matters)
this means the bottle switch is open
and not 3000 ohms, (normal) nor zero ohms as it must be.
the Cluster brain has 3 level logic.
0 ohms full.
3000 empty
open line BAD , means cut line. open on ground end cut.
or the wire to the Cluster at the pin on the cluster is cracked,(solder crack easy fix )
the cluster forces current down this wire.
if no current flows at all , the line is bad.(open)
dead open, why/where its open the cluster dont know
only that it is. (it actually measures volts there)
the acid test, is ground the cluster pin direct to ground, if BAD word fails to show, the cluster is ok.
if bad Shows, now, the cluster is bad.
easy.
the word "BAD" is the key to why,
it has only 1 meaning on this car.
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I'm in the UK. I have a 1998 Grand Cherokee. For 2 years I have been getting a 'Coolant level sensor bad' message on the message centre. Two years ago I changed the coolant level sensor which made no difference...
... then I found out that it was a common Jeep fault - an untrue error message. Some things are easily ignored..
2009 posts. ok....
FSM page, its free to read.
page 8w-29 and the one page only that shows what the software means by BAD, cluster brain. Bad = open line fail,hard failure.
so true humans can check levels now for 100 years. zero computers needed to do that..
if i had a nickle for every head jerked
re-soldered and fixed, id be retired early, H3LL , i am. vibration is the killler. or...
Some cars the head PCB soldering job looks like done with no flux. and cold solder joints in the factory, seen lots of Dodges like that. Wave soldering by mad men.
have endless stories on this...topic....
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