V
vegasviper
Guest
On my 97 GTS
HP
Enthusiast
The MAP sensor is supplied with 5v from the PCM - it's located on top of
the intake manifold - black plastic piece near the firewall.
It has a connector that has 3 contacts - input of 5v from PCM - ground from PCM
and a center contact that is the ouput signal which is a function of the
vacuum from the intake,
with the ignition off, unplug the connector and inspect it - maybe apply a
little ignition grease - and reconnect it. Usually this will correct it.
If not, you may have to pull the PCM plug and MAP plug and check for a short in
one of the 3 wires.
the intake manifold - black plastic piece near the firewall.
It has a connector that has 3 contacts - input of 5v from PCM - ground from PCM
and a center contact that is the ouput signal which is a function of the
vacuum from the intake,
with the ignition off, unplug the connector and inspect it - maybe apply a
little ignition grease - and reconnect it. Usually this will correct it.
If not, you may have to pull the PCM plug and MAP plug and check for a short in
one of the 3 wires.
OP
OP
vegasviper
Guest
HP, i replaced the MAP and disconected PCM and no change. How do you test for short??
OP
OP
vegasviper
Guest
Also, i erased the code but it keeps coming back up. When you clear the code, is it still stored in pcm or gone for good
HP
Enthusiast
To test for short - you need the locate the 3 wires on the PCM plug and
do a continuity check (Ohm reading) between each.
do a continuity check (Ohm reading) between each.
HP
Enthusiast
Shoot me an e-mail and I'll walk you through it.
OP
OP
vegasviper
Guest
Ok, i have an ohm meter, do i just instert into plugs and read? what should it read
HP
Enthusiast
take an ohm tool insert one probe in one contact and the other in one of the
other 2 contacts - basically your ohm reading shouldn't change - if it does
there is a short between the wires. specifically if the you get less than 5(Ohms) You can also test to see if any of the wires is shorted to ground,
use one probe on the wire and the other to ground - if you get less than 5(OHMS)
there is a short.
This is done with both connections unplugged and the ignition off.
other 2 contacts - basically your ohm reading shouldn't change - if it does
there is a short between the wires. specifically if the you get less than 5(Ohms) You can also test to see if any of the wires is shorted to ground,
use one probe on the wire and the other to ground - if you get less than 5(OHMS)
there is a short.
This is done with both connections unplugged and the ignition off.
HP
Enthusiast
Before you test for a short, make sure that you have tested the MAP connector
to see what the voltage input actually is - do this with the car off
and ignition on. The input voltage wire is orange. you should get between 4.5
and 5 volts. unplug the MAP connector and test the plug with the incoming
wires attached. Make sure the PCM plug is plugged in.
If it tests above 4.5v - then plug it in and go drive the car -
I've thrown a code like that and after checking everything - it just
straightened out by itself.
to see what the voltage input actually is - do this with the car off
and ignition on. The input voltage wire is orange. you should get between 4.5
and 5 volts. unplug the MAP connector and test the plug with the incoming
wires attached. Make sure the PCM plug is plugged in.
If it tests above 4.5v - then plug it in and go drive the car -
I've thrown a code like that and after checking everything - it just
straightened out by itself.
HP
Enthusiast
If you can't find a short - then the PCM may have to be replaced
jimandela
Enthusiast
vegasviper,
was it the dreaded code 1296?
that ticked me off for over a week and kept coming back now and again.
it turned out that i need my Roe VEC1 wires sodered, all of them ..
and now no more 1296 "map code"
was it the dreaded code 1296?
that ticked me off for over a week and kept coming back now and again.
it turned out that i need my Roe VEC1 wires sodered, all of them ..
and now no more 1296 "map code"
OP
OP
vegasviper
Guest
HP, when i clear the code with obd tool does it sill remain in pcm but does not show up in check engine light
OP
OP
vegasviper
Guest
cant remember if it was code 1296, i wonder if my obd tool stores the code that showed up
HP
Enthusiast
I 'think' when you erase a code - it's gone- period
But I'm reaching a little - on that - you may want to ask a higher authority
jimandela
Enthusiast
vegas,
first email reply
Clear the code, check your electrical connections and reset the VEC1.
The VEC1 is tied into the MAP sensor circuit.
If that code sets, the PCM will go into limp home mode as that's a
primary input for determining fuel and spark settings.
then when it keep popping the code 2nd reply
Make sure the power wire is positive in key on and start (while the
starter is turning). If not, you may be on the wrong power wire.
Otherwise, it's the ground, VEC1 box or possibly a bad connection
somewhere else within that circuit.
i used the cheap $40 roe code reader/clearer
had all wires sodered and now i am set.
good luck
JIM
first email reply
Clear the code, check your electrical connections and reset the VEC1.
The VEC1 is tied into the MAP sensor circuit.
If that code sets, the PCM will go into limp home mode as that's a
primary input for determining fuel and spark settings.
then when it keep popping the code 2nd reply
Make sure the power wire is positive in key on and start (while the
starter is turning). If not, you may be on the wrong power wire.
Otherwise, it's the ground, VEC1 box or possibly a bad connection
somewhere else within that circuit.
i used the cheap $40 roe code reader/clearer
had all wires sodered and now i am set.
good luck
JIM
OP
OP
vegasviper
Guest
So Jim, did your engine break up at higher RPM 5000-6000RPM as a result of bad conection
Mike Adams
Enthusiast
Call me VEGASVIPER. I can tell you exactly what is wrong and how to check. If you have an OHM meter or a 'HIGH IMPEDENCE TEST LIGHT' it will be easy for you to check
519 763 8473
519 763 8473
jimandela
Enthusiast
vegas,
no, the check light just came on code 1296, it ran poorly .. talked with Sean figured it was
the loose wiring and sodered it.. now life is good...and i sent you a email as well....
good luck
best wishes
Jim
no, the check light just came on code 1296, it ran poorly .. talked with Sean figured it was
the loose wiring and sodered it.. now life is good...and i sent you a email as well....
good luck
best wishes
Jim
Mike Adams
Enthusiast
ps problem is not a map sensor or your VEC2
HP
Enthusiast
Since I don't have a VEC, or a wiring diagram related to a VEC,
please post your final conclusions.
Any time you intercept or manipulate sensor output - you add another
variable to the mix.
please post your final conclusions.
Any time you intercept or manipulate sensor output - you add another
variable to the mix.
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