skip shift & reverse lock out not working
04-29-2006, 12:48 PM
#1
Racer
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Location: Massachusetts
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St. Jude Donor '10
skip shift & reverse lock out not working
when I bought a 2 year old 2003 AE with 4200 miles I thought it was great that the skip shift did not work.
The carfax also checked out fine.
Recently I became aware of the reverse lockout. Up until recently I just thought it was poor GM design that a person could go from 4th to reverse.
I found both solinoids and they are plugged in properly (pg 7-8 of the manual). page 7-101 describes the operation of skip shift and reverse lockout. I know that skip shift is sending a signal to the dashboard since the skip shift lamp comes on.
Usually but not always it is hard to go into reverse when I am parking the car, and sometimes when I think it is reverse it pops out.
I would like to have the reverse lockout working.
Should I do a shift linkage adjustment (pg 7-68) to fix the problem of going into reverse? I would think I should have trouble with other gears also, but 1-5 shift fine.
I have checked fuse 19 under the hood and it is fine.
I replaced the transmission fluid when I bought the car.
questions-
1. what would prevent the solenoids from working but allow the skip shift lamp to light?
2. when people disable skip shift where do they disable it from?
3. Is there a connector somewhere that is unplugged that controls skip shift and reverse lockout?
4. I have heard people mention that reverse solenoid internal parts can come loose and fall to the bottom of the transmission. Is this possibly part of my problem?
5. Could the problem be just a "lazy" solenoid and i am able to apply enough pressure to hit reverse from 4th?
6. grounding problem?
7. other suggestions?
The carfax also checked out fine.
Recently I became aware of the reverse lockout. Up until recently I just thought it was poor GM design that a person could go from 4th to reverse.
I found both solinoids and they are plugged in properly (pg 7-8 of the manual). page 7-101 describes the operation of skip shift and reverse lockout. I know that skip shift is sending a signal to the dashboard since the skip shift lamp comes on.
Usually but not always it is hard to go into reverse when I am parking the car, and sometimes when I think it is reverse it pops out.
I would like to have the reverse lockout working.
Should I do a shift linkage adjustment (pg 7-68) to fix the problem of going into reverse? I would think I should have trouble with other gears also, but 1-5 shift fine.
I have checked fuse 19 under the hood and it is fine.
I replaced the transmission fluid when I bought the car.
questions-
1. what would prevent the solenoids from working but allow the skip shift lamp to light?
2. when people disable skip shift where do they disable it from?
3. Is there a connector somewhere that is unplugged that controls skip shift and reverse lockout?
4. I have heard people mention that reverse solenoid internal parts can come loose and fall to the bottom of the transmission. Is this possibly part of my problem?
5. Could the problem be just a "lazy" solenoid and i am able to apply enough pressure to hit reverse from 4th?
6. grounding problem?
7. other suggestions?
Last edited by sdef; 04-29-2006 at 01:35 PM.
04-29-2006, 01:31 PM
#2
CAGs and lockout may have been turned off with a PCM tune.
If you tested wires from the PCM to the connectors by the transmisson would say somehow the wires did not get cut in the drivetube tunnel during past work requiring drivetube to come out which leads to a bad reverse lockout but the PCM should then be reporting error codes for it.
If you tested wires from the PCM to the connectors by the transmisson would say somehow the wires did not get cut in the drivetube tunnel during past work requiring drivetube to come out which leads to a bad reverse lockout but the PCM should then be reporting error codes for it.
04-29-2006, 06:58 PM
#3
Le Mans Master
I am not so sure that the skip shift light working means that the solenoid is sending a signal. It probably just means the computer is seeing the correct resistance, meaning that the solenoid is plugged in.
The skip shift by-pass kits just have a plug that simulates the solenoid resistance so there are no error codes, but the light on the dash still comes on. When the kit is installed, the skip shift solenoid is unplugged (and stays disconnected) and the simulator resistance is plugged into the wiring harness in place of the solenoid.
The reverse lockout is separate from the skip shift solenoid as you already pointed out.
The skip shift by-pass kits just have a plug that simulates the solenoid resistance so there are no error codes, but the light on the dash still comes on. When the kit is installed, the skip shift solenoid is unplugged (and stays disconnected) and the simulator resistance is plugged into the wiring harness in place of the solenoid.
The reverse lockout is separate from the skip shift solenoid as you already pointed out.
Last edited by TEXHAWK0; 04-29-2006 at 07:01 PM.
04-29-2006, 07:40 PM
#4
Race Director
You could crawl up there and disconnect the two plugs for the solenoid and CAGS and see if you get an error code. If no errors, Someone probably tuned them out or you have a wiring issue.
04-30-2006, 10:59 AM
#5
Racer
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St. Jude Donor '10
Thank you for your responses.
Boosted z06,
If CAGS can be turned off then I wonder why people buy the CAGS bypass.
Shouldn’t I see an error code on the dash if the PCM is seeing a bad solenoid?
Have you been inside the drivetube tunnel? I would assume there are more wires in there than the skip shift and reverse solenoid?
Texhawko,
Correct, rereading 7-101 the PCM controls the solenoid and light, so one could work and not the other.
Ajg1915,
The reverse solenoid is next to impossible to get to. I would hate to get it off and not be able to get it back on.
Disconnecting the skip shift is easier. I assume if I disconnect it I will receive an error message on the dash?
________________________________________ __
________________________________________ ___
What is a PCM (powetrain control module) tune?
When people have the car “tuned” what is the nondealership tech actually trying to do? The tune is strictly to increase performance?
I can see why during a tune the skip shift is turned off, but why would someone want to turn off reverse lockout?
sdef
If CAGS can be turned off then I wonder why people buy the CAGS bypass.
Shouldn’t I see an error code on the dash if the PCM is seeing a bad solenoid?
Have you been inside the drivetube tunnel? I would assume there are more wires in there than the skip shift and reverse solenoid?
Texhawko,
Correct, rereading 7-101 the PCM controls the solenoid and light, so one could work and not the other.
Ajg1915,
The reverse solenoid is next to impossible to get to. I would hate to get it off and not be able to get it back on.
Disconnecting the skip shift is easier. I assume if I disconnect it I will receive an error message on the dash?
________________________________________ __
________________________________________ ___
What is a PCM (powetrain control module) tune?
When people have the car “tuned” what is the nondealership tech actually trying to do? The tune is strictly to increase performance?
I can see why during a tune the skip shift is turned off, but why would someone want to turn off reverse lockout?
sdef
04-30-2006, 01:08 PM
#6
There can be multi reasons something is turned off in the PCM via a tune, from past owner wanting to sell the car and hide faults by turning not only the function but also the error codes off so others are not aware of problems when they buy the car used.
Some error codes
P0801 Reverse Inhibit Control Circuit Malfunction
P0803 1-4 Upshift (Skip Shift) Solenoid Control Circuit Malfunction
P0804 1-4 Upshift (Skip Shift) Lamp Control Circuit Malfunction
If codes were turned off most times someone could not find the problem or did not want to fix them so they turn off the error codes so they would not show up on the DIC or via a PCM scanner.
If having PCM tuned its easier to turn off CAGs so dealer would not see it it was disconnected at the transmission
Being the wiring sits above the drivetube sometimes when the tube is taken out and care is not used the end of tube hits wires and damages some of them.
It could even be that someone flashed the PCM with the wrong software or even acid damage from battery has effected wires for the transmission.
You need to use a PCM scanner that has bi-directional mode which would allow sending commands to lockout or CAGS and see how they respond. any error codes produced and if you think the hardware in trannie is good then have someone download your PCM and see what is configured on or off and if the error codes were turned off
Still as to reverse lockout is a simple test, when in reverse or not then measure its wires and see if there is a change between the two modes
Some error codes
P0801 Reverse Inhibit Control Circuit Malfunction
P0803 1-4 Upshift (Skip Shift) Solenoid Control Circuit Malfunction
P0804 1-4 Upshift (Skip Shift) Lamp Control Circuit Malfunction
If codes were turned off most times someone could not find the problem or did not want to fix them so they turn off the error codes so they would not show up on the DIC or via a PCM scanner.
If having PCM tuned its easier to turn off CAGs so dealer would not see it it was disconnected at the transmission
Being the wiring sits above the drivetube sometimes when the tube is taken out and care is not used the end of tube hits wires and damages some of them.
It could even be that someone flashed the PCM with the wrong software or even acid damage from battery has effected wires for the transmission.
You need to use a PCM scanner that has bi-directional mode which would allow sending commands to lockout or CAGS and see how they respond. any error codes produced and if you think the hardware in trannie is good then have someone download your PCM and see what is configured on or off and if the error codes were turned off
Still as to reverse lockout is a simple test, when in reverse or not then measure its wires and see if there is a change between the two modes
Originally Posted by sdef
Boosted z06,
If CAGS can be turned off then I wonder why people buy the CAGS bypass.
Shouldn’t I see an error code on the dash if the PCM is seeing a bad solenoid?
Have you been inside the drivetube tunnel? I would assume there are more wires in there than the skip shift and reverse solenoid?
Texhawko,
Correct, rereading 7-101 the PCM controls the solenoid and light, so one could work and not the other.
Ajg1915,
The reverse solenoid is next to impossible to get to. I would hate to get it off and not be able to get it back on.
Disconnecting the skip shift is easier. I assume if I disconnect it I will receive an error message on the dash?
________________________________________ __
________________________________________ ___
What is a PCM (powetrain control module) tune?
When people have the car “tuned” what is the nondealership tech actually trying to do? The tune is strictly to increase performance?
I can see why during a tune the skip shift is turned off, but why would someone want to turn off reverse lockout?
sdef
If CAGS can be turned off then I wonder why people buy the CAGS bypass.
Shouldn’t I see an error code on the dash if the PCM is seeing a bad solenoid?
Have you been inside the drivetube tunnel? I would assume there are more wires in there than the skip shift and reverse solenoid?
Texhawko,
Correct, rereading 7-101 the PCM controls the solenoid and light, so one could work and not the other.
Ajg1915,
The reverse solenoid is next to impossible to get to. I would hate to get it off and not be able to get it back on.
Disconnecting the skip shift is easier. I assume if I disconnect it I will receive an error message on the dash?
________________________________________ __
________________________________________ ___
What is a PCM (powetrain control module) tune?
When people have the car “tuned” what is the nondealership tech actually trying to do? The tune is strictly to increase performance?
I can see why during a tune the skip shift is turned off, but why would someone want to turn off reverse lockout?
sdef
05-01-2006, 12:10 AM
#7
Race Director
I'm not sure where you live since you did't post that information in your profile.
From the pictures of your vette, it does not seem that you are heavy modder and own your own handheld programmer.
You might post where you live and ask some of the forum members for shop recomendations on where you take your vette to get fixed.
A lot of people tune out the CAGS so they are not forced to shift from 1st to 4th.
As far as the reverse lockout you may just have a bad solenoid or a broken wire. Electrical problems are a time consuming endevor to work out. Its a matter of elimination.
From the pictures of your vette, it does not seem that you are heavy modder and own your own handheld programmer.
You might post where you live and ask some of the forum members for shop recomendations on where you take your vette to get fixed.
A lot of people tune out the CAGS so they are not forced to shift from 1st to 4th.
As far as the reverse lockout you may just have a bad solenoid or a broken wire. Electrical problems are a time consuming endevor to work out. Its a matter of elimination.
