Neutral safety/gear indicator - Chevy Impala Forums
Automotive Discussion General automotive related discussion only.

User Tag List

 3Likes
  • 2 Post By plano-doug
  • 1 Post By Jaestes
 
LinkBack Thread Tools Display Modes
post #1 of (permalink) Old 03-18-2019 Thread Starter
Junior Member
 
Jaestes's Avatar
 
Join Date: Feb 2019
Posts: 7
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Thanks: 0
Thanked 3 Times in 2 Posts
Neutral safety/gear indicator

Just finished reaplacing the engine. I have another thread about that. I've got an issue now, the gear indicator on the dash does not show any gear selected. Which means it wont let it start. I've tried reseating the connectors on the trans, computer, and fuse panel. Any other ideas I can try when I get home?
Jaestes is offline  
Sponsored Links
Advertisement
 
post #2 of (permalink) Old 03-18-2019
Senior Member
 
1999 White C5 Coupe's Avatar
 
Join Date: Jul 2014
Posts: 1,336
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 198 Post(s)
Thanks: 107
Thanked 227 Times in 202 Posts
Quote:
Originally Posted by Jaestes View Post
Just finished reaplacing the engine. I have another thread about that. I've got an issue now, the gear indicator on the dash does not show any gear selected. Which means it wont let it start. I've tried reseating the connectors on the trans, computer, and fuse panel. Any other ideas I can try when I get home?


Year, make, model, trim line would be helpful.
1999 White C5 Coupe is offline  
post #3 of (permalink) Old 03-18-2019 Thread Starter
Junior Member
 
Jaestes's Avatar
 
Join Date: Feb 2019
Posts: 7
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Thanks: 0
Thanked 3 Times in 2 Posts
Sorry I forgot about that. 2012 impala 3.6L base model
Jaestes is offline  
Sponsored Links
Advertisement
 
post #4 of (permalink) Old 03-23-2019 Thread Starter
Junior Member
 
Jaestes's Avatar
 
Join Date: Feb 2019
Posts: 7
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Thanks: 0
Thanked 3 Times in 2 Posts
Any body have any ideas what to look into? I've found the trans range sensor is internal. I did not remove the trans so I'm guessing theres a wiring issue somewhere. Does anyone know where I can find a wiring diagram or any other potentially helpful?
Jaestes is offline  
post #5 of (permalink) Old 03-23-2019
Senior Member
 
plano-doug's Avatar
 
Join Date: Aug 2009
Location: Plano, Texas
Posts: 2,435
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 353 Post(s)
Thanks: 130
Thanked 357 Times in 333 Posts
Quote:
Originally Posted by Jaestes View Post
Any body have any ideas what to look into? I've found the trans range sensor is internal. I did not remove the trans so I'm guessing theres a wiring issue somewhere. Does anyone know where I can find a wiring diagram or any other potentially helpful?
I've attached a drawing I have for the 2008, but I think it should be the same for 2012.

Four wires which indicate the gear shift position go from the transaxle to the transmission control module (TCM). The colors are TN/WH, YE, GY, and WH.

From the TCM, a serial link goes to the instrument cluster. The PRND321 display should reflect what the TCM sees on the four wires above.

A separate, 5th wire goes from the transaxle to the engine control module (ECM). This wire is OG/BK. This signal provides the neutral safety function.

My take is that this is the only signal from the transmission that affects cranking. While the PRND321 display may be blank, all lit up, or on R (for example), the engine should crank if pin W on X100 (at transaxle) is at ~0 volts.

In summary, my take is that the gear selector display issue is separate from the no-crank issue.

Lastly, the other pic attached shows what the four wires from the transmission indicate for the selected gear. The column headings A, B, C and P correspond to pins 29, 46, 23 and 39 respectively at the TCM.

It may be easier to probe these signals at the transaxle connector, X100. There, pins F, G, H and J correspond to A, B, C, and P.

For resolving the no-crank condition, I would start at by probing pin W at the transaxle. It should be low for Park and Neutral, and high for all other positions.

For the PRND321 display issue, probe F, G, H and J, and see if they match the table for all shifter positions.

For the first three rows in the table: For Park, FGHJ should be 0110. If you get 0010, the shifter is between Park and Reverse (if I am interpreting it correctly). For Reverse, FGHJ should be 0011.

HTH.

Doug

.
Attached Thumbnails
Click image for larger version

Name:	2008_impala_IMS_PRNDL.png
Views:	17
Size:	19.2 KB
ID:	145173  
Attached Images
 
sheila and Joes74challenger like this.

_

If your socket set is all the same brand, you might be a city slicker.

.
plano-doug is offline  
post #6 of (permalink) Old 04-05-2019 Thread Starter
Junior Member
 
Jaestes's Avatar
 
Join Date: Feb 2019
Posts: 7
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Thanks: 0
Thanked 3 Times in 2 Posts
Quote:
Originally Posted by plano-doug View Post
Quote:
Originally Posted by Jaestes View Post
Any body have any ideas what to look into? I've found the trans range sensor is internal. I did not remove the trans so I'm guessing theres a wiring issue somewhere. Does anyone know where I can find a wiring diagram or any other potentially helpful?
I've attached a drawing I have for the 2008, but I think it should be the same for 2012.

Four wires which indicate the gear shift position go from the transaxle to the transmission control module (TCM). The colors are TN/WH, YE, GY, and WH.

From the TCM, a serial link goes to the instrument cluster. The PRND321 display should reflect what the TCM sees on the four wires above.

A separate, 5th wire goes from the transaxle to the engine control module (ECM). This wire is OG/BK. This signal provides the neutral safety function.

My take is that this is the only signal from the transmission that affects cranking. While the PRND321 display may be blank, all lit up, or on R (for example), the engine should crank if pin W on X100 (at transaxle) is at ~0 volts.

In summary, my take is that the gear selector display issue is separate from the no-crank issue.

Lastly, the other pic attached shows what the four wires from the transmission indicate for the selected gear. The column headings A, B, C and P correspond to pins 29, 46, 23 and 39 respectively at the TCM.

It may be easier to probe these signals at the transaxle connector, X100. There, pins F, G, H and J correspond to A, B, C, and P.

For resolving the no-crank condition, I would start at by probing pin W at the transaxle. It should be low for Park and Neutral, and high for all other positions.

For the PRND321 display issue, probe F, G, H and J, and see if they match the table for all shifter positions.

For the first three rows in the table: For Park, FGHJ should be 0110. If you get 0010, the shifter is between Park and Reverse (if I am interpreting it correctly). For Reverse, FGHJ should be 0011.

HTH.

Doug

.
Awesome. You were right. The no crank issue is unrelated. I checked those pins and everything was fine according to the meter
started stripping back the harness and found nothing obvious. Hooked a few things back up, and the gear indicator was functional again. Still no crank. Heres where it gets strange. I pulled the starter really from the fuse box and jumped it to get it to crank. It cranked but my scanner saw no rpm, fuel rail pressure and a few other sensors. The 02 sensors are warm and when you try to start with key, the wipers jump a little. I think I need to pull this harness back out and check everything.
plano-doug likes this.
Jaestes is offline  
Sponsored Links
Advertisement
 
Reply

Related Threads
Thread Thread Starter Forum Replies Last Post
2005 Impala 3.4 starts in neutral, stalls Sunbkd Mechanical and Electrical Problems 2 11-16-2018 07:48 AM
50x White Ba9s LED Light Bulb Instrument Speedometer Gauge Cluster Indicator 12V RSS Bot Impala Diecast Toys Cars on eBay 0 08-29-2017 01:20 AM
10x White 5mm Mini LED Bulbs Instrument Cluster Panel Dash Indicator Lights 12v RSS Bot Impala Diecast Toys Cars on eBay 0 08-27-2017 04:10 PM
10x White 5mm Mini LED Bulbs Instrument Cluster Panel Dash Indicator Lights 12v RSS Bot Impala Diecast Toys Cars on eBay 0 08-22-2017 04:10 PM
(5) Yellow Bus Boat Trailer Truck Indicator Light Side Marker 6Led Waterproof RSS Bot Impala Diecast Toys Cars on eBay 0 07-27-2017 02:50 PM


Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Chevy Impala Forums 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 email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



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 On
Pingbacks are On
Refbacks are On

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