Ls1 Swap...OBII Port question
08-13-2013, 08:40 PM
#1
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Ls1 Swap...OBII Port question So I swapped a 99 ls1/auto from a T/A into a 95 Z28.
How exactly does the OBDII port work? My mechanic is trying to plug in a scanner for a CEL and it isn't reading right.
During the swap I have not touched the wiring from the OBDII port so it is the stock 95 Z port as far as I know.
Anyone have the wiring/wiring guide for what needs to go where for a scanner to read properly?
How exactly does the OBDII port work? My mechanic is trying to plug in a scanner for a CEL and it isn't reading right.
During the swap I have not touched the wiring from the OBDII port so it is the stock 95 Z port as far as I know.
Anyone have the wiring/wiring guide for what needs to go where for a scanner to read properly?
08-13-2013, 10:00 PM
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Found this on lt1swap.com:
OBD2 DIAGNOSTIC PORT WIRING
All OBD2 port's for LS1, Vortec Truck are the same.
Pin 2. - Serial Data - FROM the PCM.
Pin 4 & 5 - GROUND - Usually only pin 5 is needed, however some scan tools/code readers will need GROUND on pin 4 as well.
Pin 16 - 12v+ BATTERY - Power from 12v+ Battery source.
OBD2 LT1, 96-97 ONLY will have additional wiring to OBD2 port.
Pin 6 - Diagnostic Request/Field Output Enable
Pin 9 - UART Serial Data
1995 LT1 used an OBD2 port, but were not OBD2 vehicles. These did not have a Serial Data on Pin 2. These used pin 9.
It looks like I should have the purple serial data wire in pin 9, but where do I take that wire in the pcm?
On the 95, It was in C105 Pin E I believe:
E Tan Serial data signal (VIN P and K)
On the 99, It is in C230 K:
K Dark Green 1049 PCM Class 2 Serial Data
PCM BLUE Pin 58: DK GRN 1049 ECM/PCM/VCM Class 2 Serial Data
Right now I have both of those wires in C100 E .
So I should be able to just splice into one of those wires with a new wire coming out from the Serial Data Pin #9 in the OBDII port?
Also, are the grounds just wires needing to go to a body ground?
OBD2 DIAGNOSTIC PORT WIRING
All OBD2 port's for LS1, Vortec Truck are the same.
Pin 2. - Serial Data - FROM the PCM.
Pin 4 & 5 - GROUND - Usually only pin 5 is needed, however some scan tools/code readers will need GROUND on pin 4 as well.
Pin 16 - 12v+ BATTERY - Power from 12v+ Battery source.
OBD2 LT1, 96-97 ONLY will have additional wiring to OBD2 port.
Pin 6 - Diagnostic Request/Field Output Enable
Pin 9 - UART Serial Data
1995 LT1 used an OBD2 port, but were not OBD2 vehicles. These did not have a Serial Data on Pin 2. These used pin 9.
It looks like I should have the purple serial data wire in pin 9, but where do I take that wire in the pcm?
On the 95, It was in C105 Pin E I believe:
E Tan Serial data signal (VIN P and K)
On the 99, It is in C230 K:
K Dark Green 1049 PCM Class 2 Serial Data
PCM BLUE Pin 58: DK GRN 1049 ECM/PCM/VCM Class 2 Serial Data
Right now I have both of those wires in C100 E .
So I should be able to just splice into one of those wires with a new wire coming out from the Serial Data Pin #9 in the OBDII port?
Also, are the grounds just wires needing to go to a body ground?
08-14-2013, 06:21 PM
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Ground is just body ground.
The serial data wire from your PCM needs to go to pin 2.
If your port doesn't have a wire there, go to the local pick-n-pull and grab one from any 2000s GM car.
The serial data wire from your PCM needs to go to pin 2.
If your port doesn't have a wire there, go to the local pick-n-pull and grab one from any 2000s GM car.
