Trunknuts

I used a reworked harness for my LM7 (5.3L Tahoe engine) which did not come with a OBD2 diagnostic plug (under-dash plug). I purchased a plug with about 10" of wiring w/ it. Can anyone tell me how to wire it in. I looked in the manual but the schematic shows a "splice connector" between it and the PCM. Can the plug wires go straight to the PCM? And if so, what is the pin out? Thanks in advance for any help.

cherryelky305

iTrader: (2)

my experience is with a camaro harness. however I believe that the general rule is that OBDII ports have 4 wires. two grounds, a constant 12V, and the data line. Wish i could help more, but i dont have my diagrams with me at the moment.

jay_lt4

iTrader: (4)

pin 2 class 2 serial data
pin 4,5 ground
pin 16 12v+

samdogmx

iTrader: (14)

here you go

wajouba

iTrader: (1)

Ok, I have a 240sx with an LS1 swap, and my car is very unstable... I really need to know what codes its firing up at me, but my OBD2 Connecter is not connected... my question is, where is the purple data line located?. do we take it from the original LS1 car dash harness? or is it in the ECU harness?

Thanks

G-Body

iTrader: (4)

The purple serial data wire comes from the LS1 PCM. If you look at the diagrams in the FAQ sticky you should be able to determine which pin it goes to. If not, you need to tell us what year PCM and wiring harness you are using so that we can tell you where to look.

wajouba

iTrader: (1)

how can I know whether my engine came from a 99 or 98 camaro? cause I saw the PCM pin outs before but didn't know which one to use... can you guide me on this?

oange ss

iTrader: (50)

does your ECT connector have 2 pins or 3 ?

wajouba

iTrader: (1)

whats an ect? :S pardon my dictionary of abbreviations

oange ss

iTrader: (50)

Engine Coolant Temp sensor, front sensor in the driver side head

wajouba

iTrader: (1)

it has 3, with the green that connects to the dash for reading of temp... but I heard 99s also have the 3 wired one... so what is mine 98 or 99?

oange ss

iTrader: (50)

only 98 has the 3 pin ECT sensor, 99+ coolant guages are PCM fed...so you have a 98 engine/harness

wajouba

iTrader: (1)

Alright, so I have a 98 harness and PCM, where is my serial data pin on the PCM?

oange ss

iTrader: (50)

C2 (blue connector) pin#58, purple wire

wajouba

iTrader: (1)

ok about the ground wires... both Chassis? or does one have to be from the ecu ground?

oange ss

iTrader: (50)

ALDL pin #4 chassis ground
pin #5 signal ground (ECU)

Speed Demon

iTrader: (14)

What is the difference between a signal ground and chassis ground?

I know what a chassis ground is.

wajouba

iTrader: (1)

I have the same question in mind... so is a signal ground a ground comming from the ECU/PCM or comming directly from the negative of the battery? (which is actually chassis I think)...

Speed Demon

iTrader: (14)

I know on the BMW DME (PCM) it has serveral grounds that are switched ground/open by the PCM to control relays. I see in the F-body PCM pinouts that is has several grounds, are some of these switched (or signal) grounds?

wajouba

iTrader: (1)

yeah for example the pin number 60, on the blue connecter right beside the Serial Data, is this what we call Signal Ground? :S