Question about the Check Engine Light
Thread Starter
Racer
Joined: May 2001
Posts: 472
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From: Tampa Bay Area
Question about the Check Engine Light
As many of you know I have a somewhat custom application. Well I am finally getting around to wiring in the check engine light and ALDL connector. However I can not get the check engine light to work at all. The wiring diagram that I have shows that it connects to pin B5, but that wire also goes to the Distributor connector and is purple-white. Is there something that I am missing? Does it have to connect to something else first. I am sure that it has to go through the dash harness first, but I don't have that nor do I have the wiring diagram for that. Any help at all would be great.
Thanks,
Thanks,
Team Owner
Joined: Dec 2000
Posts: 90,675
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From: SE NY
Cruise-In II Veteran
With my '88 these signals are:
- "Dist Ref" signal comes in on the Ppl/Wht wire to ECM pin B5;
- "Service Engine Soon" light control goes out on the Brn/Wht wire from ECM pin A5.
- "Dist Ref" signal comes in on the Ppl/Wht wire to ECM pin B5;
- "Service Engine Soon" light control goes out on the Brn/Wht wire from ECM pin A5.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
I also have a GM Shop Manual for an '85 Vette and it shows the same ECM pin & wire color for the "Check Engine Control" function. Here too pin B5 is used for "EST Ref", the same function as on my '88.
So, indeed, it looks like connecting the SES light to ECM pin A5 will give you normal control over it.
So, indeed, it looks like connecting the SES light to ECM pin A5 will give you normal control over it.
Thread Starter
Racer
Joined: May 2001
Posts: 472
Likes: 0
From: Tampa Bay Area
Originally Posted by 65Z01
I also have a GM Shop Manual for an '85 Vette and it shows the same ECM pin & wire color for the "Check Engine Control" function. Here too pin B5 is used for "EST Ref", the same function as on my '88.
So, indeed, it looks like connecting the SES light to ECM pin A5 will give you normal control over it.
So, indeed, it looks like connecting the SES light to ECM pin A5 will give you normal control over it.
Thanks
Josh
Safety Car
Joined: Dec 2002
Posts: 3,655
Likes: 24
From: Charleston SC
I had similar problems when I installed a LT1 into my 84 and using the corvette fuel injection book, by Charles Probst, I was able to have everything work perfect.
Acourding to my corvette fuel injection book The ALDL should be as follows
ECM_____ALDL
Pin A8___Pin E Serial Data (Also shows a wire going to the IP)
Pin A9___Pin B
Pin D3___Pin A System Gnd (Gnd is parallel between ECM and ALDL)
ALDL pin G goes t Fuel pump relay pin D
Pin A5 goes to the SES lamp (Provides ground)
to test this just ground the wire from the SES lamp and it should light
As others have stated ECM pin B5 goes to distributor wire B ( Reference)
Here is a link for the ALDL side of the thing
http://www.akmcables.com/techinfo.htm
Acourding to my corvette fuel injection book The ALDL should be as follows
ECM_____ALDL
Pin A8___Pin E Serial Data (Also shows a wire going to the IP)
Pin A9___Pin B
Pin D3___Pin A System Gnd (Gnd is parallel between ECM and ALDL)
ALDL pin G goes t Fuel pump relay pin D
Pin A5 goes to the SES lamp (Provides ground)
to test this just ground the wire from the SES lamp and it should light
As others have stated ECM pin B5 goes to distributor wire B ( Reference)
Here is a link for the ALDL side of the thing
http://www.akmcables.com/techinfo.htm
