1987 tbi obd check no response / no code 12?? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

olllie · 02-06-2013, 01:57 AM

hi guys, Im lost and need some advice..

trying to check stored codes in my 87 1500 5.7 700r, jumped a and b with key off turned key on and i have no blinks. good obd ground and 5v.

When I set timing and disconnect the base idle connector the service engine soon light seems to work, and i have seen it light up for what I think is an egr code. But its very rare that the light turns on. I have had no egr for months.

Can't seem to be able to get any flashes, no 12 or any blinks at all. Any ideas where to start with this problem???

thanks!!

rfmaster · 02-06-2013, 12:07 PM

Check continuity from ALDL ground terminal (Pin A) to ECM connector A12 - system ground (Black/White wire Circuit #450). In the highly unlikely case you may have a broken crimp in ECM interface pin A12. Circuit 450 is shared ground circuit, but it is used with ECM internal ground reference for SES light and ALDL connector.

olllie · 02-06-2013, 12:11 PM

I will start there, thanks RF your the man!!

f.monroe · 02-06-2013, 12:18 PM

Look at the all connector real close and make sure it isn't upside down for some reason. I have also made the mistake of jumping the wrong pins before.
Frank
Posted via Mobile Device

02-06-2013, 01:57 AM	#1
olllie Registered User Join Date: Oct 2012 Location: BC Canada Posts: 65	1987 tbi obd check no response / no code 12?? hi guys, Im lost and need some advice.. trying to check stored codes in my 87 1500 5.7 700r, jumped a and b with key off turned key on and i have no blinks. good obd ground and 5v. When I set timing and disconnect the base idle connector the service engine soon light seems to work, and i have seen it light up for what I think is an egr code. But its very rare that the light turns on. I have had no egr for months. Can't seem to be able to get any flashes, no 12 or any blinks at all. Any ideas where to start with this problem??? thanks!!

02-06-2013, 12:07 PM	#2
rfmaster Registered User Join Date: Oct 2003 Location: OC CA Posts: 1,374	Re: 1987 tbi obd check no response / no code 12?? Check continuity from ALDL ground terminal (Pin A) to ECM connector A12 - system ground (Black/White wire Circuit #450). In the highly unlikely case you may have a broken crimp in ECM interface pin A12. Circuit 450 is shared ground circuit, but it is used with ECM internal ground reference for SES light and ALDL connector. __________________ "The Beast" 1975 Chevrolet C20 longbed 350/700R4! with 3inch body lift Dual Flowmasters Super 40's! TBI retrofit completed (2007-07-29) New 383CID (+030) 08-304-8 9.5:1CR x36,005 (2012-12-17)

02-06-2013, 12:11 PM	#3
olllie Registered User Join Date: Oct 2012 Location: BC Canada Posts: 65	Re: 1987 tbi obd check no response / no code 12?? I will start there, thanks RF your the man!!

02-06-2013, 12:18 PM	#4
f.monroe Senior Member Join Date: May 2004 Location: Caldwell,Tx. Posts: 3,648	Re: 1987 tbi obd check no response / no code 12?? Look at the all connector real close and make sure it isn't upside down for some reason. I have also made the mistake of jumping the wrong pins before. Frank Posted via Mobile Device __________________ Born and proudly residing in a Red State !



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