Engine Check Engine Light Unless Scanner Attached

SpeedLobo

Member
Dec 20, 2019
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USA
Hoping someone on the forum can help, this is a weird one. My 92 is throwing codes unless my scan tool is attached an on. When it throws codes they are for most of the sensors connected to terminal 46 on the EEC: TPS, ECT, ACT, etc. All of the sensors are new. The FI harness is new. The grounds are good. There is low voltage (~5.4) at two of the posts on the VIP port. The connector to the check engine light causes my Power Probe to beep intermittently but no voltage (or ground) indicated. Any ideas on what to check or test next? Could this be a bad EEC? Thank you!
 
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Mustang5L5

Put lubricant all over the balls
Mod Dude
Feb 18, 2001
36,540
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Unplug the ECU and test for continuity between pin 40, 60 and 46. If there is none, your pin 46 trace is likely fried
 
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