87 ranger 2.9 v6 auto 2 wd , diagnosing a electrical and possible computer control problem i found in the cluster that there was no check engine bulb none at all no receptacle and no bulb also the printed circuit wasnt even punched out for one , is this right or did someone change the cluster? its really freakng me out because i cant figure out why my diagnostic reader wont communicate with the processor......any help will be greatly appreciated....mike
got a problem
Aug 08, 2007
2 Replies
In 1987, there was no requirement for a check engine light.
The first requirements for onboard diagnostics were in 1988.
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Jeff
You are looking at an early EEC-IV. Those did not have a CEL. Diagnostics are rather limited - don't expect a lot. All the 'communication' between the test connector and the computer consists of grounding one pin and counting pulses coming out on another. If the engine is running at all, I would rather suspect your reader than the computer. Does it work on another vehicle? You don't really need a 'reader'. A paper clip and a test light accomplish exactly the same thing. Google archives of this group for details how to connect those.
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