CHART A3
If code EO31 is stored hard along hard codes EO38 and EO59, this condition is probably caused by an open in ground circuit No. 476A for the MAP, MAT and transmission temperature sensors. To verify this condition, probe the following harness terminals with a voltmeter to 12 volts: MAT sensor pin "A". MAP sensor harness pin "A". Transmission temperature sensor pin "A".
If voltage is zero at sensors, check circuit No. 476A for an open. If wiring is okay, either the ECM connector or the ECM itself is faulty. If 12 volts is present at sensors, follow the diagnostic chart for each individual code. Diagnose code EO31 first, code EO38 second, and code EO59 last.
