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Home >> Cadillac >> 1990 >> Seville Base, 4T60/ME9 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> ECM Trouble Code Charts >> ECM Code EO38: Open Mat Sensor Circuit >> Note On Intermittents
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Note On Intermittents

Manipulate circuits No. 472 and 476 wiring, MAT connector, and ECM connector while observing ECM parameter ED05. If failure is induced, MAT will jump from its normal value to open signal circuit reading of -35°C to -40°C. If wiring and connectors are okay, substitute a known good sensor and retest.

Fig 1: ECM Code EO38 Circuit Diagram
G90F21720
Fig 2: ECM Code EO38 Flow Chart
G90I13712