Note On Intermittents

1991 Cadillac Seville STSSECTION Note On Intermittents

Manipulate circuits No. 472 and 476 wiring, MAT connector, and PCM connector while observing PCM 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: PCM Code EO38, Schematic, Open MAT Sensor Circuit
G91E07541
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.