EGR Problem

1995 Chevrolet Forward Control 4.3 Z, AutomaticSECTION EGR Problem

EGR valve sticking open at idle is usually accompanied by a rough idle and/or stalling. If Code 45 is intermittent, see INTERMITTENTS in TESTS W/O CODES - GASOLINE article.

CODE 45 TERMINAL & CIRCUIT WIRING IDENTIFICATION

Application ECM/PCM Terminal Wire Color
"C" & "K" Series
4.3L
Oxygen Sensor Signal A10 Purple
Oxygen Sensor Ground A12 Tan
"G" Series
4.3L A/T
Oxygen Sensor Signal A10 Purple
Oxygen Sensor Ground A12 Tan
"L" & "M" Series
4.3L
Oxygen Sensor Signal A10 Purple
Oxygen Sensor Ground A12 Tan
"P" Series
4.3L
Oxygen Sensor Signal A10 Purple
Oxygen Sensor Ground A12 Tan
"S" & "T" Series
4.3L (VIN W) Pickup & A/T Utility
Oxygen Sensor Signal A10 Purple
Oxygen Sensor Ground A12 Tan
4.3L (VIN Z) A/T Pickup
Oxygen Sensor Signal A10 Purple
Oxygen Sensor Ground A12 Tan
Fig 1: Code 45 Schematic (4.3L) Rich Exhaust Indication
G91H07378
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.