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Home >> GMC >> 1994 >> Forward Control 7.4 N >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - 5.7L >> Trouble Code Charts >> Code 13, Open Oxygen Sensor Circuit >> Diagnostic Aids
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Diagnostic Aids

Verify a clean, tight connection for the sensor ground. An open circuit at sensor signal terminal or ground terminal will result in a Code 13.

CODE 13 TERMINAL & CIRCUIT WIRING IDENTIFICATION

Application PCM Terminal Wire Color
"C" & "K" Series
5.7L A/T
Oxygen Sensor Signal A10 Purple
Oxygen Sensor Ground A12 Tan
5.7L M/T
Oxygen Sensor Signal D7 Purple
Oxygen Sensor Ground D6 Tan
"G" Series
5.7L A/T
Oxygen Sensor Signal A10 Purple
Oxygen Sensor Ground A12 Tan
"P" Series
5.7L A/T
Oxygen Sensor Signal A10 Purple
Oxygen Sensor Ground A12 Tan
5.7L M/T
Oxygen Sensor Signal D7 Purple
Oxygen Sensor Ground D6 Tan
Fig 1: Code 13 Schematic (5.7L) Open Oxygen Sensor Circuit
G91H07378
Fig 2: Code 13 Flow Chart (5.7L) Open Oxygen Sensor Circuit
G91B07281