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Home >> GMC >> 1987 >> Forward Control 4.8 T, Automatic, 400/M40 >> Repair and Diagnosis >> External Pages >> Different car >> Section 16 (Engine Controls - Tests W/Codes - 5.7L) >> Trouble Code Charts >> Code 13, Open Oxygen Sensor Circuit >> Diagnostic Aids

Diagnostic Aids

WARNING: This page does not describe the selected car, but rather 20 other vehicles, including the 1994 GMC Yukon, 1994 GMC Vandura Special, 1994 GMC Vandura, 1994 GMC Suburban, and 1994 GMC Rally Camper Special. However, it is still accessible from the selected car via links, so may be relevant.

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