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Diagnostic Aids

Verify a clean, tight connection for ground circuit No. 413. An open circuit at sensor signal terminal or ground terminal will result in a Code 13.

CODE 13 ECM TERMINAL & CIRCUIT WIRING IDENTIFICATION

Application ECM Terminal Wire Color
All With 4L80-E Transmission
Oxygen Sensor Signal C14 Purple
Oxygen Sensor Ground C13 Tan
All Others
Oxygen Sensor Signal D7 Purple
Oxygen Sensor Ground D6 Tan
Fig 1: Code 13 Schematic (Except 4.3L Turbo) Open Oxygen Sensor Circuit
G91H07378
Fig 2: Code 13 Flow Chart (Except 4.3L Turbo) Open Oxygen Sensor Circuit
G91B07281