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 A/T ⁽¹⁾

Oxygen Sensor Signal

C14

Purple

Oxygen Sensor Ground

C13

Tan

2.5L, 2.8L, 3.1L & "C", "K" & "P" Series 4.3L ⁽¹⁾ & V8 (All With M/T)

Oxygen Sensor Signal

Purple

Oxygen Sensor Ground

Tan

3.8L

Oxygen Sensor Signal

BD3

Purple

Oxygen Sensor Ground

BD2

Tan

4.3L ⁽¹⁾ "S" & "T" Series Pickup With M/T

Oxygen Sensor Signal

Purple

Oxygen Sensor Ground

Tan

4.3L ⁽¹⁾ "S" & "T" Series Utility Vehicles With Man. Trans. & All Models With 4L60-E A/T ⁽¹⁾

Oxygen Sensor Signal

A10

Purple

Oxygen Sensor Ground

A12

Tan

4.3L ⁽¹⁾ Turbo

Oxygen Sensor Signal

GE14

Purple

Oxygen Sensor Ground

GE15

Tan

⁽¹⁾	The 4.3L oxygen sensor has 3 wires: sensor signal, common ground and heating element.

Fig 1: CODE 13, Schematic, Oxygen Sensor Circuit

Fig 2: CODE 13, Flowchart, Oxygen Sensor Circuit