Diagnostic Aids

WARNING: This page is about a different car, the 1993 Pontiac Grand Prix, 1993 Pontiac Firebird, 1993 Oldsmobile Cutlass Supreme, 1993 Chevrolet Lumina, and 1993 Chevrolet Camaro. However, it is still accessible from the selected car via links, so may be relevant.

Control module will not go into closed loop if Code 13 is set. Code 13 may set if vehicle runs out of fuel or stalls while vehicle is in motion. If oxygen sensor ground becomes loose, a false oxygen sensor reading will occur. This can result in a Code 13 being set. On models equipped with an oxygen sensor heating element, element resistance should be 3.5-14 ohms.

CODE 13 ECM TERMINAL & CIRCUIT WIRING IDENTIFICATION

Application	ECM Terminal	Wire Color
3.4L (VIN S) "W " Body
O2 Signal	B21	Purple
O2 Ground	B20	Tan
3.4L (VIN S) "F" Body
Left O2 Signal	B21	Purple/White
Left O2 Ground	B20	Black/White
Right O2 Signal	B22	Purple
Right O2 Ground	B23	Black/White

Fig 1: Code 13 Schematic (All Models) Open Oxygen Sensor Circuit

Fig 2: Code 13 Flow Chart (All Models) Open Oxygen Sensor Circuit