Automatic Transmission

Inhibitor Switch Schematic:

A faulty inhibitor switch will set code 51 in the on-board diagnostic system. Refer to the schematic diagram and test the switch with the diagnostic chart.

Wire color code identification:

L: Blue
B: Black
Y: Yellow
G: Green
R: Red
W: White
Br: Brown
Lg: Light green
Gr: Gray

Inhibitor Switch Diagnostic Chart:

INHIBITOR SWITCH DIAGNOSTIC CHART

Inhibitor Switch Testing:

CHECK ECU VOLTAGE

With ignition "ON," measure voltage between ECU connector terminal and ground as follows:

Connector & terminal: Voltage: [1]
(B58)9-Ground 0V ("P" range)
(B58)9-Ground 8V min. (all except "P" range)

CHECK INHIBITOR SWITCH

1. Disconnect transmission connectors.
2. Measure resistance between inhibitor switch terminals while shifting select lever from "N" to any other position:

Connector & terminal: Resistance:
(E15)3-(E15)4 0 Ohms ("P" range)
1M Ohms min. (all except "P" range)

CHECK HARNESS BETWEEN ECU AND INHIBITOR SWITCH

1. Disconnect ECU and inhibitor switch connectors.
2. Measure resistance between ECU and inhibitor switch connectors and ground as follows:

Connector & terminal: Resistance:
(B58)9-(B15)3 0 Ohms
(B15)3-Ground 1M Ohms min.
(B15)4-Ground 0 Ohms