Throttle Position Sensor: Testing and Inspection

Throttle Sensor Schematic:

A faulty throttle sensor will set code 31 in the on-board diagnostic system. Refer to the schematic diagram and test the sensor 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

Throttle Sensor Diagnostic Chart:

THROTTLE SENSOR DIAGNOSTIC CHART


CHECK ECU VOLTAGE

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

Connector & terminal: Voltage:
(B58)2-Ground 4.7V (throttle fully closed)
1.6V (throttle fully open)
(B58)3-Ground 5V
(B58)1-Ground 0V

Throttle Sensor Testing:

CHECK THROTTLE SENSOR

1. Disconnect throttle sensor connector.
2. Measure resistance between sensor terminals #2 and #3. It should read 12K Ohms.
3. Measure resistance between terminals while slowly moving throttle from "closed" to "open:"

Terminal: Resistance:
#2-#4 1K Ohms (throttle fully closed)
4.3K Ohms (throttle fully open)

NOTE: Check that resistance increases smoothly as throttle is opened.

CHECK HARNESS BETWEEN ECU AND THROTTLE SENSOR

1. Disconnect ECU and throttle sensor connectors.
2. Measure resistance between ECU and sensor connectors as follows:

Connector & terminal: Resistance:
(B58)1-(E8)2 0 Ohms
(B58)2-(E8)4 0 Ohms
(B58)3-(E8)3 0 Ohms

3. Measure resistance between throttle sensor connectors and ground as follows:

Connector & terminal: Resistance:
(E8)2-Ground 1M Ohms min.
(E8)4-Ground 1M Ohms min.
(E8)3-Ground 1M Ohms min.