Throttle Position Switch: Testing and Inspection

Diagnostic Chart.:

ISC Circuit:

DISPLAY CONFIGURATION:

After the diagnostic trouble codes have been displayed, the Driver Information Center (DIC) will display "ECM?". Depress the HI blower button. The display will change to read "ECM DATA?". Depress the LO blower button. The display will change to read "ECM INPUTS?". Depress the HI blower button. The display will change to read EI70. Depress the LO blower button twice. The display will change to read LO '0' EI72. When the brake pedal is depressed and released the display will change to read HI 'X'. The change from '0' to 'X' indicates that the test has been successfully completed.

TEST DESCRIPTION:

This test detects the open and close of the nose switch of the Idle Speed Control (ISC) at terminal A7 of the PCM.

NOTES ON FAULT TREE:

1. HI indicates that the throttle nose switch is open. LO indicates that the switch is closed.

2. If the display remains LO '0', CKT 427 is shorted to ground or the PCM is bad. If the display changes to HI 'X', the ISC motor is bad. If the display remains HI '0', CKT 427 or CKT 450 is open.