Code 45, Idle Switch CKT/CKT Grounded Or MISADJUSTED TPS

This code is set if ECM senses an open switch or circuit at conditions above idle. When properly adjusted, the TPS idle switch pulls ECM circuit low (ground) when throttle is closed. If idle switch is measured separately, little or no resistance should be indicated. When throttle is opened, TPS idle switch pulls ECM circuit high. If idle switch is measured separately, infinite resistance should be indicated.

Code 45 will set when the following conditions are met for 5 seconds.

• TPS is greater than or equal to 30 degrees.
• Engine speed is greater than or equal to 2900 RPM.
• MAP sensor indicates more than 13 in. Hg.
• Idle is switch closed.

1. With throttle wide open, TPS idle switch should be open.
2. Checks for faulty TPS harness.
3. Checks for an open or short circuit, and/or faulty ECM.

Fig 1: Code 45 Flow Chart, Idle Switch Ckt./Ckt. Grounded Or Misadjusted TPS

Courtesy of GENERAL MOTORS CORP.

Fig 2: Code 45 Schematic, Idle Switch Ckt./Ckt. Grounded Or Misadjusted TPS

Courtesy of GENERAL MOTORS CORP.