Code 44, Idle Switch CKT/Open CKT Or MISADJUSTED TPS

Code 44 will set if ECM senses an open circuit at idle conditions. Idle switch is used to inform ECM whether throttle is closed, or in idle position. When TPS is properly adjusted, a closed throttle switch will pull ECM circuit low (ground) through TPS idle switch. ECM will store Code 44. However, ECM will not reactivate CHECK ENGINE light for this malfunction.

Code 44 will set if engine RPM is less than 1000 and idle switch is open. Both conditions must exist for 10 seconds.

1. Applying vacuum to throttle opener will ensure throttle will be in idle position. Resistance should be 500 ohms or less at idle. An open circuit should be present at WOT. A misadjusted TPS can keep idle switch open at closed throttle applications.
2. TPS checked okay in step 1). This step checks for an open circuit or faulty ECM.

Fig 1: Code 44 Flow Chart, Idle Switch Ckt./Open Ckt. or Misadjusted TPS

Courtesy of GENERAL MOTORS CORP.

Fig 2: Code 44 Schematic, Idle Switch Ckt./Open Ckt. or Misadjusted TPS

Courtesy of GENERAL MOTORS CORP.