Code 44, Idle Switch Circuit, Open Circuit Or MISADJUSTED TPS: Notes

The Throttle Position Sensor (TPS) has an idle switch that sends a signal to ECM. ECM applies 5 volts to idle switch. The idle switch is closed with engine at idle (low voltage signal to ECM) and open with engine off idle (high voltage signal at ECM).

Code 44 will set when high voltage input at ECM is indicated with the engine running at idle (less than 1000 RPM).

1. By jumpering TPS sensor terminals, ECM should detect a low voltage signal and scan tester should indicate "ON". This determines whether problem is in the wiring, ECM or a misadjusted or faulty TPS.
2. This step checks Gray/Yellow and Blue/White wires for an open, and for a faulty ECM.