Code 45, Idle Switch CKT, CKT Grounded 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 45 will set when low voltage input at ECM is indicated with engine running off idle (greater than 2900 RPM) and MAP sensor reading is high for at least 5 seconds.

1. By disconnecting TPS, ECM should detect a high voltage signal and scan tester should indicate "OFF". This checks for a short to ground in the Blue/White wire.
2. This checks for a short to B+ in the Gray/Red wire, or a misadjusted or faulty TPS.