The throttle position sensor (TPS) is directly connected to the throttle valve shaft. The ECM sends a voltage signal to the potentiometer-type sensor and monitors the voltage that comes back.

Resistances decreases (voltage increases) as the throttle opens. Check throttle position sensor function by disconnecting the harness connector and checking continuity across the terminals while changing the throttle position. If the results are incorrect, replace the throttle position sensor. The sensor is not adjustable.

M50 and M60 engines

1. test conditions

harness connector disconnected,ignition on

2. terminals

1+ ground in harness connection

3. voltage

5 VCD approx.

1. harness connector disconnected, ignition off

2. 1 and 3 at sensor terminals

3. 4.0 kohms approx.

1. throttle plate rotated from idle to full throttle position

2. 1 and 2 at sensor terminals

3. continuously variable from 1.0 - 4 kohms (approx.) without interruption