24 TPS Does Not Agree With MAP - (P 0121)

24 TPS DOES NOT AGREE WITH MAP - (P 0121)

The Throttle Position Sensor (TPS) rationality test is actually two complete and sperate tests. The first test conditions are:

ENABLING CONDITIONS
- Powertrain Control Module (PCM) not in Manifold Absolute Pressure (MAP) limp-in
- PCM not in TPS limp-in
- Engine RPM indicating idle
- MAP sensor must be indicating that manifold pressure is greater than 4 in. of vacuum

The Malfunction Indicator Lamp (MIL) is illuminated and a Diagnostic Trouble Code (DTC) is stored in memory if the TPS voltage indicates wide open throttle (WOT) (greater than 3.75 volts) while the MAP sensor indicates an idle or light load condition. At barometric pressures below 27.56 in. of mercury, the test is very difficult to fail.

The second test condition is:

ENABLING CONDITIONS
- PCM not in MAP limp-in
- PCM not in TPS limp-in
- Engine RPM greater than idle
- Vehicle Speed Sensor (VSS) indicating that the vehicle is moving
- MAP sensor must be indicating that manifold pressure is less than 4 in. of vacuum

The MIL is illuminated and a DTC is stored in memory if the TPS voltage indicates idle (0.70 volt) while the other enabling conditions indicate a loaded cruise condition.

This malfunction could possibly be caused by problems with any of the following components:
- TPS
- TPS wiring (backwards)
- MAP sensor