To have 0 monitored Voltage (you didnt say whether you were checking REF or SIGNAL voltage) you would either have to have a open in the
A. Limiting resistor
B. ref circuit
C. signal circuit
D. short to ground in either ref or signal wire.
P0122 - Throttle Position (TP) sensor Circuit Low Input
The TP sensor circuit is monitored by the PCM for a low TP rotation angle (or voltage) input through the comprehensive component monitor (CCM). If during key ON engine OFF or key ON engine running the TP rotation angle (or voltage) changes below a minimum calibrated limit, the test fails.
· TP sensor not seated properly
· TP circuit open to PCM · VREF open to TP sensor · TP circuit short to GND ·
Damaged TP sensor ·
Damaged PCM
Fault exhibits a symptom of limited power.
A TP PID (TP V PID) reading less than 3.42% (0.17 volt) in key ON engine OFF, continuous memory or key ON engine running indicates a hard fault.
You should be getting a SES light. Probably have idle issues too.
If you have zero volts, either the meter is bad or your not reading the correct points.
There are several other TPS codes related to voltage issues. This is just one of them.