Circuit Description
The throttle position (TP) sensors 1 and 2 are located within the throttle body assembly. Each sensor has its own 5-volt reference, low reference, and signal circuit. This provides the powertrain control module (PCM) with a signal voltage proportional to throttle plate movement. TP sensor 1 signal voltage at closed throttle is near the 5-volt reference and decreases as the throttle plate is opened. TP sensor 2 signal voltage at closed throttle is near the low reference and increases as the throttle plate is opened. When the PCM detects a fault with both TP 1 and TP 2 the diagnostic trouble code (DTC) sets.
Conditions for Running the DTC
| • | The ignition switch is in the crank or run position. |
| • | DTC P1635 is not set. |
| • | The ignition voltage is more than 5.23 volts. |
Conditions for Setting the DTC
The TP sensor 1 and 2 voltages are not within a calibrated range.
Action Taken When the DTC Sets
| • | The PCM will illuminate the malfunction indicator lamp (MIL) during the first trip in which the diagnostic runs and fails. |
| • | The PCM will store conditions which were present when the DTC set as Freeze Frame/Failure Records data. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn OFF the MIL during the third consecutive trip in which the diagnostic runs and passes. |
| • | The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | The DTC can be cleared by using a scan tool. |
Diagnostic Aids
The DTC indicates 2 separate faults, one fault with TP sensor 1 and one fault with TP sensor 2. The DTC P1120 diagnostic table along with the DTC P1220 diagnostic table may need to be followed to find both faults.
Step | Action | Yes | No |
|---|---|---|---|
1 | Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | |
2 |
Important: This DTC indicates 2 separate faults. One fault with TP sensor 1 and one fault with TP sensor 2. The DTC P1120 diagnostic table along with the DTC P1220 diagnostic table may need to be followed to find both faults. Are DTCs P1120 and P1220 set? | -- |
