Circuit Description
The Throttle Position (TP) sensor provides a voltage signal that changes relative to the throttle blade. Signal voltage will vary from about 0.5 volt at idle to about 5.0 volts at wide open throttle.
The TP sensor signal is one of the most important inputs used by the ECM for fuel control and for most of the ECM control outputs.
Conditions for Setting the DTC
| • | Engine running |
| • | TP sensor signal voltage less than about 0.2 volt for 3 seconds |
Action Taken When the DTC Sets
The Malfunction Indicator Lamp (MIL) will illuminate. The system will go Open Loop.
Conditions for Clearing the MIL/DTC
The conditions for the fault are no longer present and 50 ignition cycles have passed with no further faults or the ignition switch is turned OFF and the battery feed voltage is removed for 10 seconds.
Diagnostic Aids
A scan tool reads the throttle position in volts. The scan tool should read about 0.45 to 1.25 volts with throttle closed and the ignition ON or at idle. The voltage should increase at a steady rate as the throttle is moved toward WOT.
An open or a short to ground in 5 volt reference TP signal circuit or 417 will result in a DTC 22.
Refer to Intermittent Conditions .
Scan TP sensor while depressing the accelerator pedal with engine stopped and the ignition ON. Display should vary from below 0.95 volt when throttle was closed, to over 4.5 volts when throttle is held at wide open throttle position.
Test Description
The numbers below refer to the step numbers on the Diagnostic Table.
-
This step checks to see if DTC was set as result of a hard failure or intermittent condition.
-
This test simulates DTC 21 (high voltage). If the ECM recognizes the high signal voltage the ECM and wiring are OK.
-
This test simulates a high signal voltage to check for an open in the TP signal circuit.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the On-Board Diagnostic (OBD) System Check? | -- | ||
Does the scan tool display the Throttle Position (TP) sensor voltage at or less than the specified value? | 0.2 V (200 mV) | Go to Diagnostic Aids | ||
Does the scan tool display the Throttle Position sensor voltage greater than the specified value? | 4.0 V (4,000 mV) | |||
Probe the TP sensor signal circuit with a test lamp connected to B+. Does the scan tool display the Throttle Position sensor voltage greater than the specified value? | 4.0 V (4,000 mV) | |||
5 |
Did you find a problem? | -- | ||
6 |
Did you find a problem? | -- | ||
7 |
Did you find aa problem found? | -- | ||
8 | Replace the ECM. Refer to Engine Control Module Replacement . Is the action complete? | -- | -- | |
9 |
Did you find a problem? | -- | ||
10 | Replace the TP sensor. Refer to Throttle Position Sensor Replacement Is the action complete? | -- | -- | |
11 |
Was a problem found? | -- | ||
12 |
Did you find a problem? | -- | ||
13 |
Did you find a problem? | -- | ||
14 |
Did you find a problem? | -- | ||
15 |
Did the DTC reset? | -- | ||
16 | Are any DTCs stored which you have not diagnosed? | -- | Go to the Applicable DTC Table | System OK |
