Circuit Description
The Throttle Position (TP) sensor circuit provides a voltage signal that changes relative to throttle blade angle. The signal voltage will vary from less than 1 volt at closed throttle to above 4 volts at Wide Open Throttle (WOT). The TP signal is one of the most important inputs used by the PCM for fuel control and most of the PCM-controlled outputs.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
| • | TP sensor signal voltage is less than 0.1 volt. |
| • | Above conditions are present for longer than 5 seconds. |
Action Taken When the DTC Sets
| • | The PCM will illuminate the malfunction indicator lamp (MIL) during the first trip in which the diagnostic test has been run and failed. |
| • | The PCM will store conditions which were present when the DTC set as Freeze Frame and 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 has been run and passed. |
| • | The History DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | The DTC can be cleared by using the scan tool. |
Diagnostic Aids
Check for the following conditions:
| • | Poor connection at PCM. |
| Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection |
| • | Damaged harness. |
| Inspect the wiring harness for damage. If the harness appears to be OK, observe the throttle position display on the scan tool while moving connectors and wiring harnesses related to the TP sensor. A change in the display will indicate the location of the malfunction. |
If DTC P0122 cannot be duplicated, the information included in the Fail Records data can be useful in determining vehicle mileage since the DTC was last set. If it is determined that the DTC occurs intermittently, performing the DTC P1122 Diagnostic Table may isolate the cause of the malfunction.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming .
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | ||
2 |
Is the TP Sensor below the specified value? | 0.1V | ||
3 |
Does scan tool indicate DTC P0122 failed this ignition? | -- | Go to Diagnostic Aids | |
4 |
Is the measured voltage near the specified value? | 5.0V | ||
5 | Is DTC P1635 also set? | -- | ||
6 | Probe the sensor ground circuit at the TP sensor connector with a test light connected to battery positive. Is the light on? | -- | ||
7 | Connect the 5 volt reference and the signal circuits together with a fused jumper at the TPS harness connector. Is the TPS voltage shown on the scan tool near the specified value? | 5.0V | ||
8 | Check the TPS signal circuit for a poor connection at the PCM and replace terminals if necessary. Refer to Repairing Connector Terminals in Wiring Systems. Was a repair necessary? | -- | ||
9 | Check the TP reference circuit for an open or short to ground and repair as necessary. Refer to Wiring Repairs in Wiring Systems. Was a repair necessary? | -- | ||
10 | Check the TP sensor signal circuit for an open or a short to ground and repair as necessary. Refer to Wiring Repairs in Wiring Systems. Was a repair necessary? | -- | ||
11 | Check for a poor connection at the TP sensor harness connector and replace terminals if necessary. Refer to Repairing Connector Terminals in Wiring Systems. Was a repair necessary? | -- | ||
|
Important: : Replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Replace the PCM. Is the action complete? | -- | -- | ||
13 | Replace TP sensor. Refer to Throttle Position Sensor Replacement . Is action complete? | -- | -- | |
14 |
Does the scan tool indicate DTC P0122 failed? | -- | System OK |
