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 1 volt at closed throttle to 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. If the PCM detects a TP signal voltage that is intermittently less than the range of the TP sensor, DTC P1122 will be set.
Conditions for Setting the DTC
| • | The ignition is ON. |
| • | TP sensor intermittently indicates a throttle position signal less than 0.15 volt. |
Action Taken When the DTC Sets
| • | The PCM will not illuminate the malfunction indicator lamp (MIL). |
| • | The PCM will store conditions which were present when the DTC set as Failure Records data only. This information will not be stored as Freeze Frame data. |
Conditions for Clearing the MIL/DTC
| • | A 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 Clear Info function. |
Diagnostic Aids
Check for the following conditions:
| • | Poor connection at the PCM or the TP sensor |
| 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 P1121 cannot be duplicated, reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | ||
2 | Select DTC info, Last Test Fail on the scan tool. Is DTC P0122 also set? | -- | Go to DTC P0122 Throttle Position (TP) Sensor Circuit Low Voltage | |
3 | Is DTC P1107 also set? | -- | ||
4 | Check for a poor 5 volt reference A circuit or TP signal circuit terminal connection at the TP sensor. Was a problem found? | -- | ||
5 | Check the TP signal circuit between the TP sensor connector and the PCM for an intermittent open or short to ground. Was a problem found? | -- | ||
6 | Check for an intermittent short to ground on the 5 volt reference A circuit between the PCM and the following components:
Was a problem found? | -- | ||
7 | Check for a poor 5 volt reference A circuit terminal connection at the PCM. Was a problem found? | -- | ||
8 | Check for an intermittent open in the 5 volt reference A circuit. Refer to Troubleshooting Procedures in Electrical Diagnosis. Was a problem found? | -- | Go to Diagnostic Aids | |
9 | Replace the harness connector terminal(s) for the 5 volt reference A circuit and/or the TP signal circuit as necessary. Refer to Repair Procedures in Electrical Diagnosis. Is action complete? | -- | -- | |
10 | Repair intermittent open/short circuit in wiring harness as necessary. Refer to Repair Procedures in Electrical Diagnosis. Is action complete? | -- | -- | |
11 |
Does the scan tool indicate DTC P1122 failed? | -- | System OK |
