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 4.8 volts at Wide Open Throttle (WOT).
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
TP sensor intermittently indicates a throttle position signal less than 0.1 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 Fail 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. |
| • | DTC can be cleared by using the scan tool Clear Info function or by disconnecting the PCM battery feed. |
Diagnostic Aids
Check for the following conditions:
| • | Poor connection at the PCM or sensor. |
| Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection using a male terminal perform drag test to verify correct terminal tension. |
| • | 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.
Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
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This step checks for conditions which may cause the DTC to set with a good heated oxygen sensor. Correct any of the described conditions if present.
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Before replacing the HO2S, check for silicon contamination. Refer to
Notice: Contamination of the oxygen sensor can result from the use of an inappropriate RTV sealant (not oxygen sensor safe) or excessive engine coolant or oil consumption. Remove the HO2S and visually inspect the portion of the sensor exposed to the exhaust stream in order to check for contamination. If contaminated, the portion of the sensor exposed to the exhaust stream will have a white powdery coating. Silicon contamination causes a high but false HO2S signal voltage (rich exhaust indication). The control module will then reduce the amount of fuel delivered to the engine, causing a severe driveability problem. Eliminate the source of contamination before replacing the oxygen sensor.
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Step | Action | Value(s) | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | ||||||||||
2 |
Important: If any DTCs are set (except P1133 or P1134), go to those DTCs before proceeding with this diagnostic table.
Does the scan tool indicate DTC failed this ignition? | -- | Go to Diagnostic Aids | |||||||||
3 |
Was a problem found? | -- | ||||||||||
Visually/physically inspect the following items:
Was a problem found in any of the above areas? | -- | |||||||||||
5 |
Does the scan tool indicate voltage near the specified value? | 450 mV | ||||||||||
6 |
Does scan tool indicate voltage less than the specified value? | 300 mV | ||||||||||
Replace the affected Heated Oxygen Sensor(s). Refer to Heated Oxygen Sensor Replacement . Is action complete? | -- | -- | ||||||||||
8 | Repair the condition as necessary. Is action complete? | -- | -- | |||||||||
9 | Repair open HO2S 1 low signal circuit or grounded HO2S 1 high signal circuit. Refer to Heated Oxygen Sensor Wiring Repairs in Wiring Systems. Is action complete? | -- | -- | |||||||||
10 | Repair open HO2S 1 high signal circuit or poor connections at the PCM. Refer to Heated Oxygen Sensor Wiring Repairs in Wiring Systems. Is action complete? | -- | -- | |||||||||
11 |
Does the scan tool indicate DTC failed this ignition? | -- | System OK |
