Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptor
DTC P0120: Throttle Position (TP) Sensor 1 CircuitDTC P0220: Throttle Position (TP) Sensor 2 Circuit
Diagnostic Fault Information
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
|---|---|---|---|---|---|
TP Sensor 1 Signal | P0120, P0122 | P2135 | P0120, P0122 | P0120, P0123 | P0068, P0121 |
TP Sensor 1 5-Volt Reference | P0120, P0122 | P2135 | P0120, P0122 | P0120, P0123 | -- |
TP Sensor 1 Low Reference | -- | P2135 | P0120, P0123 | -- | -- |
TP Sensor 2 Signal | P0220, P0222 | P2135 | P0220, P0223 | P0220, P0223 | P0068, P0121 |
TP Sensor 2 5-Volt Reference | P0220, P0222 | P2135 | P0220, P0222 | P0220, P0223 | -- |
TP Sensor 2 Low Reference | -- | P2135 | P0220, P0223 | -- | -- |
Typical Scan Tool Data
Circuit | Normal Range | Short to Ground | Open or High Resistance | Short to Voltage |
|---|---|---|---|---|
TP Sensor 1 Signal | 0.27-4.67 V | 0 V | 0 V | 5 V |
TP Sensor 1 5-Volt Reference | 0.27-4.67 V | 0 V | 0 V | 5 V |
TP Sensor 1 Low Reference | 0.27-4.67 V | -- | 5 V | -- |
TP Sensor 2 Signal | 0.31-4.7 V | 0 V | 5 V | 5 V |
TP Sensor 2 5-Volt Reference | 0.31-4.7 V | 0 V | 0 V | 5 V |
TP Sensor 2 Low Reference | 0.31-4.7 V | -- | 5 V | -- |
Circuit/System Description
The throttle actuator control (TAC) system uses 2 throttle position (TP) sensors to monitor the throttle position. The TP sensors 1 and 2 are located within the throttle body assembly. Each sensor has the following circuits:
| • | A 5-volt reference circuit |
| • | A low reference circuit |
| • | A signal circuit |
Two processors are also used to monitor the TAC system data. Both processors are located within the powertrain control module (PCM). Each signal circuit provides both processors with a signal voltage proportional to throttle plate movement. Both processors monitor each other's data to verify that the indicated TP calculation is correct.
Conditions for Running the DTC
| • | The system voltage is more than 5.23 volts. |
| • | The ignition is in Unlock/Accessory or Run position. |
Conditions for Setting the DTC
The indicated TP calculation between the processors does not agree.
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame and/or the Failure Records. |
| • | The control module commands the TAC system to operate in the Reduced Engine Power mode. |
| • | A message center or an indicator displays Reduced Engine Power. |
| • | Under certain conditions the control module commands the engine OFF. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
Scan Tool Reference
Circuit/System Verification
| • | Ignition ON, use a scan tool to observe the TP sensor 1 voltage with the accelerator pedal in the rest position. Voltage should be between 0.27-4.67 volts. |
| • | With the ignition ON, observe the TP sensor 2 voltage with the accelerator pedal in the rest position with a scan tool. Voltage should be between 0.31-4.7 volts. |
Circuit/System Testing
- Clear DTCs with the scan tool. Operate the vehicle within the Conditions for Running the DTC or within the conditions that you observed from the Freeze Frame/Failure Records.
- Ignition ON, use a scan tool to observe the TP sensor 1 voltage with the accelerator pedal in the rest position. Voltage should be between 0.27-4.67 volts.
- With the ignition ON, observe the TP sensor 2 voltage with the accelerator pedal in the rest position with a scan tool. Voltage should be between 0.31-4.7 volts.
- Ignition ON, use a scan tool to observe the DTCs.
- Disconnect the throttle body harness connector and verify the scan tool TP sensor 1 voltage is less than 0.1 volt.
- With the throttle body harness connector still disconnected, verify the scan tool TP sensor 2 voltage is more than 4.8 volts.
- Ignition ON, test for 4.8-5.2 volts between both 5-volt reference circuits and the negative terminal of the battery.
- Install a 3A fused jumper wire between the signal circuit and the 5-volt reference circuit of the TP sensor 1 and verify the TP sensor 1 voltage is more than 4.8 volts.
- Install a test lamp between the signal circuit and the negative terminal of the battery of the TP sensor 2 and verify the TP sensor 2 voltage is less than 0.1 volt.
- If all circuits test normal, replace the throttle body.
| ⇒ | If more than 4.67 volts, test the low reference for an open. If the circuit tests normal, replace the control module. |
| ⇒ | If less than 0.27 volt, test the TP sensor 1 signal circuit for a short to ground. If the circuit tests normal, replace the control module. |
| ⇒ | If more than 4.7 volts, test the low reference for an open. If the circuit tests normal, replace the control module. |
| ⇒ | If less than 0.31 volt, test the TP sensor 2 signal circuit for a short to ground. If the circuit tests normal, replace the control module. |
| ⇒ | If DTC P0120 is the only code set, replace the PCM. |
| ⇒ | If DTC P0220 is the only code set, replace the PCM. |
| ⇒ | If any other codes are set, refer to that code first . Refer to Diagnostic Trouble Code (DTC) List - Vehicle . |
| ⇒ | If more than 0 volt, test the TP sensor 1 signal circuit for a short to voltage. If the circuit tests normal, replace the control module. |
| ⇒ | If less than 4.8 volts, test the TP sensor 2 signal circuit for a short to ground. If the circuit tests normal, replace the control module. |
| ⇒ | If more than 5.2 volts, test both 5-volt reference circuits for a short to voltage. If the circuit tests normal, replace the control module. |
| ⇒ | If less than 4.8 volts, test both the 5-volt reference circuits for an open or short to ground. If the circuit tests normal, replace the control module. |
| ⇒ | If less than 4.8 volts, test the TP sensor 1 signal circuit for an open. If the circuit tests normal, replace the control module. |
| ⇒ | If more than 0.1 volt, test the TP sensor 2 signal circuit for an open. If the circuit tests normal, replace the control module. |
| ⇒ | If test lamp illuminates, test the TP sensor 2 signal circuit for a short to voltage. If the circuit tests normal, replace the control module. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for PCM replacement, setup, and programming
