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 Descriptors
DTC P0120: Throttle Position (TP) Sensor 1 CircuitDTC P0121: Throttle Position (TP) Sensor 1 Performance
DTC P0122: Throttle Position (TP) Sensor 1 Circuit Low Voltage
DTC P0123: Throttle Position (TP) Sensor 1 Circuit High Voltage
DTC P0220: Throttle Position (TP) Sensor 2 Circuit
DTC P0222: Throttle Position (TP) Sensor 2 Circuit Low Voltage
DTC P0223: Throttle Position (TP) Sensor 2 Circuit High Voltage
DTC P2135: Throttle Position (TP) Sensor 1-2 Correlation
Diagnostic Fault Information
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
|---|---|---|---|---|---|
5-Volt Reference | * | -- | P0120, P0121, P0122, P0220, P0222, P2135 | P0121, **P0606 | -- |
TP Sensor 1 Signal | P0121, P0122 | P2135 | P0121, P0123 | **P0123 | P2135 |
TP Sensor 2 Signal | P0121, P0222 | P2135 | P0121, P0223 | **P0223 | P2135 |
Low Reference | -- | P2135 | P0120, P0123, P0220, P0223, P2135 | -- | -- |
*The vehicle may not start, not run, or stall **Internal PCM or TP sensor damage may occur if the circuit is shorted to B+ | |||||
Typical Scan Tool Data
Circuit | Short to Ground | Open | Short to Voltage |
|---|---|---|---|
Operating Conditions: The engine coolant temperature is greater than 70°C (158°F) and the ignition is ON with the engine is OFF. Parameter Normal Range: TP Sensor 7-21%/0.7-0.9 volts | |||
5-Volt Reference | * | 2%/0.1 Volts | -- |
TP Sensor 1 Signal | 2%/0.1 Volts | 99%/5.0 Volts | 99%/5.0 Volts |
Low Reference | -- | 99%/5.0 Volts | -- |
*No communication with scan tool | |||
Circuit | Short to Ground | Open | Short to Voltage |
|---|---|---|---|
Operating Conditions: The engine coolant temperature is greater than 70°C (158°F) and the ignition is ON with the engine is OFF. Parameter Normal Range: TP Sensor 2 45-55%/2.3-2.4 volts | |||
5-Volt Reference | * | 2%/0.1 Vvolts | -- |
TP Sensor 2 Signal | 2%/0.1 Vvolts | 99%/5.0 Volts | 99%/5.0 Volts |
Low Reference | -- | 99%/5.0 Volts | -- |
*No communication with scan tool | |||
Circuit/System Description
The TP sensor used with the throttle actuator control (TAC) system is actually a Hall Effect switch. The Hall Effect switch is surrounded by a magnetic yoke that induces a flux in the magnetic field when the throttle shaft is rotated. The PCM provides a 5-volt reference voltage to the sensor circuits in the TAC module. An integrated circuit (IC) receives and converts the magnetic pulses into two separate TP signal, each with their own characteristics. The TP sensor 1 output provides the powertrain control module (PCM) with a signal voltage that is proportional to the throttle plate movement. Both TP sensor signal voltages are low at closed throttle and increase as the throttle opens. TP sensor 1 determines the actual throttle valve position. TP sensor 2 has a voltage that is more than twice that of TP sensor 1 at idle. TP sensor 2 provides a backup value for TP sensor 1.
Conditions for Running the DTC
| • | The ignition is ON or the engine is running. |
| • | The DTCs runs continuously when the above condition is met. |
Conditions for Setting the DTC
P0120
| • | The PCM detects that the TP sensor 1 voltage is less than 0.5 volts. |
| OR |
| • | The PCM detects that the TP sensor 1 voltage is more than 4.5 volts. |
P0121
| • | The difference between the TP sensor 1 and the TP sensor 2 voltage is less than 0.8 volts. |
| OR |
| • | The difference between the TP sensor 1 and the TP sensor 2 voltage is more than 1.6 volts. |
P0122
The PCM detects that the TP sensor 1 voltage is less than 0.2 volts.
P0123
The PCM detects that the TP sensor 1 voltage is more than 4.5 volts.
P0220
| • | The PCM detects that the TP sensor 2 voltage is less than 0.5 volts. |
| OR |
| • | The PCM detects that the TP sensor 2 voltage is more than 4.8 volts. |
P0222
The PCM detects that the TP sensor 2 voltage is less than 0.5 volts.
P0223
The PCM detects that the TP sensor 2 voltage is more than 4.8 volts.
P2135
| • | The PCM detects that the difference between TP sensor 1 and TP sensor 2 is less than 0.2 volts for more than 0.6 seconds. |
| • | The PCM detects that the TP sensor 1 voltage is less than 0.2 volts for more than 0.4 seconds. |
| • | The PCM detects that the TP sensor 2 voltage is less than 1.75 volts for more than 0.4 seconds. |
Action Taken When the DTC Sets
| • | DTC P0120, P0121, P0122, P0123, P0220, P0222, P0223 and P2135 are Type A DTCs. |
| • | The engine operates in the Reduced Engine Power Mode with the TP sensor 1 angle defaulted to 19 percent. |
Conditions for Clearing the DTC
DTC P0120, P0121, P0122, P0123, P0220, P0222, P0223 and P2135 are Type A DTCs.
Diagnostic Aids
DTCs P0606 and P0607 indicate the 5-volt reference circuit was shorted to ground. The engine may not start and the PCM may not communicate with the scan tool during a shot to ground in the 5-volt reference circuit.
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Throttle Actuator Control (TAC) System Description
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Ignition ON, observe that the scan tool TP sensor 1 parameter is between 7-19 percent.
- Ignition ON, observe that the scan tool TP sensor 2 parameter is between 2.3-2.6 volts.
- Observe both scan tool TP sensor parameters while pressing the accelerator pedal from a closed throttle to wide open throttle (WOT). Both TP sensor parameters should change.
- Rapidly depress the accelerator pedal from the rest position to the WOT position and release pedal. Repeat the procedure several times. DTCs P0120, P0121, P0122, P0123, P0220, P0222, P0223, or P2135 should not set.
- Slowly depress the accelerator pedal to WOT and then slowly return the pedal to closed throttle. Repeat the procedure several times. DTCs P0120, P0121, P0122, P0123, P0220, P0222, P0223, or P2135 should not set.
- Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the throttle body assembly.
- Ignition OFF, test for 10 ohms or less between the low reference circuit terminal 3 and ground G104.
- Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 5 and ground.
- Test for 4.8-5.2 volts between the TP senosr signal circuit terminal listed below and ground.
- If all circuits test normal, test or replace the throttle body assembly.
| ⇒ | If greater than the specified range, test the low reference circuit for a short to voltage, or an open/high resistance. If the circuit tests normal, replace the PCM. |
| ⇒ | If less than the specified range, test the 5-volt reference circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the PCM. |
| ⇒ | If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the PCM. |
| • | TP sensor 1 terminal 6 |
| • | TP sensor 2 terminal 4 |
| ⇒ | If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the PCM. |
| ⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the PCM. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for control module replacement, setup, and programming |
