Circuit Description
The PCM supplies a 5.0 volt reference signal and a ground to the sensor. The throttle position (TP) sensor sends a voltage signal back to the PCM relative to the throttle plate opening. The voltage will vary from approximately 0.35 volts at closed throttle, to over 4.65 volts at wide open throttle (WOT).
Conditions for Running the DTC
| • | No active MAP DTCs |
| • | Engine is running |
| • | MAP is less than 60 kPa |
| • | Engine speed is less than 1,500 RPM |
| Or |
| • | No active MAP DTCs |
| • | Engine is running |
| • | MAP is more than 60 kPa |
| • | Engine speed is more than 1,500 RPM |
Conditions for Setting the DTC
The TP sensor voltage is more than 3.9 volts for 13.75 seconds when the engine speed is less than 1,500 RPM.
Or
TP sensor voltage is more than 4.8 volts when the engine speed is more than 1500 RPM.
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) if a failure is detected during 2 consecutive key cycles. |
| • | The control module sets the DTC and records the operating conditions at the time the diagnostic failed. The failure information is stored in the scan tools Freeze Frame and Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the MIL after 3 consecutive drive trips when the test has Run and Passed |
| • | A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles. A warm up cycle occurs when the coolant temperature has risen 22°C (40°F) from the startup coolant temperature and the engine coolant reaches a temperature that is more than 70°C (158°F) during the same ignition cycle. |
| • | Use a scan tool to clear the DTCs. |
Diagnostic Aids
| • | With the ignition ON and the throttle at closed position, the voltage should read between 0.20 volts and 0.90 volts and increase steadily to over 4.5 volts at wide open throttle. |
| • | Check the connectors for proper mating. Replace as necessary. Repair as necessary. |
An intermittent may be caused by any of the following conditions:
| • | A poor connection |
| • | Rubbed through wire insulation |
| • | A broken wire inside the insulation |
Thoroughly inspect any circuitry that is suspected of causing the intermittent complaint. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
If a repair is necessary, refer to Wiring Repairs or Connector Repairs in Wiring Systems.
Test Description
The numbers below refers to the step numbers on the diagnostic table:
-
With the throttle closed, the TP sensor voltage should read less than 0.80 volts. If the TP sensor voltage does not read less than 0.80 volts, check for a binding or a sticking throttle cable.
-
The PCM and the wiring are OK if the TP sensor voltage is less than 0.3 volts with the TP sensor connector disconnected.
-
Probing the ground circuit with a test lamp tests the circuit for high resistance which will cause a DTC P0123 to set.
-
Important: The powertrain control module (PCM) uses a single internal 5.0 volt power supply to supply power to all the engine control components. If one component shorts its 5.0 volt reference circuit to ground or battery voltage, the other 5.0 volt reference circuits will also have a low or high voltage.
A shorted 5.0 volt reference circuit will also set additional DTCs.
-
The replacement PCM must be programmed and the Crankshaft Position System Variation Learn procedure must be performed.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
Does the TP sensor voltage read more than the specified value? | 0.8 V | |||
3 |
Does the TP sensor voltage read more than the specified value? | 3.9 V | ||
Does the TP sensor voltage read less than the specified value? | 0.3 V | |||
Does the test lamp illuminate? | -- | |||
6 |
Did you find and correct the condition? | -- | ||
|
Important: The powertrain control module (PCM) uses a single internal 5.0 volt power supply to supply power to all the engine control components. If one component shorts its 5.0 volt reference circuit to ground or battery voltage, the other 5.0 volt reference circuits will also have a low or high voltage.
Did you find and correct the condition? | -- | |||
8 |
Did you find and correct the condition? | -- | ||
9 |
Did you find and correct the condition? | -- | ||
10 | Replace the TP sensor. Refer to Throttle Position Sensor Replacement . Did you complete the replacement? | -- | -- | |
11 |
Did you find and correct the condition? | -- | ||
|
Important:: The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Did you complete the replacement? | -- | -- | ||
13 |
Does the DTC reset? | -- | System OK |
