Circuit Description
The Throttle Position (TP) sensor is a potentiometer. The gasoline Control Module (VCM / PCM or ECM) supplies about 5 volts on the TP sensor reference voltage circuit. The gasoline Control Module also supplies a ground circuit to the TP sensor. When the throttle is depressed the TP signal voltage rises to near the supplied 5 volts. As the throttle is released the TP signal voltage drops to around 0.6 volts. The gasoline Control Module and the AF ECU monitor the TP signal circuit voltage and determine the angle (or opening) of the throttle blade.
This DTC is used to indicate a throttle angle that is greater than calculated, based upon engine speed and engine MAP.
Conditions for Running the DTC
| • | The engine is operating on alternative fuel. |
| • | The engine has been operating for greater than 2 seconds. |
| • | No AF ECU DTC's are set. DTC's P1215, P1432 and P1433 may be set. |
| • | Engine MAP is less than 55 kPa. |
| • | TP sensor angle has changed less than 2 percent for 2 seconds continuously. |
Conditions for Setting the DTC
The AF ECU monitors a throttle angle that is greater than calculated, based upon engine speed and engine MAP.
Action Taken When the DTC Sets
| • | A first failure of this DTC will NOT illuminate the MIL and will store as Last Test Failed but not as History. |
| • | The AF ECU will illuminate the MIL and store the DTC as History after TWO consecutive drive trips that the diagnostic runs and fails. |
| • | The AF ECU will record operating conditions at the time the DTC sets. This information will be stored as Freeze Frame data. |
Conditions for Clearing the MIL/DTC
| • | The Last Test Failed status will clear when the DTC runs and passes. |
| • | The AF ECU will turn OFF the MIL after 3 consecutive drive trips that the DTC runs and passes. |
| • | The History status will clear after 40 consecutive WARM-UP cycles with NO failures of ANY DTC. |
| • | All DTC Information can be cleared using a scan tool. |
| • | Interruption of Control Module (AF ECU / VCM / PCM or ECM) power or ground MAY clear DTC Information. Clearing DTC Information with this method is inconsistent and should not be performed. |
Diagnostic Aids
Fault Not Present
Fault Not Present indicates the condition that caused the DTC to set is intermittent and not currently present. Refer to Intermittent Conditions Symptom diagnosis for additional information. If any additional DTCs were stored proceed to the applicable DTC table in the order stated in the OBD System Check.
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
-
This step indicates this sensor is currently functioning correctly. If you were sent to this diagnostic procedure from other service information return to that procedure now.
-
This step isolates the Signal circuit from the other possible causes of the DTC condition.
-
This step determines if the 5 Volt Reference circuit has the proper voltage. The current available on the 5 Volt Reference circuit should be about 180 mA.
-
This step determines if the Signal circuit is shorted to voltage or open.
-
This step determines if the Sensor Ground circuit has good continuity. With the TP Signal circuit (jumpered to 5 volts) grounded through the Sensor Ground circuit terminal, very little voltage should be available at the TP Signal circuit.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the AF Powertrain On-Board Diagnostic (OBD) System Check? | -- | Go to Alternative Fuels (AF) Powertrain On Board (OBD) System Check | |
2 |
Does the scan tool display the throttle angle below the specified value? | 2% | ||
3 | Depress the throttle slowly to wide open throttle (WOT). Does the scan tool display the throttle angle ABOVE the specified value? | 98% | ||
4 | Release the throttle. Does the scan tool display the throttle angle BELOW the specified value? | 2% | ||
The fault is not present. Refer to Diagnostic Aids. Are any DTC's stored that have not been diagnosed? | -- | Go to the Diagnostic Trouble Code (DTC) List | Go to Intermittent Conditions | |
Other DTC's may set. Does the scan tool display the TP Sensor voltage greater than the specified value? | 4.9 V | |||
Is the voltage WITHIN the specified value range? | 4.8 - 5.2 V | |||
If the jumper fuse opens, repair the Signal circuit shorted to battery voltage. Other DTC's may set. Does the scan tool display TP Sensor voltage LESS than the specified value? | 0.08 V | |||
Other DTC's may set. Does the scan tool display TP Sensor voltage LESS than the specified value? | 0.08 V | |||
10 |
Was a wiring repair made? | -- | ||
11 |
Was a wiring repair made? | -- | ||
12 |
Is the voltage WITHIN the specified value range? | 4.8 - 5.2 V | ||
13 |
Was a wiring repair made? | -- | ||
14 |
Was a repair necessary? | -- | ||
15 |
Was a repair made? | -- | ||
16 | Replace the TP Sensor. Refer to Throttle Position Sensor Replacement in the Engine Controls section of the gasoline service manual. Is the replacement complete? | -- | -- | |
17 |
Important: The following control module replacement procedures must all be completed before attempting to operate the vehicle.
Important: In order to perform the variation learn procedure a switch-over to gasoline operation is necessary. Remove the CNG 20 amp fuse in order to perform the switch-over. All of the above procedures are located in the gasoline service manual. Is the replacement complete? | -- | -- | |
18 |
Is the replacement complete? | -- | -- | |
19 |
Did this DTC RUN and PASS? | -- | System OK |
