Circuit Description
The throttle position (TP) sensor is mounted on the throttle body assembly. The sensor is actually 2 individual TP sensors within one housing. Two separate signal, low reference and 5-volt reference circuits are used to connect the TP sensor assembly to the throttle actuator control (TAC) module. The 2 sensors have opposite functionality. The TP sensor 1 signal voltage is pulled up to reference voltage as the throttle opens, from below 1 volt at closed throttle to above 3.5 volts at wide open throttle (WOT). The TP sensor 2 signal voltage is pulled down to low reference from around 3.8 volts at closed throttle to below 1 volt at WOT. TP sensor 1 and APP sensor 1 share a 5-volt reference circuit that are connected within the TAC module. TP sensor 2 and APP sensor 2 share a 5-volt reference circuit that are connected within the TAC module. If an out of range condition is detected with the TP sensor 1, this diagnostic trouble code (DTC) will set and the Reduced Engine Power message will be displayed.
Conditions for Running the DTC
| • | DTCs P1517 and P1518 are not set. |
| • | The ignition switch is in the crank or run position. |
| • | The ignition voltage greater than 5.23 volts. |
Conditions for Setting the DTC
| • | TP sensor 1 signal voltage is less than 0.13 volts or greater than 4.87 volts. |
| • | All of the above conditions are present for less than 1 second. |
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. |
Diagnostic Aids
| • | Inspect the TAC module connectors for signs of water intrusion. When this occurs, multiple DTCs could be set with no circuit or component conditions found during diagnostic testing. |
| • | When the TAC module detects a condition within the TAC system, more than one TAC system related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing one individual condition may correct more than one DTC. Disconnecting components during testing may set additional DTCs. Keep this in mind when reviewing the stored information, Capture Info. |
| • | If this DTC is determined to be intermittent, refer to Intermittent Conditions . |
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic References: Engine Controls Schematics | ||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |
2 | Is DTC P1515, P1516, or P1518 also set? | -- | Go to Step 3 | |
3 |
Does the scan tool indicate TP sensor 1 voltage within the specified values? | 0.13-0.67 V | Go to Step 4 | Go to Step 8 |
4 | Open the throttle blade to wide open throttle (WOT) by hand while observing the TP sensor 1 voltage parameter on the scan tool. Does the scan tool indicate TP sensor 1 voltage within the specified values? | 4.09-4.87 V | Go to Step 5 | Go to Step 8 |
5 |
Did you find and correct the condition? | -- | Go to Step 31 | Go to Step 6 |
6 |
Did you find and correct the condition? | -- | Go to Step 31 | Go to Step 7 |
7 |
Does the scan tool indicate this DTC failed this ignition? | -- | Go to Step 26 | Go to Diagnostic Aids |
8 |
Does the DMM indicate voltage within the specified values? | 3.94-6.06 V | Go to Step 13 | Go to Step 9 |
9 |
Did you find and correct the condition? | -- | Go to Step 31 | Go to Step 10 |
10 | Use a DMM in order to test the TP sensor 1 signal circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 31 | Go to Step 11 |
11 | Use a DMM in order to test the TP sensor 1 signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 31 | Go to Step 12 |
12 |
Did you find and correct the condition? | -- | Go to Step 31 | Go to Step 27 |
13 | Use a DMM in order to test the TP sensor 1, 5-volt reference circuit for voltage. Does the DMM indicate voltage within the specified values? | 3.94-6.06 V | Go to Step 23 | Go to Step 14 |
14 | Does the DMM indicate voltage greater than the specified value? | 6.06 V | Go to Step 15 | Go to Step 17 |
15 |
Did you find and correct the condition? | -- | Go to Step 31 | Go to Step 16 |
16 |
Did you find and correct the condition? | -- | Go to Step 31 | Go to Step 21 |
17 | Disconnect the APP sensor. Does the DMM indicate voltage less than the specified value? | 3.94 V | Go to Step 18 | Go to Step 29 |
18 |
Did you find and correct the condition? | -- | Go to Step 31 | Go to Step 19 |
19 | Use a DMM in order to test the TP sensor 1, 5-volt reference circuit for a short to ground. Did you find and correct the condition? | -- | Go to Step 31 | Go to Step 20 |
20 | Use a DMM in order to test the APP sensor 1, 5-volt reference circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 31 | Go to Step 21 |
21 | Use a DMM in order to test for a short between the TP sensor 1, 5-volt reference circuit and all other TAC module circuits. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 31 | Go to Step 22 |
22 | Use a DMM in order to test for a short between the APP sensor 1, 5-volt reference circuit and all other TAC module circuits. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 31 | Go to Step 27 |
23 |
Does the scan tool indicate voltage near the specified value? | 0 V | Go to Step 25 | Go to Step 24 |
24 |
Did you find and correct the condition? | -- | Go to Step 31 | Go to Step 27 |
25 | Inspect for poor connections at the TP sensor harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 31 | Go to Step 28 |
26 | Inspect for poor connections at the APP module harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 31 | Go to Step 29 |
27 | Inspect for a poor connection at the TAC module harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 31 | Go to Step 30 |
28 |
Important: The throttle body and the throttle position sensor assembly should be replaced as a unit. Driveability concerns may result if either is replaced individually. Replace the throttle body assembly. Refer to Throttle Body Assembly Replacement . Did you complete the replacement? | -- | Go to Step 31 | -- |
29 | Replace the APP sensor. Refer to Accelerator Pedal Position Sensor Replacement . Did you complete the replacement? | -- | Go to Step 31 | -- |
30 | Replace the TAC module. Refer to Electronic Throttle Actuator Control Module Replacement . Did you complete the replacement? | -- | Go to Step 31 | -- |
31 |
Does the DTC run and pass? | -- | Go to Step 32 | Go to Step 2 |
With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | ||
