Refer to the
Cell 20: TP and APP Sensors
full page wiring schematic.
Circuit Description
The Throttle Position (TP) sensor is mounted on the throttle body assembly. The sensor is actually two individual Throttle Position sensors within one housing. Two separate signal, ground and 5.0 volt reference circuits are used to connect the TP sensor assembly and the Throttle Actuator Control (TAC) Module. The two sensors have opposite functionality. The TP sensor 1 signal voltage increases as the throttle opens, from below 1.1 volts at 0% throttle to above 3.7 volts at 100% throttle. The TP sensor 2 signal voltage decreases from above 3.9 volts at 0% throttle to below 1.2 volts at 100% throttle. Observe also that the signal circuit for TP Sensor 1 is pulled up to 5.0 volts and that the signal circuit for TP Sensor 2 is pulled to ground within the TAC Module.
Conditions for Running the DTC
| • | DTCs P0606, P1517, P1518 not set. |
| • | Ignition switch in the crank or run position. |
| • | Ignition voltage greater than 5.23 volts. |
Conditions for Setting the DTC
| • | TP sensor #1 voltage is less than 0.13 volts or greater than 4.87 volts. |
| • | All above conditions met for less than 1 second. |
Action Taken When the DTC Sets
| • | The PCM will illuminate the Malfunction Indicator Light (MIL) when this diagnostic runs and fails. |
| • | The Reduced Engine Power message displays on the drivers information center. |
| • | The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Freeze Frame and/or Failure Records. |
| • | If no other TAC System DTCs are set, the TAC System will operate in Reduced Engine Power mode. If certain TAC System DTCs are set at the same time, the TAC System either defaults to a more tightly restricted mode of operation if the TAC determines that limited safe operation is possible, or the TAC commands the engine to shut down. |
Conditions for Clearing the MIL/DTC
| • | The PCM turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A last test failed, or current DTC, clears when the diagnostic runs and does not fail. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Use a scan tool in order to clear the MIL and the DTC. |
Diagnostic Aids
Important: Remove any debris from the PCM\TAC module connector surfaces before servicing the PCM\TAC module. Inspect the PCM\TAC module connector gaskets when diagnosing/replacing the modules. Ensure that the gaskets are installed correctly. The gaskets prevent water intrusion into the PCM\TAC modules.
| • | The following may cause an intermittent: |
| - | Poor connections. Check for adequate terminal tension. Refer to Body and Accessories/Wiring Systems for proper procedure. |
| - | Corrosion |
| - | Mis-routed harness. |
| - | Rubbed through wire insulation. |
| - | Broken wire inside the insulation. |
| - | Inspect the TAC module connectors for signs of water intrusion. When this occurs, multiple DTCs should be set and no circuit or component problems can be located. |
| • | For an intermittent, refer to Symptoms . |
| • | If a repair is completed and the DTC was cleared using a scan tool on the same ignition cycle, the default action will not clear until an ignition cycle has occurred. |
| • | When the TAC module detects a problem 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 problem may correct more than one DTC. Keep this in mind when reviewing captured DTC info. |
Test Description
The numbers below refer to the step numbers on the Diagnostic Table.
-
Disconnect the Throttle Actuator connector before inserting fingers into the throttle bore. After you complete this step, install the air inlet duct to the throttle body.
-
The TP 1 sensor and the APP 1 sensor share a common 5.0 volt reference. The 5.0 volt reference circuits are connected internally within the TAC module. Disconnecting the TAC module will isolate the 5.0 volt reference circuits.
-
The TP 1 sensor and the APP 1 sensor share a common 5.0 volt reference. The 5.0 volt reference circuits are connected internally within the TAC module. Disconnecting the TAC module will isolate the 5.0 volt reference circuits.
-
The APP sensor 1 and the TP sensor 1 share a command 5.0 volt reference circuit. This step checks the APP sensor 1 for a short to B+.
-
This test determines whether or not the TAC Module can recognize a change in signal voltage.
-
There are three separate 5.0 volt reference sources within the TAC Module. The TP sensor 1 and the APP sensor 1 share one 5.0 volt reference source. The TP sensor 2 and the APP sensor 2 share another common 5.0 volt reference source and the APP sensor 3 uses the third circuit alone. This test determines whether the signal circuit is shorted to any one of the 5.0 volt reference circuits. If a short exists, the corresponding APP sensor voltage will be pulled low.
-
The previous step found the signal circuit and a 5.0 volt reference circuit shorted together. This test isolates whether the short is in the harness or within the TAC Module.
-
When the TAC module detects a problem 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 problem may correct more than one DTC. Keep this in mind when reviewing the captured DTC information.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | Go to (Link no longer avaliable) | |
2 | Is DTC P1515 or P1516 also set? | -- | Diagnose these DTCs first | |
|
Important: If DTC P1518 is also set, refer to DTC P1518 for further diagnosis.
Important: Disconnecting the throttle actuator motor connector causes additional DTCs to set. Is the voltage within the specified range? | 0.13-0.67V | |||
4 | Open the throttle blade to Wide Open Throttle (WOT) by hand while observing the TP sensor 1 voltage on the scan tool. Is the voltage within the specified range? | 4.09-4.87V | ||
5 |
Does the harness movement cause this DTC to set? | -- | ||
6 |
Did this DTC set? | -- | Go to Diagnostic Aids | |
7 |
Is the voltage within the specified range? | 3.94-6.06V | ||
8 |
Is any voltage present? | -- | ||
9 | Check the harness for continuity of the TP sensor 1 signal circuit using the DMM (Link no longer avaliable) . Does the DMM indicate continuity? | -- | ||
10 | Check the harness for continuity between the TP sensor 1 signal circuit and the battery ground using the DMM (Link no longer avaliable) . Does the DMM indicate continuity? | -- | ||
11 | Check the harness for continuity between the TP sensor 1 signal circuit, at the TAC harness connector, and all other circuits in both TAC module connectors using the DMM (Link no longer avaliable) . Does the DMM indicate continuity? | -- | ||
12 | Measure the voltage from the TP sensor 1 5.0 volt reference circuit in the TP sensor harness connector to the battery ground using the DMM (Link no longer avaliable) . Is the voltage within the specified range? | 3.94-6.06V | ||
13 |
Is any voltage present? | -- | ||
Is any voltage present? | -- | |||
15 | Check the harness for continuity of the TP sensor 1 5.0 volt reference circuit using the DMM (Link no longer avaliable) . Does the DMM indicate continuity? | -- | ||
16 | Check the harness for continuity between the TP sensor 1 5.0 volt reference circuit and the battery ground using the DMM (Link no longer avaliable) . Does the DMM indicate continuity? | -- | ||
17 | Check the harness for continuity between the APP sensor 1 5.0 volt reference circuit and the battery ground using the DMM (Link no longer avaliable) . Does the DMM indicate continuity? | -- | ||
18 | Check the harness for continuity between the TP sensor 1 5.0 volt reference circuit, at the TAC harness connector, and all other circuits in both TAC module connectors using the DMM (Link no longer avaliable) . Does the DMM indicate continuity? | -- | ||
19 | Check the harness for continuity between the APP sensor 1 5.0 volt reference circuit, at the TAC harness connector, and all other circuits in both TAC module connectors using the DMM (Link no longer avaliable) . Does the DMM indicate continuity? | -- | ||
20 | Measure the resistance from the TP sensor 1 ground circuit in the TP sensor harness connector to the battery ground using the DMM (Link no longer avaliable) . Is the resistance within the specified range? | 0-5ohms | ||
21 |
Does the DMM indicate continuity? | -- | ||
Does the scan tool indicate the specified voltage? | 0V | |||
Are any of the APP sensor voltages affected when the TP sensor 1 signal circuit is grounded? | -- | |||
Does the DMM indicate continuity? | -- | |||
25 | Repair the harness/connections as necessary. Refer to Body and Accessories/Wiring Systems. Is the action complete? | -- | -- | |
26 | Repair the short to voltage in the 5.0 volt reference circuit. Refer to Body and Accessories/Wiring Systems. Is the action complete? | -- | -- | |
27 | Repair the open/high resistance in the 5.0 volt reference circuit. Refer to Body and Accessories/Wiring Systems. Is the action complete? | -- | -- | |
28 | Repair the short to a ground in the 5.0 volt reference circuit. Refer to Body and Accessories/Wiring Systems. Is the action complete? | -- | -- | |
29 | Repair the signal circuit for a shorted to voltage. Refer to Body and Accessories/Wiring Systems. Is the action complete? | -- | -- | |
30 | Repair the open/high resistance in the signal circuit. Refer to Body and Accessories/Wiring Systems. Is the action complete? | -- | -- | |
31 | Repair the short to a ground in the signal circuit. Refer to Body and Accessories/Wiring Systems. Is the action complete? | -- | -- | |
32 | Repair the open/high resistance in the ground circuit. Refer to Body and Accessories/Wiring Systems. Is the action complete? | -- | -- | |
33 | Repair the circuits that are shorted together. Refer to Body and Accessories/Wiring Systems. Is the action complete? | -- | -- | |
34 | Check for a poor connection/terminal tension at the TP sensor harness connector. Refer to Body and Accessories/Wiring Systems for proper procedure. Did you find and correct the condition? | -- | ||
35 | Replace the throttle body assembly. Is the action complete? | -- | -- | |
36 | Check for a poor connection/terminal tension at the TAC Module harness connector. Refer to Body and Accessories/Wiring Systems for proper procedure. Did you find and correct the condition? | -- | ||
37 | Replace the TAC Module. Refer to (Link no longer avaliable) . Is the action complete? | -- | -- | |
38 |
Does the scan tool indicate that this diagnostic ran and passed? | -- | ||
Select the Capture Info option and the Review Info option using the scan tool. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to the applicable DTC table | System OK |
