The throttle position (TP) sensors 1 and 2 are located within the throttle body assembly. Each sensor has the following components:
| • | A 5-volt reference circuit | 
| • | A low reference circuit | 
| • | A signal circuit | 
This provides the engine control module (ECM) with a signal voltage proportional to throttle plate movement. TP sensor 1 signal voltage at closed throttle is near the 5-volt reference and decreases as the throttle plate is opened. TP sensor 2 signal voltage at closed throttle is near the low reference and increases as the throttle plate is opened. If the ECM detects the TP sensor 2 signal voltage is not within the predicted range, DTC P0220 sets.
This diagnostic procedure supports the following DTC:
DTC P0220 Throttle Position (TP) Sensor 2 Circuit
| • | DTCs P0601, P0602, P0603, P0604, P0606, P0607, P0641, P0651 are not set. | 
| • | The ignition is ON, with the engine OFF, or the engine is operating. | 
| • | The ignition 1 voltage is more than 5.23 volts. | 
| • | DTC P0220 runs continuously when the above conditions are met. | 
| • | The ECM detects that the TP sensor 2 signal voltage is less than 0.35 volt for less than 1 second. | 
| • | The ECM detects that the TP sensor 2 signal voltage is more than 4.65 volts for less than 1 second. | 
| • | 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. | 
| • | 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. | 
Step  | Action  | Values  | Yes  | No  | 
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module Connector End Views or Engine Controls Connector End Views  | ||||
1  | Did you perform the Diagnostic System Check - Vehicle?  | --  | Go to Step 2  | |
2  | 
 Does the scan tool indicate voltage less than the first value or more than the second value?  | 0.35 V 4.65 V  | Go to Step 6  | Go to Step 3  | 
3  | Is DTC P2135 also set?  | --  | Go to Step 4  | |
4  | 
 Does DTC P0220 set by itself?  | --  | Go to Step 21  | Go to Step 5  | 
5  | Are there any other DTCs set?  | --  | Go to Testing for Intermittent Conditions and Poor Connections  | |
6  | 
 Does the scan tool indicate voltage at the specified value?  | 0 V  | Go to Step 7  | Go to Step 12  | 
7  | 
 Does the scan tool indicate the TP sensor 2 voltage at the specified value?  | 5 V  | Go to Step 8  | Go to Step 9  | 
8  | Probe the TP sensor low reference circuit with a test lamp connected to B+. Does the test lamp illuminate?  | --  | Go to Step 18  | Go to Step 14  | 
9  | Measure the voltage of the TP sensor 2 5-volt reference circuit with a DMM. Does the DMM indicate voltage at the specified value?  | 5 V  | Go to Step 11  | Go to Step 10  | 
10  | Does the DMM indicate voltage less than the specified value on the TP sensor 2 5-volt reference circuit?  | 5 V  | Go to Step 15  | Go to Step 17  | 
11  | Test the TP sensor 2 signal circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?  | --  | Go to Step 22  | Go to Step 13  | 
12  | Test the TP sensor 2 signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?  | --  | Go to Step 22  | Go to Step 20  | 
13  | Test the TP sensor 2 signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?  | --  | Go to Step 22  | Go to Step 20  | 
14  | Test the TP sensor 2 low reference circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?  | --  | Go to Step 22  | Go to Step 20  | 
15  | Test the TP sensor 2 5-volt reference circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?  | --  | Go to Step 22  | Go to Step 16  | 
16  | Test the TP sensor 2 5-volt reference circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?  | --  | Go to Step 22  | Go to Step 20  | 
17  | Test the TP sensor 2 5-volt reference circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?  | --  | Go to Step 22  | --  | 
18  | Test for an intermittent and for a poor connection at the throttle body. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?  | --  | Go to Step 22  | Go to Step 19  | 
19  | Replace the throttle body assembly. Refer to Throttle Body Assembly Replacement . Did you complete the replacement?  | --  | Go to Step 22  | --  | 
20  | Test for an intermittent and for a poor connection at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?  | --  | Go to Step 22  | Go to Step 21  | 
21  | Replace the ECM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement?  | --  | Go to Step 22  | --  | 
22  | 
 Did the DTC fail this ignition?  | --  | Go to Step 2  | Go to Step 23  | 
23  | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?  | --  | System OK  | |