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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1568 (Engine Controls Diagnostic (DTC P0172 To DTC P0455) -- 5.7L) >> Diagnosis >> DTC P0220 >> Test Description

Test Description

WARNING: This page is about a different car, the 2004 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers on the diagnostic table.

  1. 12:  Using a test lamp reduces the amount of current fed into the signal circuit. The scan tool should display the maximum value for this parameter, 5-volts even though the actual voltage is higher.
  2. 18:  The TP 2 sensor and the APP 2 sensor share a common 5 volt reference. The 5-volt reference circuits are connected internally within the TAC module. Disconnecting the TAC module will isolate the 5-volt reference circuits.
  3. 19:  The TP sensor 2 and the APP sensor 2 share a common 5-volt reference. A short to voltage on the APP sensor 2 5-volt reference circuit will affect the TP sensor 2 5-volt reference circuit.
  4. 36:  When the TAC module detects a condition within the TAC system, more than 1 TAC system related DTC may set. This condition is due to the many redundant tests that run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting components during testing may set additional DTCs. Keep this in mind when reviewing the Capture Info.
DTC P0220

Step Action Values Yes No
Schematic Reference:  Engine Controls Schematics 
Connector End View References:  Powertrain Control Module (PCM) Connector End Views  or  Engine Controls Connector End Views 
1 Did you perform the Diagnostic System Check-Engine Controls? - Go to Step 2  Go to Diagnostic System Check - Engine Controls
2 Is DTC P1515, P1516, or P1518 also set? - Go to Diagnostic Trouble Code (DTC) List Go to Step 3 
3
  1. Turn OFF the ignition.
  2. Remove the air inlet duct from the throttle body assembly.
  3. Disconnect the throttle actuator motor harness connector.
  4. Turn ON the ignition, with the engine OFF.
  5. Manually close the throttle blade completely while observing the throttle position (TP) sensor 2 voltage parameter on the scan tool.
Does the scan tool indicate that the TP sensor 2 voltage is within the specified values?		 4.3-4.8 V Go to Step 4  Go to Step 7 
4 Open the throttle blade to wide open throttle (WOT) by hand while observing the TP sensor 2 voltage parameter on the scan tool.
Does the scan tool indicate TP sensor 2 voltage within the specified values?		 0.13-1 V Go to Step 5  Go to Step 7 
5
  1. Turn OFF the ignition for 15 seconds.
  2. Reconnect the throttle actuator motor harness connector.
  3. Reinstall the air inlet duct.
  4. Turn ON the ignition with the engine OFF.
  5. Select the DTC Info. Option on the scan tool.
  6. Lightly touch and move the related engine wiring harnesses and connectors for the throttle position (TP) sensor while observing the DTC Info. The DTC will set if an intermittent condition is present. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 35  Go to Step 6 
6
  1. Continue to observe DTC Info.
  2. Slowly depress the accelerator pedal to WOT and then slowly return the pedal to the released position 3 times.
Does the scan tool indicate this DTC failed this ignition?		 - Go to Step 26  Go to Diagnostic Aids
7 Observe the TP sensor 2 voltage parameter, with a scan tool.
Does the scan tool indicate that the TP sensor 2 voltage is at the specified value?		 5 V Go to Step 8  Go to Step 12 
8 Disconnect the TP sensor harness connector.
Does the scan tool indicate that the TP sensor 2 voltage is at the specified value?		 0 V Go to Step 9  Go to Step 13 
9
  1. Disconnect the accelerator pedal position (APP) sensor harness connector.
  2. Turn ON the ignition with the engine OFF.
  3. Test the TP sensor 2 5-volt reference circuit for voltage, with a DMM.
Does the DMM indicate voltage near the specified value?		 5 V Go to Step 10  Go to Step 18 
10 With a DMM connected between the TP sensor 1 low reference circuit and the TP sensor 2 low reference circuit at the TP sensor harness connector, test for resistance
Does the DMM indicate resistance within the specified values?		 0-5 Ω Go to Step 14  Go to Step 11 
11
  1. Turn OFF the ignition.
  2. Disconnect the throttle actuator control (TAC) module harness connector containing the TP sensor circuits.
  3. Test the TP sensor 2 low reference circuit for an open or for high resistance, with a DMM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 35  Go to Step 32 
12 
  1. Disconnect the TP sensor harness connector.
  2. Connect a test lamp between the TP sensor 2 signal circuit and the battery positive voltage.
Does the scan tool indicate TP sensor 2 voltage near the specified value?		 5 V Go to Step 20  Go to Step 15 
13
  1. Turn OFF the ignition.
  2. Disconnect the TAC module harness connector containing the TP sensor circuits.
  3. Turn ON the ignition.
  4. Test the TP sensor 2 signal circuit for a short to voltage, with a DMM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 35  Go to Step 17 
14
  1. Turn OFF the ignition.
  2. Disconnect the TAC module harness connector containing the APP sensor circuits.
  3. Turn ON the ignition with the engine OFF.
  4. Test the APP sensor 2 signal circuit for a short to voltage, with a DMM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 35  Go to Step 24 
15
  1. Turn OFF the ignition.
  2. Disconnect the TAC module harness connector containing the TP sensor circuits.
  3. Test the TP sensor 2 signal circuit for an open or for high resistance, with a DMM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 35  Go to Step 16 
16 Test the TP sensor 2 signal circuit for a short to ground, with a DMM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 35  Go to Step 17 
17 Test for a short between the TP sensor 2 signal circuit and all other TAC module circuits, with a DMM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 35  Go to Step 32 
18 
  1. Turn OFF the ignition.
  2. Disconnect the TAC module harness connector containing the TP sensor circuits.
  3. Turn ON the ignition with the engine OFF.
  4. Test the TP sensor 2 5-volt reference circuit for a short to voltage, with a DMM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 35  Go to Step 19 
19 
  1. Turn OFF the ignition.
  2. Disconnect the other TAC module harness connector.
  3. Turn ON the ignition with the engine OFF.
  4. Test the APP sensor 2 5-volt reference circuit for a short to voltage, with a DMM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 35  Go to Step 24 
20
  1. Turn OFF the ignition.
  2. Disconnect the TAC module harness connector containing the TP sensor circuits.
  3. Test the TP sensor 2 5-volt reference circuit for an open or for high resistance, with a DMM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 35  Go to Step 21 
21 Test the TP sensor 2 5-volt reference circuit for a short to ground, with a DMM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 35  Go to Step 22 
22
  1. Disconnect the APP sensor harness connector.
  2. Disconnect the other TAC module harness connector.
  3. Turn ON the ignition with the engine OFF.
  4. Test the APP sensor 2 signal circuit for a short to voltage, with a DMM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 35  Go to Step 23 
23 Test the APP sensor 2 5-volt reference circuit for a short to ground, with a DMM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 35  Go to Step 24 
24 Test the TP sensor 2 5-volt reference circuit for a short to voltage, with a DMM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 35  Go to Step 25 
25 Test for a short between the TP sensor 2 5-volt reference circuit and all other TAC module circuits, with a DMM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 35  Go to Step 26 
26 Test for a short between the APP sensor 2 5-volt reference circuit and all other TAC module circuits, with a DMM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 35  Go to Step 27 
27 Test the TP sensor 2 signal circuit for high resistance, with a DMM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 35  Go to Step 28 
28 Test the TP sensor 2 low reference circuit for resistance, with a DMM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 35  Go to Step 29 
29
  1. Reconnect the TAC module connectors.
  2. Turn ON the ignition.
  3. Measure the voltage at the TP sensor 2 5-volt reference circuit, with a DMM.
Does the DMM indicate voltage greater than the specified value?		 6.06 V Go to Step 32  Go to Step 30 
30
  1. Turn OFF the ignition.
  2. Connect a test lamp between APP sensor 2 5-volt reference and battery positive voltage.
Does the test lamp illuminate?		 - Go to Step 32  Go to Step 31 
31 Inspect for poor connections at the TP sensor harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 35  Go to Step 33 
32 Inspect for poor connections at the TAC module harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 35  Go to Step 34 
33
IMPORTANT: The TP sensor is not a serviceable part and should only be replaced with the throttle body assembly.
Replace the throttle body assembly. Refer to Throttle Body Assembly Replacement .Did you complete the replacement?		 - Go to Step 35  -
34 Replace the TAC module. Refer to Throttle Actuator Control (TAC) Module Replacement .
Did you complete the replacement?		 - Go to Step 35  -
35
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze/Frame Failure Records.
Does the DTC run and pass?		 - Go to Step 36  Go to Step 2 
36  Observe the Capture Info with a scan tool.
Are there any DTCs that have not been diagnosed?		 - Go to Diagnostic Trouble Code (DTC) List System OK
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