LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2007 >> Chevy Express G2500, Van Cargo, 6.6 6 >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 16 (Engine Control System & Fuel System - 4.8L, 5.3L, And 6.0L - DTC P0452 To DTC P2135) >> DTC P2120 >> Test Description

Test Description

WARNING: This page is about a different variant/trim than selected.

The number below refers to the step number on the diagnostic table.

  1. 23:  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. Remember this if you review the stored information in Capture Info.
DTC P2120

Step Action Values Yes No
Schematic Reference:  Engine Controls Schematics 
Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module Connector End Views
1 Did you perform the Diagnostic System Check - Vehicle? - Go to Step 2  Go to Diagnostic System Check - Vehicle
2
IMPORTANT: If DTCs P0120 or U0107 is also set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .
  1. Turn ON the ignition with the engine OFF, and with your foot OFF the accelerator pedal.
  2. Observe the accelerator pedal position (APP) sensor 1 voltage with a scan tool.
Does the scan tool indicate the APP sensor 1 voltage is within the specified values?		 0.24-2.24 V Go to Step 3  Go to Step 6 
3 Depress the accelerator pedal to the wide open throttle (WOT) position.
Does the scan tool indicate APP sensor 1 voltage within the specified values?		 0.24-4.49 V Go to Step 4  Go to Step 6 
4
  1. Turn OFF the ignition for 30 seconds.
  2. Turn ON the ignition, with the engine OFF.
  3. Select the DTC option using the scan tool.
  4. Lightly touch and move the related engine wiring harnesses and connectors while monitoring the DTC information.
Did this DTC fail this ignition during the above test?		 - Go to Testing for Intermittent Conditions and Poor Connections Go to Step 5 
5
  1. Continue to observe the DTC information.
  2. Depress the accelerator pedal to WOT, then return the pedal to the rest position.
Did this DTC fail this ignition during the above test?		 - Go to Step 19  Go to Diagnostic Aids
6
  1. Turn OFF the ignition.
  2. Disconnect the accelerator pedal harness connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Observe the accelerator pedal position (APP) sensor 1 voltage parameter with a scan tool.
Does the scan tool indicate voltage at the specified value?		 0 V Go to Step 7  Go to Step 12 
7
  1. Connect a fused jumper wire between the APP sensor 1 5-volt reference circuit and the APP sensor 1 signal circuit at the accelerator pedal harness connector.
  2. Observe the APP sensor 1 voltage parameter with a scan tool.
Does the scan tool indicate the APP sensor 1 voltage at the specified value?		 5 V Go to Step 8  Go to Step 9 
8 Probe the APP 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 APP sensor 1 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 APP sensor 1 5-volt reference circuit? 5 V Go to Step 15  Go to Step 17 
11 Test the APP sensor 1 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 APP sensor 1 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 APP sensor 1 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 APP sensor 1 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 APP sensor 1 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 APP sensor 1 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 APP sensor 1 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 Inspect for poor connections at the harness connector of the accelerator pedal harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals .
Did you find and correct the condition?		 - Go to Step 22  Go to Step 19 
19 Replace the accelerated pedal assembly. Refer to Accelerator Pedal Position Sensor Replacement .
Did you complete the replacement?		 - Go to Step 22  -
20 Inspect for poor connections at the harness connector of the throttle actuator control (TAC) module. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals .
Did you find and correct the condition?		 - Go to Step 22  Go to Step 21 
21 Replace the TAC module. Refer to Electronic Throttle Actuator Control Module Replacement .
Did you complete the replacement?		 - Go to Step 22  -
22
  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.
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?		 - Go to Diagnostic Trouble Code (DTC) List - Vehicle System OK
scientia non olet · About LEMON Manuals