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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1442 (Engine Control System - Diagnosis - 4.2L (DTC P0507 To DTC P2176)) >> Diagnosis Information & Procedures >> DTC P2138 >> Test Description

Test Description

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

  1. 2:  Any circuit faults on either APP sensor 1 or 2 will set one of the DTCs listed. Refer to the appropriate table for diagnosis.
DTC P2138

Step Action Values Yes No
Schematic Reference:  Engine Controls Schematics 
Connector End View Reference:  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  Observe the DTC information with a scan tool.
Is DTC P0120, P0220, P0641, P0651, P2120, or P2125 also set?		 - Go to Diagnostic Trouble Code (DTC) List Go to Step 3 
3
  1. Turn OFF the ignition.
  2. Disconnect the accelerator pedal position (APP) sensor electrical connector.
  3. Disconnect the powertrain control module (PCM).
  4. Use a DMM to measure the resistance of the following circuits for each of the APP sensors:
    • The low reference circuit
    • The signal circuit
    • The 5-volt reference circuit
Did any of the circuits measure more than the specified value?		 5ohm Go to Step 5  Go to Step 4 
4
  1. Test for a short between any of the circuits in the APP sensor harness.
  2. Repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 7  Go to Step 6 
5 Repair the high resistance in the circuit. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 - Go to Step 7  -
6 Replace the APP sensor. Refer to Accelerator Pedal Position (APP) Sensor Replacement .
Did you complete the replacement?		 - Go to Step 7  -
7
  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 8 
8 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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