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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 991 (Engine Controls Diagnosis - 6.6L (Lb7) (DTCS P0016 To P0236)) >> Diagnosis >> DTC P0102 >> Test Description

Test Description

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

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

  1. 11:  A short to another ECM-controlled circuit may not be present when the ECM is disconnected as part of the previous test. A short across two ECM circuits can cause this DTC to set.
DTC P0102

Step Action Values Yes No
Schematic Reference:  Engine Controls Schematics 
Connector End View Reference: Engine Control Module (ECM) 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
  1. Start the engine.
  2. Monitor the Diagnostic Trouble Code (DTC) information using the scan tool.
Does the scan tool display any other DTCs set?		 - Go to Diagnostic Trouble Code (DTC) List Go to Step 3 
3
  1. Observe the Freeze Frame/Failure Records for this DTC.
  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 4  Go to Diagnostic Aids
4 Inspect the fuse in the ignition 1 voltage circuit of the mass air flow (MAF) sensor.
Is the fuse open?		 - Go to Step 9  Go to Step 5 
5
  1. Turn OFF the ignition.
  2. Inspect for air leaks in the following components:
    • A damaged MAF sensor housing
    • The air induction system and the turbocharger system
    • The MAF sensor O-ring seal
    • The boost pressure sensor seal
  3. Inspect for the following conditions:
    • An obstructed intake air duct or a dirty air filter element
    • Any debris that is blocking the air sensing filaments of the MAF sensor
    • A MAF sensor that is installed backwards
    • A restricted exhaust system-Refer to Restricted Exhaust in Engine Exhaust.
Did you find and correct the condition?		 - Go to Step 20  Go to Step 6 
6
  1. Start the engine and allow the engine to idle.
  2. Observe the MAF Sensor parameter with a scan tool.
  3. Move the harness and the connector of the MAF sensor.
Does the movement of the harness or the connector affect the MAF Sensor parameter?		 - Go to Step 15  Go to Step 7 
7
  1. Turn OFF the engine.
  2. Turn ON the ignition, with the engine OFF.
  3. Disconnect the harness connector of the MAF sensor.
  4. Connect a test lamp between the ignition 1 voltage circuit of the MAF sensor and a good ground. Refer to Circuit Testing in Wiring Systems.
Does the test lamp illuminate?		 - Go to Step 8  Go to Step 13 
8
  1. Connect a 3-amp fused jumper wire between the signal circuit of the intake air temperature (IAT) sensor and the signal circuit of the MAF sensor. Refer to Circuit Testing in Wiring Systems.
  2. Observe the MAF Sensor parameter with a scan tool.
Did the MAF Sensor parameter change to the specified value?		 445 g/s Go to Step 16  Go to Step 10 
9 Test for continuity between the ignition 1 voltage circuit of the MAF sensor and ground with a DMM. Refer to Circuit Testing in Wiring Systems.
Does the DMM indicate continuity?		 - Go to Step 12  Go to Step 16 
10
  1. Turn OFF the ignition.
  2. Disconnect the fused jumper wire.
  3. Disconnect the engine control module (ECM).
  4. Test the signal circuit between the ECM and the MAF sensor for the following conditions:
    • A high resistance or an open
    • A short to ground
    • A short to the low reference circuit of the MAF sensor or IAT sensor-Refer to Circuit Testing in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 20  Go to Step 11 
11  Test for continuity at the harness connector of the ECM from the signal circuit of the MAF sensor to all other circuits at both ECM connectors with a DMM. Refer to Circuit Testing in Wiring Systems.
Does the DMM indicate continuity between any other circuit?		 - Go to Step 14  Go to Step 17 
12
  1. Repair the short to ground in the ignition 1 voltage circuit of the MAF sensor. Refer to Wiring Repairs in Wiring Systems.
  2. Replace the fuse as needed.
Did you complete the repair?		 - Go to Step 20  -
13 Repair the open in the ignition 1 voltage circuit of the MAF sensor. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 - Go to Step 20  -
14 Repair the circuits that are shorted together. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 - Go to Step 20  -
15 Repair the harness or the connections as necessary. Refer to Connector Repairs in Wiring Systems.
Did you complete the repair?		 - Go to Step 20  -
16 Inspect for poor connections at the harness connector of the MAF sensor. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 20  Go to Step 18 
17 Inspect for poor connections at the harness connector of the ECM. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 20  Go to Step 19 
18 Replace the MAF/IAT sensor. Refer to Mass Air Flow (MAF)/Intake Air Temperature (IAT) Sensor Replacement .
Did you complete the replacement?		 - Go to Step 20  -
19 Replace the ECM. Refer to Engine Control Module (ECM) Replacement .
Did you complete the replacement?		 - Go to Step 20  -
20
  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 21 
21 With a scan tool observe the stored information, Capture Info.
Does the scan tool display any DTCs that you have not diagnosed?		 - Go to Diagnostic Trouble Code (DTC) List System OK
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