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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1382 (Engine Control System Diagnosis (DTC P0010 To DTC P0128) -- 1.8L (LNK)) >> Diagnosis >> DTC P0100 >> Test Description

Test Description

WARNING: This page is about a different car, the 2004 Pontiac Vibe. 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. 1:  The Diagnostic System Check-Engine Controls prompts the technician to complete some basic checks and store the Freeze Frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.
  2. 2:  This step checks for a high input signal from the mass air flow (MAF) sensor.
  3. 3:  This step checks for a low input signal from the MAF sensor.
  4. 6:  This step is looking for MAF sensor output on the MAF signal high circuit. Air movement around the sensor's hot wire element can cause some fluctuation in the voltage being measured.
DTC P0100

Step Action Values Yes No
Schematic Reference:  Engine Controls Schematics 
1  Did you perform the Diagnostic System Check-Engine Controls? - Go to Step 2  Go to Diagnostic System Check - Engine Controls
2  Select the MAF sensor parameter on the scan tool.
Is the MAF sensor value more than or equal to the specified value?		 185.0 g/s Go to Step 7  Go to Step 3 
3  Observe the MAF sensor parameters the scan tool.
Is the MAF sensor less than or equal to the specified value?		 0.45 g/s Go to Step 5  Go to Step 4 
4
  1. Clear the DTC Information with the scan tool.
  2. Operate the vehicle within the Freeze Frame conditions as specified.
Does a DTC P0100 set?		 - Go to Step 2  Go to Intermittent Conditions
5
  1. Turn OFF the ignition.
  2. Disconnect the MAF sensor electrical connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the ignition positive voltage circuit with a test lamp connected to ground.
Is the test lamp illuminated?		 - Go to Step 6  Go to Step 10 
6 
  1. Turn OFF the ignition.
  2. Connect the MAF sensor electrical connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Backprobe the MAF signal high circuit at the PCM with a DMM connected to ground.
Is the MAF signal high voltage within the specified range?		 0.5-3.0 V Go to Step 11  Go to Step 12 
7
  1. Turn OFF the ignition.
  2. Disconnect the MAF sensor electrical connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a test lamp from B+ to the MAF signal low circuit.
Does the test lamp illuminate?		 - Go to Step 8  Go to Step 9 
8 Measure the voltage of the MAF signal high circuit at the MAF sensor connector with a DMM connected to ground.
Is the MAF signal high circuit voltage more than the specified value?		 0.2 V Go to Step 13  Go to Step 15 
9
  1. Test for an open in the MAF sensor signal low circuit.
  2. Repair as necessary. Refer to Wiring Repairs in Wiring Systems.
Did you find and correct a condition?		 - Go to Step 18  Go to Step 14 
10 Repair the open in the MAF sensor ignition positive voltage circuit. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 - Go to Step 18  -
11
  1. Remove the MAF sensor from the air cleaner housing. Refer to Mass Air Flow (MAF) Sensor Replacement .
  2. Continue to backprobe the MAF signal high circuit at the PCM with the DMM.
  3. Observe the voltage on the MAF signal high circuit while blowing gently into the MAF sensor orifice.
Did the signal high circuit voltage increase when blowing air into the sensor orifice?		 - Go to Step 14  Go to Step 15 
12
  1. Test for an open or a short to ground in the MAF signal high circuit.
  2. Repair as necessary. Refer to Wiring Repairs in Wiring Systems.
Did you find and correct a condition?		 - Go to Step 18  Go to Step 15 
13
  1. Test for a short to voltage in the MAF signal high circuit.
  2. Repair as necessary. Refer to Wiring Repairs in Wiring Systems.
Did you find and correct a condition?		 - Go to Step 18  Go to Step 17 
14
  1. Test for an intermittent or a poor electrical connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
  2. Repair as necessary. Refer to Wiring Repairs in Wiring Systems.
Did you find and correct a condition?		 - Go to Step 18  Go to Step 17 
15
  1. Test for an intermittent or a poor electrical connection at the MAF sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
  2. Repair as necessary. Refer to Wiring Repairs in Wiring Systems.
Did you find and correct a condition?		 - Go to Step 18  Go to Step 16 
16 Replace the MAF sensor. Refer to Mass Air Flow (MAF) Sensor Replacement .
Did you complete the replacement?		 - Go to Step 18  -
17 Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement .
Did you complete the replacement?		 - Go to Step 18  -
18
  1. Use the scan tool in order to clear the DTCs.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
Does the DTC run and pass?		 - Go to Step 19  Go to Step 2 
19 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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