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Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1138 (Engine Controls Diagnosis - 3.6L (Ly7) (DTC P0008 - DTC P0133)) >> Diagnostic Trouble Codes >> DTC P0102 >> Test Description

Test Description

WARNING: This page is about a different car, the 2004 Buick Rendezvous. 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. 4:  This step tests the ignition 1 voltage circuit. Repair the open or short to ground in the ignition 1 voltage circuit, if the test lamp does not illuminate.
  2. 5:  The ECM produces a measurable steady-state amperage that provides the 5-volt reference to the MAF sensor. If the amperage on the 5-volt reference circuit is less than 80 mA, test the 5-volt reference circuit for a short to ground, an open, or a high resistance.
  3. 6:  This step tests the signal circuit of the MAF sensor.
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. Observe the MAF Sensor g/s parameter with a scan tool.
Does the parameter display more than the specified value?		 0.0 g/s Go to Step 3  Go to Step 4 
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 
  1. Turn OFF the ignition.
  2. Disconnect the mass air flow (MAF) sensor.
    3. NOTE: Do NOT use the low reference circuit in the component harness connector for this test. Damage to the control module may occur due to excessive current draw.
  3. Connect a test lamp between the ignition 1 voltage circuit of the MAF sensor and the engine control module (ECM) housing.
  4. Turn ON the ignition with the engine OFF.
Does the test lamp illuminate?		 - Go to Step 5  Go to Step 11 
5 
  1. Set-up a DMM to test amperage on the 400 mA scale.
  2. Measure the amperage from the 5-volt reference circuit of the MAF sensor to the ECM housing.
Is the amperage more than the specified value?		 80 mA Go to Step 6  Go to Step 7 
6 
  1. Turn OFF the ignition.
  2. Connect a 3-amp fused jumper wire between the signal circuit of the MAF sensor and the 5-volt reference circuit of the MAF sensor.
  3. Turn ON the ignition, with the engine OFF.
  4. Observe the MAF sensor voltage parameter with a scan tool.
Is the voltage within the specified range?		 4.8-5.2 V Go to Step 9  Go to Step 8 
7
  1. Turn OFF the ignition.
  2. Disconnect the ECM.
    3. IMPORTANT: The 5-volt reference circuits are internally and externally connected at the controller. Other sensors that share the 5-volt reference circuit may also have DTCs set. Disconnecting a sensor on the shared 5-volt reference circuit may isolate a shorted sensor. Review the electrical schematic and diagnose the shared circuits and sensors.
  3. Test the 5-volt reference circuit of the MAF sensor and all shared 5-volt reference circuits for the following:
    • An open
    • A short to ground
    • High resistance
Refer to Circuit Testing and Wiring Repairs in Wiring Systems.Did you find and correct the condition?		 - Go to Step 14  Go to Step 10 
8
  1. Turn OFF the ignition.
  2. Disconnect the ECM.
  3. Test the signal circuit of the MAF sensor for the following:
    • An open
    • A short to ground
    • High resistance
Refer to Circuit Testing and Wiring Repairs in Wiring Systems.Did you find and correct the condition?		 - Go to Step 14  Go to Step 10 
9 Test for an intermittent and for a poor connection at the MAF sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 14  Go to Step 12 
10 Test for an intermittent and for a poor connection at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 14  Go to Step 13 
11
  1. Repair the short to ground or the open in the ignition 1 voltage circuit of the MAF sensor. Refer to Wiring Repairs in Wiring Systems.
  2. Replace the fuse if necessary.
Did you complete the repair?		 - Go to Step 14  -
12 Replace the MAF sensor. Refer to Mass Air Flow (MAF)/Intake Air Temperature (IAT) Sensor Replacement .
Did you complete the replacement?		 - Go to Step 14  -
13 Replace the ECM. Refer to Engine Control Module (ECM) Replacement .
Did you complete the replacement?		 - Go to Step 14  -
14
  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 15 
15 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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