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Home >> Buick >> 2007 >> Allure CXS >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System & Fuel System - 3.6L - DTC P0008 To P0133 >> DTC P0101 >> Test Description
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Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. 3:  A circuit failure may cause this DTC to set. If DTC P0102 or P0103 are set, diagnose DTC P0102 or P0103 first.
  2. 6:  This step tests for high resistance in the ignition 1 voltage circuit of the MAF sensor. If the DMM does not display near battery voltage there is high resistance in the circuit.
  3. 8:  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 an open or a high resistance.
  4. 9:  This step tests for high resistance in the signal circuit of the MAF sensor.
  5. 10:  This step tests for high resistance in the low reference circuit of the MAF/intake air temperature (IAT) sensor. The MAF sensor and the IAT sensor share the low reference circuit. If there is a condition with the low reference circuit, a MAF and IAT sensor DTC may set. The ECM must be completely powered down to obtain an accurate resistance reading. It may take up to 30 minutes for the ECM to power down after the ignition key is removed. Removal of the ECM fuse, or the PCM/ETC fuse, allows the ECM to power down completely.
  6. 15:  Inspect the MAF/IAT sensor connector for water intrusion, corrosion, and bent or damaged terminals.
  7. 16:  Inspect the ECM connectors for water intrusion, corrosion, and bent or damaged terminals.
DTC P0101

Step Action Values Yes No
Schematic Reference:  Engine Controls Schematics 
Connector End View Reference:  Engine Control Module Connector End Views  or  Engine Controls 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 you were sent here from a fuel trim DTC, go to step 5 of this diagnostic procedure.
  1. Start the engine.
  2. Observe the Diagnostic Trouble Code (DTC) Information with a scan tool.
Does the DTC fail this ignition?		 - Go to Step 3  Go to Step 4 
3  Is DTC P0102 or DTC P0103 also set? - Go to DTC P0102  or DTC P0103  Go to Step 5 
4
  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 5  Go to Diagnostic Aids
5 Inspect for the following conditions:
  • An engine vacuum leak
  • An air leak in the intake air duct between the mass air flow (MAF) sensor and the throttle body
  • A plugged or collapsed intake air duct
  • Objects that block the MAF sensor air inlet
  • An air filter element that is restricted
  • A restricted throttle plate or for carbon build-up around the throttle plate
  • An unseated engine oil dip stick
  • A loose or missing engine oil fill cap
  • An over filled crankcase

Did you find and correct the condition?		 - Go to Step 20  Go to Step 6 
6 
  1. Turn OFF the ignition.
  2. Disconnect the MAF/intake air temperature (IAT) sensor.
  3. Turn ON the ignition, with the engine OFF.
    4. 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.
    IMPORTANT: Use the J 35616-200  Test Light-Probe Kit for this test. See Special Tools . If the J 35616-200  is not available, use a test lamp that measures more than 20 ohms. See Special Tools .
  4. Connect a test lamp between the ignition 1 voltage circuit of the MAF sensor and the engine control module (ECM) housing.
  5. Connect a DMM to the probe of the test lamp and the ECM housing. Refer to Measuring Voltage Drop .
Is the voltage at the specified value?		 B+ Go to Step 7  Go to Step 17 
7 Measure the voltage between the 5-volt reference circuit of the MAF sensor and the ECM housing, with a DMM.
Is the voltage more than specified value?		 5.2 V Go to Step 12  Go to Step 8 
8 
  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 9  Go to Step 13 
9 
  1. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the MAF sensor and the signal circuit of the MAF sensor.
  2. 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 10  Go to Step 11 
10 
  1. Turn OFF the ignition.
  2. Remove the ECM fuse, or the PCM/ETC fuse, from the underhood electrical center.
    3. NOTE: Do NOT use a test lamp to test the continuity of the circuit. Damage to the control module may occur due to excessive current draw.
  3. Measure the resistance from the low reference circuit of the MAF/IAT sensor to the ECM housing, with a DMM.
Is the resistance less than the specified value?		 5 Ω Go to Step 15  Go to Step 14 
11 Test the signal circuit of the MAF sensor for a high resistance. Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?		 - Go to Step 20  Go to Step 16 
12
IMPORTANT: The engine control module (ECM) for this engine is not equipped with 5-volt reference DTCs. 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.
Test the 5-volt reference circuit of the MAF sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs .Did you find and correct the condition?		 - Go to Step 20  Go to Step 16 
13
IMPORTANT: The engine control module (ECM) for this engine is not equipped with 5-volt reference DTCs. 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.
Test the 5 volt reference circuit of the MAF sensor for a high resistance. Refer to Circuit Testing and Wiring Repairs .Did you find and correct the condition?		 - Go to Step 20  Go to Step 16 
14 Test the low reference circuit of the MAF/IAT sensor for a high resistance. Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?		 - Go to Step 20  Go to Step 16 
15  Test for shorted terminals and poor connections at the MAF/IAT sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?		 - Go to Step 20  Go to Step 18 
16  Test for shorted terminals and poor connections at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?		 - Go to Step 20  Go to Step 19 
17 Repair the high resistance in the ignition 1 voltage circuit of the MAF sensor. Refer to Wiring Repairs .
Did you complete the repair?		 - Go to Step 20  -
18 Replace the MAF/IAT sensor. Refer to Mass Airflow Sensor/Intake Air Temperature Sensor Replacement .
Did you complete the replacement?		 - Go to Step 20  -
19 Replace the ECM. Refer to Control Module References for replacement, setup, and programming.
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 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
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