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Home >> Chevrolet >> 2006 >> Cobalt LTZ >> Repair and Diagnosis >> External Pages >> Different car >> Section 691 (Engine Controls And Fuel - 2.0L - DTC P0017 To DTC P0123) >> DTC P0102 >> Test Description

Test Description

WARNING: This page is about a different car, the 2007 Chevrolet Cobalt. 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. 5:  This step will determine if any mechanical faults have caused this DTC to set.
  2. 7:  This voltage drop test will determine if high resistance has caused this DTC to set.
  3. 9:  This step verifies the voltage signal from the PCM to the MAF sensor connector.
  4. 10:  This step tests the signal circuit of the MAF sensor for a short to another 5-volt reference circuit.
  5. 11:  This step will determine if the MAF sensor is able to generate a frequency signal.
  6. 13:  This step will determine which portion of the circuit or which component is shorted to ground.
  7. 16:  This step verifies that the signal circuit is not shorted to any other PCM circuit.
DTC P0102

Step Action Values Yes No
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Powertrain 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
  1. Start the engine.
  2. Select the Induction Data List.
  3. Observe the MAF Sensor parameter with a scan tool.
Is the MAF Sensor parameter less than the specified value?		 100 Hz Go to Step 4  Go to Step 3 
3
  1. Observe the Freeze Frame/Failure Records for this DTC.
  2. Turn OFF the ignition for 90 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. Observe the MAF Sensor parameter with a scan tool.
  2. Move the harness and the connector of the mass air flow (MAF)/intake air temperature (IAT) sensor.
Does the movement of the harness or the connector affect the MAF Sensor parameter?		 - Go to Step 19  Go to Step 5 
5 
  1. Turn OFF the ignition.
  2. Inspect for the following conditions:
    • A MAF/IAT sensor harness that it is routed too close to the following components:
    • A restricted or collapsed air intake duct
    • A misaligned or damaged air intake duct
    • Loose clamps on the air intake duct
    • A dirty or deteriorating air filter element
    • Water in the induction system
    • Any objects blocking or restricting the air inlet probe of the MAF/IAT sensor
    • Any contamination or debris on the sensing elements in the probe of the MAF/IAT sensor
Did you find and correct the condition?		 - Go to Step 27  Go to Step 6 
6 Inspect the fuse in the ignition 1 voltage circuit of the MAF sensor.
Is the fuse open?		 - Go to Step 13  Go to Step 7 
7 
  1. Turn ON the ignition, with the engine OFF.
  2. Measure the battery voltage with a DMM. Refer to Measuring Voltage .
  3. Disconnect the MAF/IAT sensor.
  4. Connect a test lamp between the ignition 1 voltage circuit of the MAF sensor and a good ground. Refer to Probing Electrical Connectors .
  5. Connect the DMM to the probe of the test lamp and a good ground. Refer to Measuring Voltage Drop and Circuit Testing .
Is the voltage within 1.5 volts of the specified value?		 B+ Go to Step 8  Go to Step 20 
8
IMPORTANT: All electrical components and accessories must be turned OFF.
  1. Turn OFF the ignition for 90 seconds to allow the control modules to power down.
  2. Measure the resistance from the ground circuit of the MAF sensor to a good ground with a DMM. Refer to Circuit Testing .
Is the resistance less than the specified value?		 5 Ω Go to Step 9  Go to Step 21 
9 
  1. Turn ON the ignition, with the engine OFF.
  2. Measure the voltage from the signal circuit of the MAF sensor to a good ground with a DMM. Refer to Circuit Testing .
Is the voltage within the specified range?		 4.9-5.2 V Go to Step 10  Go to Step 12 
10 
  1. Connect a 3-amp fused jumper wire between the signal circuit of the MAF sensor and a good ground. Refer to Circuit Testing .
  2. Start the engine.
  3. Observe the DTC Information with a scan tool.
Do any additional DTCs set?		 - Go to Step 23  Go to Step 11 
11 
  1. Turn OFF the ignition.
  2. Review the schematics for the MAF/IAT sensor.
  3. Connect a jumper wire between each of the 5 terminals of the MAF/IAT sensor harness connector and the corresponding 5 terminals of the MAF/IAT sensor. Refer to Probing Electrical Connectors .
  4. Start the engine and allow it to reach operating temperature.
  5. Measure the frequency from the signal circuit of the MAF sensor to a good ground with a DMM.
Does the DMM display a frequency within the specified range?		 1,600-2,500 Hz Go to Step 14  Go to Step 17 
12 Is the voltage less than the specified value? 4.9 V Go to Step 14  Go to Step 15 
13 
IMPORTANT: The ignition 1 voltage circuit of the MAF sensor is spliced to other components of the vehicle.
Test the spliced ignition 1 voltage circuits and components for a short to ground. Refer to the following procedures:Did you find and correct the condition?		 - Go to Step 27  -
14
  1. Turn OFF the ignition.
  2. Disconnect the powertrain control module (PCM).
  3. Test the signal circuit between the PCM and the MAF sensor for the following conditions:
    • A high resistance
    • An open circuit
    • A short to the IAT sensor 1 low reference circuit
    • A short to ground

      Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?		 - Go to Step 27  Go to Step 16 
15
IMPORTANT: Disconnecting the PCM connectors may eliminate the short to voltage if the signal circuit is shorted to another PCM circuit.
  1. Turn OFF the ignition.
  2. Disconnect the PCM.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage from the signal circuit of the MAF sensor to a good ground with a DMM. Refer to Circuit Testing .
Is the voltage more than the specified value?		 0 V Go to Step 22  Go to Step 16 
16 
  1. Turn OFF the ignition.
  2. Measure the resistance from the signal circuit of the MAF sensor to all other circuits at all PCM connectors with a DMM. Refer to Circuit Testing .
Is the resistance less than the specified value?		 ∞ Ω Go to Step 24  Go to Step 18 
17 Test for an intermittent and for a poor connection 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 27  Go to Step 25 
18 Test for an intermittent and for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?		 - Go to Step 27  Go to Step 26 
19 Repair the wiring or the connector as needed. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you complete the repair?		 - Go to Step 27  -
20 Repair the high resistance or the open in the MAF sensor ignition 1 voltage circuit. Refer to Wiring Repairs .
Did you complete the repair?		 - Go to Step 27  -
21 Repair the high resistance or the open in the MAF sensor ground circuit. Refer to Wiring Repairs .
Did you complete the repair?		 - Go to Step 27  -
22 Repair the short to voltage in the MAF sensor signal circuit. Refer to Wiring Repairs .
Did you complete the repair?		 - Go to Step 27  -
23 Repair the short between the MAF sensor signal circuit and the 5-volt reference circuit for which the DTC set. Refer to Wiring Repairs .
Did you complete the repair?		 - Go to Step 27  -
24 Repair the circuits that are shorted together. Refer to Wiring Repairs .
Did you complete the repair?		 - Go to Step 27  -
25 Replace the MAF/IAT sensor. Refer to Mass Airflow Sensor Replacement .
Did you complete the replacement?		 - Go to Step 27  -
26 Replace the PCM. Refer to Control Module References for replacement, setup, and programming.
Did you complete the replacement?		 - Go to Step 27  -
27
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 90 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 28 
28 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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