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Home >> Buick >> 2004 >> Century Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls (DTC P0030 To P0138) >> Engine Controls Diagnosis >> DTC P0107 >> Test Description
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Test Description

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

  1. 6:  The measurement noted in this step will be used in subsequent steps if the measurement is not less than the specified value.
  2. 7:  This step calculates the resistance in the 5-volt reference circuit.
P0107- MAP Sensor Circuit Low Voltage

Step Action Values Yes No
Schematic Reference:  Engine Controls Schematics 
Connector End View Reference:  Engine Controls Connector End Views  or  Powertrain Control Module (PCM) 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 with the scan tool.
Is DTC P0641 also set?		 - Go to DTC P0641 Go to Step 3 
3 Observe the manifold absolute pressure (MAP) sensor parameter with a scan tool.
Is the voltage less than the specified value?		 0.1 V Go to Step 5  Go to Step 4 
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 Intermittent Conditions
5 Test for an intermittent and for a poor connection at the MAP 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 15  Go to Step 6 
6 
  1. Turn OFF the ignition.
  2. Disconnect the MAP sensor electrical connector.
  3. Turn on the ignition, with the engine OFF.
  4. Measure the voltage from the 5-volt reference circuit of the MAP sensor to a good ground, with a DMM. Note the measurement as "Supply voltage".
Is the voltage more than the specified value?		 4.8 V Go to Step 7  Go to Step 9 
7 
  1. Connect a test lamp and a DMM in series between the 5-volt reference circuit and the low reference circuit of the MAP sensor at the harness connector.
  2. Measure the amperage with the DMM. Note the measurement as "Amperage".
  3. Remove the DMM from the circuit.
  4. Connect the test lamp between the 5-volt reference circuit and the low reference circuit of the MAP sensor, at the harness connector.
  5. Measure the voltage from the 5-volt reference circuit at the test lamp to a good ground, with the DMM. Note the measurement as "Load voltage drop".
    6. IMPORTANT: Before any calculations are performed, ensure that all measurements are converted to like units. For example, volts/amps or millivolts/milliamps.
  6. Subtract the "Load voltage drop" from the "Supply voltage". Note the result as "Supply voltage drop".
  7. Divide the "Supply voltage drop" by the "Amperage".
Is the result more than the specified value?		 5 ohm Go to Step 10  Go to Step 8 
8
  1. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the MAP sensor and the signal circuit of the MAP sensor.
  2. Observe the MAP sensor parameter with the scan tool.
Is the voltage more than the specified value?		 4.9 V Go to Step 13  Go to Step 11 
9 Test the 5-volt reference circuit between the powertrain control module (PCM) and MAP sensor for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 15  Go to Step 12 
10 Test the 5-volt reference circuit between the PCM and the MAP sensor for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 15  Go to Step 12 
11 Test the MAP sensor signal circuit between the PCM and the MAP sensor for the following conditions:
  • A short to ground
  • An open
  • High resistance

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 15  Go to Step 12 
12 Test for an intermittent and for a poor connection at the PCM. 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 15  Go to Step 14 
13 Replace the MAP sensor. Refer to Manifold Absolute Pressure (MAP) Sensor Replacement .
Did you complete the replacement?		 - Go to Step 15  -
14 Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement .
Did you complete the replacement?		 - Go to Step 15  -
15
  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 16 
16 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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