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Home >> Chevrolet >> 2005 >> Classic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (DTC P0106-P0300) >> Diagnosis >> DTC P0106 >> Test Description
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Test Description

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

  1. 9:  This step tests the ability of the MAP sensor to respond to a pressure change.
  2. 15:  The measurement noted in this step will be used in subsequent steps if the measurement is not more than the specified value.
  3. 18:  This step calculates the resistance in the 5-volt reference circuit of the MAP sensor.
  4. 19:  This step calculates the resistance in the low reference circuit of the MAP sensor.
  5. 21:  The measurement noted in this step will be used in subsequent steps if the measurement does not exceed the specified value.
  6. 23:  This step calculates the resistance in the 5-volt reference circuit of the TP sensor.
  7. 24:  This step calculates the resistance in the low reference circuit of the TP sensor.
DTC P0106

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 - Vehicle? - Go to Step 2  Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2 Inspect for the following conditions:
  • Any disconnected, damaged, or incorrectly routed vacuum hoses
  • The manifold absolute pressure (MAP) sensor disconnected from vacuum source
  • Any restrictions in the MAP sensor vacuum source
  • Any intake manifold vacuum leaks

Did you find and correct the condition?		 - Go to Step 44  Go to Step 3 
3
  1. Turn ON the ignition, with the engine OFF.
  2. Observe the throttle position (TP) sensor voltage with a scan tool.
Is the voltage less than the specified value when the throttle is fully closed?		 0.85 V Go to Step 4  Go to Step 5 
4
  1. Observe the TP sensor angle with a scan tool.
  2. Monitor the scan tool while slowly depressing the accelerator pedal to the floor, then slowly release the pedal. Repeat the procedure several times.
Does the TP angle increase steadily when the accelerator pedal is depressed to more than the first specified value and decrease steadily, returning to less than the second specified value when the pedal is released?		 98%
1%		 Go to Step 6  Go to Step 21 
5 Inspect the throttle body for the following conditions:
  • A binding or damaged throttle cable
  • A damaged throttle blade
  • A binding or damaged cruise control cable

Did you find and correct the condition?		 - Go to Step 44  Go to Step 21 
6
IMPORTANT: The vehicle used for the comparison is not limited to the same type of vehicle as is being serviced. A vehicle known to provide an accurate reading is acceptable.
Do you have access to another vehicle in which the MAP sensor pressure can be observed with a scan tool?		 - Go to Step 7  Go to Step 8 
7
  1. Turn ON the ignition, with the engine OFF.
  2. Observe the MAP sensor pressure with a scan tool.
  3. Observe the MAP sensor pressure in the known good vehicle with a scan tool.
  4. Compare the values.
Is the difference between the values less than the specified value?		 3 kPa Go to Step 9  Go to Step 14 
8
IMPORTANT: The Altitude vs Barometric Pressure table indicates a pressure range for a given altitude under normal weather conditions. Weather conditions consisting of very low or very high pressure and/or very low or very high temperature may cause a reading to be slightly out of range.
  1. Turn ON the ignition, with the engine OFF.
  2. Observe the MAP sensor pressure with a scan tool. Refer to Altitude vs Barometric Pressure .
  3. The MAP sensor pressure should be within the range specified for your altitude.
Does the MAP sensor indicate the correct barometric pressure?		 - Go to Step 9  Go to Step 14 
9 
  1. Remove the MAP sensor from the engine vacuum source. Leave the MAP sensor connected to the engine harness.
  2. Connect a J 23738-A Mityvac to the MAP sensor.
  3. Observe the MAP sensor pressure with a scan tool.
  4. Apply vacuum with the J 23738-A until 5 inch Hg is reached.
Does the MAP sensor pressure change?		 - Go to Step 10  Go to Step 14 
10
  1. Observe the MAP sensor pressure with the scan tool.
  2. Apply vacuum with the J 23738-A in 1 inch Hg increments until 15 inch Hg is reached. Each 1 inch Hg should decrease the MAP sensor pressure by 3-4 kPa.
Is the decrease in MAP sensor pressure consistent?		 - Go to Step 11  Go to Step 14 
11 Apply vacuum with the J 23738-A until 20 inch Hg is reached.
Is the MAP sensor pressure less than the specified value?		 34 kPa Go to Step 12  Go to Step 14 
12 Disconnect the J 23738-A from the MAP sensor.
Does the MAP sensor pressure return to the value observed in Step 7 or Step 8?		 - Go to Step 13  Go to Step 41 
13 Test for the following conditions:
Did you find and correct the condition?		 - Go to Step 44  Go to Diagnostic Aids
14
  1. Turn OFF the ignition.
  2. Disconnect the MAP sensor electrical connector.
  3. Turn ON the ignition.
  4. Observe the MAP sensor voltage with a scan tool.
Is the voltage less than the specified value?		 0.2 V Go to Step 15  Go to Step 28 
15  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?		 5.2 V Go to Step 26  Go to Step 16 
16 Is the voltage more than the specified value? 4.8 V Go to Step 17  Go to Step 27 
17
  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".
Is the amperage equal to the specified value?		 0 mA Go to Step 30  Go to Step 18 
18 
  1. Remove the DMM from the circuit.
  2. Connect the test lamp between the 5-volt reference circuit and the low reference circuit of the MAP sensor at the harness connector.
  3. 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".
    4. IMPORTANT: Before any calculations are performed, ensure that all measurements are converted to like units. For example, volts/amps or millivolts/milliamps.
  4. Subtract the "Load voltage drop" from the "Supply voltage". Note the result as "Supply voltage drop".
  5. Divide the "Supply voltage drop" by the "Amperage".
Is the result more than the specified value?		 5 ohm Go to Step 29  Go to Step 19 
19 
  1. Measure the voltage from the low reference circuit of the MAP sensor at the test lamp to a good ground with the DMM. Note the result as "Low reference voltage drop".
    2. IMPORTANT: Before any calculations are performed, ensure that all measurements are converted to like units. For example, volts/amps or millivolts/milliamps.
  2. Divide the "Low reference voltage drop" by the "Amperage".
Is the result more than the specified value?		 5 ohm Go to Step 31  Go to Step 20 
20
  1. Remove the test lamp.
  2. 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.
  3. Observe the MAP Sensor parameter with the scan tool.
Is the voltage more than the specified value?		 4.9 V Go to Step 37  Go to Step 32 
21 
  1. Remove the air cleaner outlet resonator. Refer to Air Cleaner Outlet Resonator Replacement .
  2. Disconnect the TP sensor.
  3. Measure the voltage from the 5-volt reference circuit of the TP sensor to a good ground with a DMM. Note the measurement as "Supply voltage".
Is the voltage more than the specified value?		 5.2 V Go to Step 33  Go to Step 22 
22 Is the voltage more than the specified value? 4.8 V Go to Step 23  Go to Step 25 
23 
  1. Connect a test lamp and a DMM in series between the 5-volt reference circuit and the low reference circuit of the TP 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 TP 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 34  Go to Step 24 
24 
  1. Measure the voltage from the low reference circuit of the TP sensor at the test lamp to a good ground with the DMM. Note the result as "Low reference voltage drop".
    2. IMPORTANT: Before any calculations are performed, ensure that all measurements are converted to like units. For example, volts/amps or millivolts/milliamps.
  2. Divide the "Low reference voltage drop" by the "Amperage".
Is the result more than the specified value?		 5 ohm Go to Step 35  Go to Step 38 
25
  1. Leave the DMM connected.
  2. Disconnect the air conditioning (A/C) refrigerant pressure sensor and the fuel tank pressure (FTP) sensor, one at a time.
  3. Observe the DMM each time a sensor is disconnected.
Does the voltage measure more than the specified value after either of the sensors are disconnected?		 4.8 V Go to Step 40  Go to Step 36 
26 Test the 5-volt reference circuit of the MAP sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 44  Go to Step 43 
27 Test the 5-volt reference circuit of the MAP sensor for a short to ground or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 44  Go to Step 39 
28 Test the MAP sensor signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 44  Go to Step 43 
29 Test the 5-volt reference circuit of 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 44  Go to Step 39 
30 Test the MAP sensor low reference circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 44  Go to Step 39 
31 Test the MAP sensor low reference circuit for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 44  Go to Step 39 
32 Test the MAP sensor signal circuit for the following conditions:
  • 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 44  Go to Step 39 
33 Test the 5-volt reference circuits of the following sensors for a short to voltage:
  • The TP sensor
  • The A/C refrigerant pressure sensor
  • The FTP sensor

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 44  Go to Step 43 
34 Test all of the 5-volt reference circuit of the TP sensor for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 44  Go to Step 39 
35 Test the low reference circuit of the TP sensor for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 44  Go to Step 39 
36 Test the 5-volt reference circuits of the following sensors for a short to ground:
  • The TP sensor
  • The A/C refrigerant pressure sensor
  • The FTP sensor

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 44  Go to Step 43 
37 Test for poor connections 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 44  Go to Step 41 
38 Test for poor connections at the TP 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 44  Go to Step 42 
39 Test for poor connections at the powertrain control module (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 44  Go to Step 43 
40 Replace the component for which the voltage changed. Refer to Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement in Heating, Ventilation, and Air Conditioning or Fuel Tank Pressure Sensor Replacement .
Did you complete the replacement?		 - Go to Step 44  -
41 Replace the MAP sensor. Refer to Manifold Absolute Pressure (MAP) Sensor Replacement .
Did you complete the replacement?		 - Go to Step 44  -
42 Replace the TP sensor. Refer to Throttle Position (TP) Sensor Replacement .
Did you complete the replacement?		 - Go to Step 44  -
43 Replace the PCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.
Did you complete the replacement?		 - Go to Step 44  -
44
  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 45 
45 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 in Vehicle DTC Information System OK
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