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Test Description

WARNING: This page is about a different car, the 2004 Pontiac Grand Prix. 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 tests the ability of the BARO sensor to correctly indicate barometric pressure. The value shown for the BARO sensor varies with altitude and weather conditions.
  2. 7:  This step tests the ability of the MAP sensor to correctly indicate barometric pressure.
  3. 8:  This step tests for a sensor that is stuck in range.
  4. 14:  This step calculates the resistance in the 5-volt reference circuit.
  5. 15:  This step calculates the resistance in the low reference circuit.
  6. 18:  This step calculates the resistance in the 5-volt reference circuit.
  7. 19:  This step calculates the resistance in the low reference circuit.
DTC P0069

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. Turn ON the ignition, with the engine OFF.
  2. Monitor the DTC information with the scan tool.
Is DTC P0107, P0108, P0641, P0651, P2228, or P2229 also set?		 - Go to Diagnostic Trouble Code (DTC) List Go to Step 3 
3
  1. Turn OFF the ignition.
  2. Remove the barometric pressure (BARO) sensor and the manifold absolute pressure (MAP) sensor.
  3. Inspect each sensor for a plugged port.
Did you find and correct the condition?		 - Go to Step 31  Go to Step 4 
4
IMPORTANT: The vehicle that is used for a comparison is not limited to the same type of vehicle that is being serviced. A vehicle known to provide an accurate BARO reading is acceptable.
Do you have access to another vehicle in which the BARO parameter can be observed with a scan tool?		 - Go to Step 5  Go to Step 6 
5 
    IMPORTANT: References to the known good vehicle are made in this step only.
  1. Turn ON the ignition, with the engine OFF.
  2. Observe the BARO parameter with a scan tool.
  3. Turn ON the ignition of the known good vehicle, with the engine OFF.
  4. Observe the BARO parameter of the known good vehicle with a scan tool.
  5. Compare the values.
Is the difference between the values less than the specified value?		 3 kPa Go to Step 7  Go to Step 12 
6
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 BARO parameter with a scan tool. Refer to Altitude vs Barometric Pressure .
  3. The BARO parameter should be within the range specified for your altitude.
Does the BARO sensor indicate the correct barometric pressure?		 - Go to Step 7  Go to Step 12 
7 
  1. Observe the BARO parameter and the MAP Sensor parameter with a scan tool.
  2. Compare the values.
Is the difference between the values less than the specified value?		 3 kPa Go to Step 8  Go to Step 17 
8 
  1. Turn OFF the ignition.
  2. Connect a J 23738-A  Mityvac vacuum pump to the BARO sensor port.
  3. Turn ON the ignition, with the engine OFF.
  4. Monitor the BARO parameter with the scan tool.
  5. Apply vacuum with the J 23738-A  SLOWLY 1 inch Hg at a time. Each inch of vacuum should result in a 3-4 kPa drop in the BARO sensor pressure.
  6. Increase the vacuum to 20 inches Hg.
Does the BARO parameter decrease smoothly through the test?		 - Go to Step 9  Go to Step 12 
9 Disconnect the J 23738-A  from the BARO sensor port.
Does the BARO sensor pressure return to the original value that was observed in step 5 or 6?		 - Go to Step 10  Go to Step 29 
10
  1. Turn OFF the ignition.
  2. Remove the MAP sensor from the vacuum source, leaving the harness connected.
  3. Connect a J 23738-A  Mityvac vacuum pump to the MAP sensor port.
  4. Turn ON the ignition, with the engine OFF.
  5. Monitor the MAP sensor parameter with the scan tool.
  6. Apply vacuum with the J 23738-A  SLOWLY 1 inch Hg at a time. Each inch of vacuum should result in a 3-4 kPa drop in the MAP sensor pressure.
  7. Increase the vacuum to 20 inches Hg.
Does the MAP sensor parameter decrease smoothly through the test?		 - Go to Step 11  Go to Step 17 
11 Disconnect the J 23738-A  from the MAP sensor port.
Does the MAP sensor pressure return to the original value that was observed in step 7?		 - Go to Intermittent Conditions Go to Step 28 
12 Test for an intermittent and for a poor connection at the BARO 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 31  Go to Step 13 
13
  1. Disconnect the BARO sensor harness connector.
  2. Measure the voltage from the 5-volt reference circuit of the BARO sensor to a good ground with a DMM. Note the measurement as "supply voltage."
  3. Connect a test lamp and a DMM in series between the 5-volt reference circuit and the low reference circuit of the BARO sensor at the harness connector.
  4. Measure the amperage with the DMM. Note the measurement as amperage.
Is the amperage at the specified value?		 0 mA Go to Step 21  Go to Step 14 
14 
  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 BARO 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. 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 23  Go to Step 15 
15 
  1. Measure the voltage from the low reference circuit of the BARO sensor at the test lamp to a good ground with the DMM. Note the result as "low reference voltage drop."
  2. Divide the "low reference voltage drop" by the amperage.
Is the result more than the specified value?		 5 ohm Go to Step 21  Go to Step 16 
16
  1. Remove the test lamp.
  2. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the BARO sensor and the signal circuit of the BARO sensor.
  3. Observe the BARO parameter with the scan tool.
Is the pressure more than the specified value?		 198 kPa Go to Step 29  Go to Step 22 
17 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 31  Go to Step 18 
18 
  1. Disconnect the MAP sensor harness connector.
  2. 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."
  3. 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.
  4. Measure the amperage with the DMM. Note the measurement as amperage.
  5. Remove the DMM from the circuit.
  6. Connect the test lamp between the 5-volt reference circuit and the low reference circuit of the MAP sensor at the harness connector.
  7. 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."
  8. Subtract the "load voltage drop" from the "supply voltage". Note the result as "supply voltage drop."
  9. Divide the "supply voltage drop" by the amperage.
Is the result more than the specified value?		 5 ohm Go to Step 26  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. Divide the "low reference voltage drop" by the amperage.
Is the result more than the specified value?		 5 ohm Go to Step 24  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 at the harness connector.
  3. Observe the MAP Sensor parameter with the scan tool.
Is the voltage more than the specified value?		 4.75 V Go to Step 28  Go to Step 25 
21 Test the low reference circuit of the BARO sensor for high resistance or an open. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 31  Go to Step 27 
22 Test the signal circuit of the BARO sensor for high resistance. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 31  Go to Step 27 
23 Test the 5-volt reference circuit of the BARO sensor for high resistance. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 31  Go to Step 27 
24 Test the low reference circuit of the MAP sensor for high resistance or an open. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 31  Go to Step 27 
25 Test the signal circuit of the MAP sensor for high resistance. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 31  Go to Step 27 
26 Test the 5-volt reference circuit of the MAP sensor for high resistance. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 31  Go to Step 27 
27 Test for an intermittent and for a poor connection 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 31  Go to Step 30 
28 Replace the MAP sensor. Refer to Manifold Absolute Pressure (MAP) Sensor Replacement (L26) or Manifold Absolute Pressure (MAP) Sensor Replacement (L32) .
Did you complete the replacement?		 - Go to Step 31  -
29 Replace the BARO sensor. Refer to Barometric Pressure (BARO) Sensor Replacement .
Did you complete the replacement?		 - Go to Step 31  -
30 Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement .
Did you complete the replacement?		 - Go to Step 31  -
31
  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 32 
32 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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