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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1074 (Engine Controls Diagnosis - 6.6L (LLY) (DTC P0653 To DTC P2228)) >> Diagnosis >> DTC P2227 >> Test Description

Test Description

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. 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. 3:  This step tests the ability of the boost pressure sensor to correctly indicate barometric pressure.
  2. 8:  This step tests the circuits and the controller output.
  3. 14:  This step test the circuits and the controller output.
DTC P2227

Step Action Values Yes No
Schematic Reference:  Engine Controls Schematics 
Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls 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. Observe and record the BARO parameter with a scan tool.
  3. Compare the barometric pressure (BARO) value to the range specified in the altitude vs. barometric pressure table. Refer to Altitude vs Barometric Pressure .
Is the BARO parameter within the range specified?		 - Go to Step 3  Go to Step 7 
3 
  1. Observe and record the Boost Pressure Sensor parameter with a scan tool.
  2. Compare the Boost Pressure Sensor value to the range specified in the altitude vs. barometric pressure table. Refer to Altitude vs Barometric Pressure .
Is the Boost Pressure Sensor parameter within the range specified?		 - Go to Step 4  Go to Step 13 
4
  1. Connect a J 23738-A  Mityvac to the BARO sensor port.
  2. Observe the BARO parameter with a scan tool.
  3. Apply vacuum with the J 23738-A  until 10 inches Hg is reached.
Does the BARO parameter decrease?		 - Go to Step 5  Go to Step 24 
5
  1. Start the engine.
  2. Operate the vehicle, at a consistent altitude, within the Conditions for Running the DTC.
  3. Observe the BARO parameter with a scan tool.
Does the BARO parameter change more than the specified value?		 15 kPa Go to Step 7  Go to Step 6 
6
  1. Operate the vehicle, at a consistent altitude, within the Conditions for Running the DTC.
  2. Observe the Boost Pressure Sensor parameter and the BARO parameter with a scan tool.
Is the difference between the Boost Pressure Sensor parameter and the BARO parameter more than the specified value?		 15 kPa Go to Step 13  Go to Intermittent Conditions
7 Test for an intermittent and for a poor connection at the BARO sensor connector. 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 27  Go to Step 8 
8 
  1. Disconnect the BARO sensor.
  2. Measure the amperage between the 5-volt reference circuit and the low reference circuit, at the BARO sensor connector, with a DMM.
Is the amperage more than the specified value?		 170 mA Go to Step 9  Go to Step 10 
9
  1. Connect a jumper wire between the 5-volt reference circuit and the BARO sensor signal circuit at the BARO sensor connector.
  2. Observe the BARO parameter with a scan tool.
Is the pressure more than the specified value?		 205 kPa Go to Step 24  Go to Step 19 
10 Test for an intermittent and for a poor connection at the engine control module (ECM). 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 27  Go to Step 11 
11
  1. Disconnect the ECM.
  2. Measure the resistance of the 5-volt reference circuit between the BARO sensor and the ECM, with a DMM.
Is the resistance more than the specified value?		 5 ohm Go to Step 23  Go to Step 12 
12 Measure the resistance of the low reference circuit between the BARO sensor and the ECM, with a DMM.
Is the resistance more than the specified value?		 5 ohm Go to Step 23  Go to Step 26 
13 Test for an intermittent and for a poor connection at the boost pressure sensor connector. 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 27  Go to Step 14 
14 
  1. Disconnect the boost pressure sensor.
  2. Measure the amperage between the 5-volt reference circuit and the low reference circuit, at the boost pressure sensor connector, with a DMM.
Is the amperage more than the specified value?		 170 mA Go to Step 15  Go to Step 16 
15
  1. Disconnect the ECM.
  2. Measure the resistance of the boost pressure sensor signal circuit between the boost pressure sensor and the ECM, with a DMM.
Is the resistance more than the specified value?		 5 ohm Go to Step 23  Go to Step 20 
16 Test for an intermittent and for a poor connection at the ECM. 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 27  Go to Step 17 
17
  1. Disconnect the ECM.
  2. Measure the resistance of the 5-volt reference circuit between the boost pressure sensor and the ECM, with a DMM.
Is the resistance more than the specified value?		 5 ohm Go to Step 23  Go to Step 18 
18 Measure the resistance of the low reference circuit between the boost pressure sensor and the ECM, with a DMM.
Is the resistance more than the specified value?		 5 ohm Go to Step 23  Go to Step 26 
19 Test for an intermittent and for a poor connection at the ECM. 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 27  Go to Step 21 
20
  1. Connect the ECM.
  2. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the boost sensor and the signal circuit of hte boost sensor.
  3. Turn ON the ignition, with the engine OFF.
  4. Observe the Boost Pressure Sensor parameter with a scan tool.
Is the Boost Pressure Sensor parameter more than the specified value		 254 kPa (36 PSI) Go to Step 25  Go to Step 22 
21
  1. Disconnect the ECM.
  2. Measure the resistance of the BARO sensor signal circuit between the BARO sensor and the ECM, with a DMM.
Is the resistance more than the specified value?		 5 ohm Go to Step 23  Go to Step 26 
22 Test for an intermittent and for a poor connection at the ECM. 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 27  Go to Step 26 
23 Repair the high resistance in the circuit. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 - Go to Step 27  -
24 Replace the BARO sensor. Refer to Barometric Pressure (BARO) Sensor Replacement .
Did you complete the replacement?		 - Go to Step 27  -
25 Replace the boost pressure sensor. Refer to Boost Pressure Sensor Replacement .
Did you complete the replacement?		 - Go to Step 27  -
26 Replace the ECM. Refer to Engine Control Module (ECM) Replacement .
Did you complete the replacement?		 - Go to Step 27  -
27
  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 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 System OK
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