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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 991 (Engine Controls Diagnosis - 6.6L (Lb7) (DTCS P0016 To P0236)) >> Diagnosis >> DTC P0201-P0208 >> 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. 2:  This step verifies that the condition is not intermittent.
  2. 4:  This step determines which set of fuel injectors the circuit condition is affecting. If DTC P2146 is set, then a condition exists on cylinders 1, 4, 6, or 7. If DTC P2149 is set, then a condition exists on cylinders 2, 3, 5, or 8.
  3. 5:  This step tests if a ground is constantly being applied to the fuel injectors.
  4. 6:  This step isolates which circuit is causing the condition. If the DMM displays OL when a multi-way connector is disconnected, test the affected circuits for a short to ground.
  5. 7:  This step tests for an open circuit. If the DMM displays OL on all of the fuel injector circuits, the injector supply voltage circuit is open.
  6. 8:  This step tests for an open circuit. If the DMM displays OL on one of the fuel injector circuits, the fuel injector command circuit is open.
  7. 9:  This step tests for excessive resistance in a fuel injector circuit.
  8. 10:  This step is testing for a short between the injector supply voltage circuit and the fuel injector command circuit. If the resistance of the circuits is less than 0.3 ohms, test for a short between the circuits. If a short cannot be found, the fuel injector may be the cause of the condition. The normal fuel injector resistance is between 0.3-0.4 ohms.
  9. 11:  This step tests for a short to voltage on a fuel injector circuit. If the DMM displays battery voltage a short to voltage is the cause of the condition.
  10. 12:  This step isolates which circuit is causing the condition. If the DMM display changes to 0 volts when a multi-way connector is disconnected, test the disconnected circuits for a short to voltage.
  11. 13:  This step tests if a ground is constantly being applied to the fuel injectors.
  12. 14:  This step isolates which circuit is causing the condition. If the DMM displays OL when a multi-way connector is disconnected, test the affected circuits for a short to ground.
  13. 15:  This step tests for an open circuit. If the DMM displays OL on all of the fuel injector circuits, the injector supply voltage circuit is open.
  14. 16:  This step tests for an open circuit. If the DMM displays OL on one of the fuel injector circuits, the fuel injector command circuit is open.
  15. 17:  This step tests for excessive resistance in a fuel injector circuit.
  16. 18:  This step is testing for a short between the injector supply circuit and the fuel injector command circuit. If the resistance of the circuits is less than 0.3 ohms, test for a short between the circuits. If a short cannot be found, the fuel injector may be the cause of the condition. The normal fuel injector resistance is between 0.3-0.4 ohms.
  17. 19:  This step tests for a short to voltage on a fuel injector circuit. If the DMM displays battery voltage a short to voltage is the cause of the condition.
  18. 20:  This step isolates which circuit is causing the condition. If the DMM display changes to 0 volts when a multi-way connector is disconnected, test the disconnected circuits for a short to voltage.
DTC P0201-P0208

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  Observe the DTC information with a scan tool.
Are DTCs P0201, P0204, P0206, P0207, or P0202, P0203, P0205, P0208 set?		 - 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 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 4  Go to Intermittent Conditions
4  Is DTC P2146 also set? - Go to Step 13  Go to Step 5 
5 
CAUTION: Refer to High Voltage Caution in Cautions and Notices.
  1. Turn OFF the ignition.
    2. IMPORTANT: Refer to Engine Controls Component Views for fuel injector locations. Failure to identify the correct cylinder will result in misdiagnosis.
  2. Disconnect the fuel injection control module (FICM).
    3. IMPORTANT: Use the J 35616-94 adapters to probe the FICM connector.
  3. Measure the resistance between the injector supply voltage circuit for cylinders 2, 3, 5, and 8 and a known good ground with a DMM.
Does the DMM display OL?		 - Go to Step 7  Go to Step 6 
6  Disconnect each multi-way harness connector of the fuel injectors one at a time, while monitoring the DMM.
Does the DMM display OL when any of the fuel injector harness connectors are disconnected?		 - Go to Step 21  Go to Step 34 
7 
IMPORTANT:
  • The DMM and test leads must be calibrated to 0 ohms in order to prevent misdiagnosis. Use the J 39200 DMM to perform this test. Refer to the DMM User Manual for calibration procedure.
  • Use the J 35616-94 adapters to probe the FICM connector.
  • The temperature of the engine and injectors should be the same as when the DTC set.
Measure the resistance between the injector supply voltage circuit and the injector command circuits for cylinders 2, 3, 5, and 8 with a DMM.Does the DMM display OL for all of the circuits?		 - Go to Step 35  Go to Step 8 
8  Does the DMM display OL for any of the circuits? - Go to Step 23  Go to Step 9 
9  Does the DMM display a resistance above the specified value for any fuel injector circuit? 0.8 ohm Go to Step 26  Go to Step 10 
10  Does the DMM display a resistance below the specified value for any fuel injector circuit? 0.3 ohm Go to Step 28  Go to Step 11 
11 
  1. Turn ON the ignition, with the engine OFF.
    2. IMPORTANT: Use the J 35616-94 adapters to probe the FICM connector.
  2. Probe the injector supply voltage circuit for cylinders 2, 3, 5 and 8, with a DMM connected to ground.
Does the DMM display battery voltage?		 - Go to Step 12  Go to Step 29 
12  Disconnect each multi-way harness connector of the fuel injectors one at a time, while monitoring the DMM.
Does the DMM display the specified voltage when any of the fuel injector harness connectors are disconnected?		 0 volts Go to Step 32  Go to Step 31 
13 
CAUTION: Refer to High Voltage Caution in Cautions and Notices.
  1. Turn OFF the ignition.
    2. IMPORTANT: Refer to Engine Controls Component Views for fuel injector locations. Failure to identify the correct cylinder will result in misdiagnosis.
  2. Disconnect the FICM.
    3. IMPORTANT: Use the J 35616-94 adapters to probe the FICM connector.
  3. Measure the resistance between the injector supply voltage circuit for cylinders 1, 4, 6, and 7 and a known good ground with a DMM.
Does the DMM display OL?		 - Go to Step 15  Go to Step 14 
14  Disconnect each multi-way harness connector of the fuel injectors one at a time, while monitoring the DMM.
Does the DMM indicate OL when any of the fuel injector harness connectors are disconnected?		 - Go to Step 21  Go to Step 34 
15 
IMPORTANT:
  • The DMM and test leads must be calibrated to 0 ohms in order to prevent misdiagnosis. Refer to the DMM User Manual for calibration procedure.
  • Use the J 35616-94 adapters to probe the FICM connector.
  • The temperature of the engine and injectors should be the same as when the DTC set.
Measure the resistance between the injector supply voltage circuit and the injector command circuits for cylinders 1, 4, 6 and 7 with a DMM.Does the DMM display OL for all of the circuits?		 - Go to Step 35  Go to Step 16 
16  Does the DMM display OL for any of the circuits? - Go to Step 23  Go to Step 17 
17  Does the DMM display a resistance above the specified value for any fuel injector circuit? 0.8 ohm Go to Step 26  Go to Step 18 
18  Does the DMM display a resistance below the specified value for any fuel injector circuit? 0.3 ohm Go to Step 28  Go to Step 19 
19 
IMPORTANT: Use the J 35616-94 adapters to probe the FICM connector.
  1. Turn ON the ignition, with the engine OFF.
  2. Probe the injector supply voltage circuit for cylinders 1, 4, 6 and 7, with a DMM connected to ground.
Does the DMM display battery voltage?		 - Go to Step 20  Go to Step 29 
20  Disconnect each multi-way harness connector of the fuel injectors one at a time, while monitoring the DMM.
Does the DMM display the specified voltage when any of the fuel injector harness connectors are disconnected?		 0 volts Go to Step 32  Go to Step 31 
21 Measure the resistance from the fuel injector command circuit to ground at the FICM connector for the cylinder that caused the DMM to display OL.
Does the DMM display continuity?		 - Go to Step 33  Go to Step 22 
22
  1. Disconnect the harness from the fuel injector.
  2. Test for a short between each electrical connection of the fuel injector and the fuel injector housing with a DMM. Refer to Circuit Testing in Wiring Systems.
Is there continuity between either electrical post of the fuel injector and the fuel injector housing?		 - Go to Step 37  Go to Step 36 
23
  1. Disconnect the multi-way connector of the fuel injector that displayed OL.
  2. Test the command circuit of the fuel injector between the FICM and the multi-way connector, for the following conditions:
    • An open circuit
    • A poor connection
Refer to Connector Repairs or Wiring Repairs in Wiring Systems.Did you find and correct the condition?		 - Go to Step 39  Go to Step 24 
24 Test the injector voltage circuit of the fuel injector, between the multi-way connector and the splice, for the following conditions:
  • An open circuit
  • A poor connection

Refer to Connector Repairs or Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 39  Go to Step 25 
25 Test both of the fuel injector circuits between the fuel injector and the multi-way connector for an open. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 39  Go to Step 30 
26
  1. Disconnect the multi-way connector for the circuit with high resistance.
  2. Test for the following conditions:
    • Excessive resistance in the fuel injector circuits between the FICM and the multi-way connector
    • Poor connections at the multi-way connector of the fuel injector
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 39  Go to Step 27 
27 Test both of the fuel injector circuits between the fuel injector and the multi-way connector for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 39  Go to Step 30 
28 Test for a short between the injector supply voltage circuit and the fuel injector command circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 39  Go to Step 37 
29 Test for an intermittent and for a poor connection at the harness connector of the FICM. 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 39  Go to Step 38 
30 Test for an intermittent and for a poor connection at the harness connector of the fuel injector. 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 39  Go to Step 37 
31 Repair the short to voltage in the injector supply voltage circuit. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 - Go to Step 39  -
32 Repair the short to voltage in the fuel injector command circuit that changed to 0 volts on the DMM. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 - Go to Step 39  -
33 Repair the short to ground in the fuel injector command circuit. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 - Go to Step 39  -
34 Repair the short to ground in the injector supply voltage circuit. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 - Go to Step 39  -
35 Repair the open in the injector supply voltage circuit. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 - Go to Step 39  -
36 Replace the harness between the fuel injector and the multi-way connector.
Did you complete the replacement?		 - Go to Step 39  -
37
IMPORTANT: Refer to Engine Controls Component Views for fuel injector locations.
Replace the appropriate fuel injector. Refer to Fuel Injector Replacement .Did you complete the replacement?		 - Go to Step 39  -
38 Replace the FICM. Refer to Fuel Injection Control Module Replacement .
Did you complete the replacement?		 - Go to Step 39  -
39
  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 40 
40 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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