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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1070 (Engine Controls Diagnosis - 6.6L (Lb7) (DTCS P0237 To P0611)) >> Diagnosis >> DTC P0380 (California RPO YF5, NE1) >> 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. 4:  This step will determine if DTC P0380 is a hard failure.
  2. 5:  This step will determine if there is a short to voltage on the signal circuit.
  3. 9:  This step will determine if there is ignition voltage at the glow plug relay.
  4. 11:  This step will determine if the glow plug control circuit and ECM are working properly.
  5. 12:  This step will determine if there is a short to voltage on the relay control circuit.
  6. 14:  This step will determine if the glow plugs or the glow plug harness is causing the DTC P0380.
DTC P0380 (California RPO YF5, NE1)

Step Action Values Yes No
1 Did you perform the Diagnostic System Check-Engine Controls? - Go to Step 2  -
2
IMPORTANT: If this DTC set after an ECM reflash.
  1. Connect a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. Observe the Glow Plug System Type parameter on the scan tool.
Does the scan tool display the Glow Plug System Type as California?		 - Go to Step 3  Go to DTC P0380 (Federal RPO FE9, NG1)  or DTC P0380 (California RPO YF5, NE1) 
3 Did DTC P0489, P0540, P2141, and P2144 also set? - Go to Step 16  Go to Step 4 
4 
  1. Connect a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. Use the scan tool in order to command the glow plugs ON and OFF.
  4. Observe the glow plug feedback parameter on the scan tool.
Does the scan tool display the glow plug feedback parameter is within the specified range?		 5.0-5.6 V Go to Step 8  Go to Step 5 
5  Does the scan tool display a glow plug voltage more than the specified value? 5.6 V Go to Step 22  Go to Step 6 
6 Does the scan tool display a glow plug voltage more than the specified value? 0.70 V Go to Step 11  Go to Step 7 
7
  1. Turn ON the ignition, with the engine OFF.
  2. Touch the battery feed stud on the glow plug relay with an unpowered test lamp connected to ground.
Does the test lamp illuminate?		 - Go to Step 9  Go to Step 25 
8 The DTC is intermittent. If no additional DTCs are stored, refer to Diagnostic Aids.
If any additional DTCs were stored, refer to those tables.
Were there any additional DTCs stored?		 - Go to Diagnostic Trouble Code (DTC) List Go to Diagnostic Aids
9 
  1. Disconnect the glow plug relay middle connector.
  2. Turn ON the ignition, with the engine OFF.
  3. With an unpowered test lamp connected to ground, probe the glow plug relay harness ignition feed circuit.
Does the test lamp illuminate?		 - Go to Step 10  Go to Step 17 
10
  1. Turn ON the ignition, with the engine OFF.
  2. Connect an unpowered test lamp to B+, probe the glow plug relay harness ground circuit.
Does the test lamp illuminate?		 - Go to Step 11  Go to Step 18 
11 
  1. Turn ON the ignition, with the engine OFF.
  2. Verify that the glow plug relay harness is disconnected.
  3. With an unpowered test lamp connected to ground, probe the glow plug relay control circuit at the glow plug relay harness connector.
  4. Use a scan tool in order to command the glow plugs ON and OFF.
Does the test lamp illuminate with the scan tool command ON?		 - Go to Step 13  Go to Step 12 
12  Does the test lamp illuminate all of the time? - Go to Step 24  Go to Step 19 
13
  1. Verify that the glow plug relay is still disconnected.
  2. Turn ON the ignition, with the engine OFF.
  3. Using the J 35616  Connector Test Adapter Kit, jumper the glow plug control circuit to the glow plug signal circuit scan tool.
  4. Use a scan tool in order to command the glow plugs ON.
  5. Observe the scan tool while the glow plugs are commanded ON.
Does the glow plug parameter voltage measure near the specified value?		 Battery Voltage Go to Step 14  Go to Step 21 
14 
  1. Turn OFF the ignition.
  2. Disconnect the right and left bank glow plug output circuit connectors at the glow plug relay.
  3. With an unpowered test lamp connected to B+, probe each circuit.
Does the test lamp illuminate for each circuit?		 - Go to Step 27  Go to Step 15 
15
  1. Turn OFF the ignition.
  2. Disconnect each glow plug connector at the glow plug that did not illuminate the test lamp.
  3. With an unpowered test lamp connected to B+, probe the terminal on the glow plug.
Does each glow plug illuminate the test lamp?		 - Go to Step 27  Go to Step 26 
16 Repair the open or short to ground between the fuel heater fuse and the supplied components.
Did you complete the repair?		 - Go to Step 30  -
17 Repair an open in the glow plug relay ignition 1 voltage circuit.
Did you complete the repair?		 - Go to Step 30  -
18 Repair the open circuit or poor connections in the glow plug relay harness ground circuit.
Did you complete the repair?		 - Go to Step 30  -
19 Inspect the glow plug relay control circuit for an open or short to ground and repair as necessary. Refer to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 30  Go to Step 20 
20 Inspect the glow plug relay control circuit for a proper connection at the ECM and replace the terminal if necessary. Refer to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 30  Go to Step 29 
21 Inspect the glow plug relay signal circuit for an open or short to ground and repair as necessary. Refer to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 30  Go to Step 28 
22 Inspect the glow plug relay signal circuit for a proper connection at the ECM and replace the terminal if necessary.
Did you find an improper connection and make the necessary replacement?		 - Go to Step 30  Go to Step 23 
23 Inspect for a short to voltage in the glow plug relay signal circuit and repair as necessary. Refer to Wiring Repairs in Wiring Systems.
Did you find the improper condition?		 - Go to Step 30  Go to Step 27 
24 Inspect for a short to voltage in the glow plug control circuit and repair as necessary. Refer to Wiring Repairs in Wiring Systems.
Did you find the improper condition?		 - Go to Step 30  Go to Step 29 
25 Repair the open or poor connection on the battery voltage circuit. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 - Go to Step 30  -
26 Replace any glow plug that did not illuminate the test lamp.
Did you complete the replacement?		 - Go to Step 30  -
27 Inspect for an open or poor connection in the glow plug harness. Refer to Wiring Repairs in Wiring Systems.
Did you find and correction the condition?		 - Go to Step 30  Go to Step 28 
28 Replace the glow plug relay. Refer to Glow Plug Relay Replacement (Federal Emissions) or Glow Plug Relay Replacement (California Emissions) .
Did you complete the replacement?		 - Go to Step 30  -
29 Replace the ECM. Refer to Engine Control Module (ECM) Replacement .
Did you complete the replacement?		 - Go to Step 30  -
30
  1. Use the scan tool in order to clear the DTCs.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
Does the DTC run and pass?		 - Go to Step 31  Go to Step 1 
31 With a scan tool, observe the stored information, Capture Info.
Does the scan tool display any DTCs that you have not diagnosed?		 - Go to Diagnostic Trouble Code (DTC) List System OK
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