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Diagnostic Aids

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.
DTC P0103

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. Start the engine.
  2. Monitor the Diagnostic Trouble Code (DTC) Information using the scan tool.
Does the scan tool display any other DTCs set?		 - Go to Diagnostic Trouble Code (DTC) List 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 Diagnostic Aids
4
  1. Start the engine and allow the engine to idle.
  2. Observe the MAF Sensor parameter with a scan tool.
  3. Move the harness and the connector of the MAF sensor.
Does the movement of the harness or the connector affect the MAF Sensor parameter?		 - Go to Step 13  Go to Step 5 
5
  1. Observe the MAF Sensor parameter with a scan tool.
  2. Disconnect the harness connector of the MAF sensor.
Is the MAF Sensor parameter more than the specified value?		 444 g/s Go to Step 8  Go to Step 6 
6
  1. Turn OFF the engine.
  2. Turn ON the ignition, with the engine OFF.
  3. Connect a test lamp between the ignition 1 voltage circuit of the MAF sensor and the low reference circuit of the MAF sensor.
Does the test lamp illuminate?		 - Go to Step 14  Go to Step 7 
7
  1. Disconnect the ECM.
  2. Test the low reference circuit between the ECM and the MAF sensor for a high resistance or an open. Refer to Testing for Continuity in Wiring Systems.
Does the DMM indicate good continuity?		 - Go to Step 15  Go to Step 10 
8
IMPORTANT: Disconnecting the harness connectors of the ECM may eliminate the short to voltage if the signal circuit is shorted to another ECM circuit.
  1. Turn OFF the ignition.
  2. Disconnect the harness connectors of the ECM.
  3. Turn ON the ignition, with the engine OFF.
  4. Test the signal circuit of the MAF sensor for a short to voltage. Refer to Testing for a Short to Voltage in Wiring Systems.
Does the DMM indicate a short to voltage?		 - Go to Step 11  Go to Step 9 
9 Test for continuity at the harness connector of the ECM from the signal circuit of the MAF sensor to all other circuits at both ECM connectors with a DMM. Refer to Circuit Testing in Wiring Systems.
Does the DMM indicate continuity between any other circuit?		 - Go to Step 12  Go to Step 15 
10 Repair the high resistance or an open in the low reference circuit of the MAF sensor. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 - Go to Step 18  -
11 Repair the short to voltage in the signal circuit of the MAF sensor. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 - Go to Step 18  -
12 Repair the circuits that are shorted together. Refer to Wiring Repairs in Wiring Systems
Did you complete the repair?		 - Go to Step 18  -
13 Repair the harness or the connections as necessary. Refer to Circuit Testing in Wiring Systems.
Did you complete the repair?		 - Go to Step 18  -
14 Inspect for poor connections at the harness connector of the MAF sensor. Refer to Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 18  Go to Step 16 
15 Inspect for poor connections at the harness connector of the ECM. Refer to Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 18  Go to Step 17 
16 Replace the MAF/IAT sensor. Refer to Mass Air Flow (MAF)/Intake Air Temperature (IAT) Sensor Replacement .
Did you complete the replacement?		 - Go to Step 18  -
17 Replace the ECM. Refer to Engine Control Module (ECM) Replacement .
Did you complete the replacement?		 - Go to Step 18  -
18
  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 19 
19 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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