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Home >> Hummer >> 2008 >> H2 4D Utility Wagon >> Repair and Diagnosis >> External Pages >> Different car >> Section 50 (Immobilizer) >> Diagnostic Information and Procedures >> DTC P1626 >> Test Description

Test Description

WARNING: This page is about a different car, the 2007 Hummer H2. 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 test checks if communications can be established between the scan tool and the BCM.
  2. 3:  This test checks for any opens in the serial data circuit between the PCM and the BCM. This also checks for any intermittent malfunctions associated with the serial data circuit.
  3. 4:  This step is to determine if the condition that set the DTC is still present. The engine must be cranked in order to set this DTC. If the condition is present, the engine will start and then stall, indicating the PCM is disabling fuel.
  4. 7:  Use a scan tool to clear and check for any DTCs in all the modules connected to the class 2 serial data circuit, such as the PCM, BCM, and automatic temperature control (ATC).
DTC P1626

Step Action Yes No
Schematic Reference: Immobilizer Schematics 
1 Did you perform the Diagnostic System Check - Vehicle? Go to Step 2  Go to Diagnostic System Check - Vehicle
2 
IMPORTANT: You must diagnose the Bxxxx codes prior to diagnosing any Pxxxx code.
  1. Install a scan tool.
    2. IMPORTANT: Do not start the vehicle.
  2. Momentarily rotate the ignition switch to CRANK.
  3. Release the ignition switch to ON.
  4. Select the powertrain control module display DTCs function on the scan tool.
Does the scan tool display DTC P1626 as a current DTC?		 Go to Step 3  Go to Testing for Intermittent Conditions and Poor Connections
3  Check the class 2 serial data circuit for the following intermittent conditions:
  • An open in the class 2 serial data circuit between the powertrain control module (PCM) and the body control module (BCM)
  • A short to ground
  • A short to voltage
  • Loose or damaged terminals at the data link connector (DLC), PCM, or the BCM

Did you find a problem?		 Go to Step 6  Go to Step 4 
4 
  1. Turn OFF the ignition.
  2. Connect or install any connectors or components that were disconnected or removed.
  3. Clear all DTCs using a scan tool.
  4. Turn OFF the ignition for 15 seconds.
  5. Attempt to start the engine.
Does DTC P1626 reset?		 Go to Step 8  Go to Step 5 
5 This DTC is intermittent.
Are any additional DTCs stored?		 Go to Diagnostic Trouble Code (DTC) List - Vehicle Go to Testing for Intermittent Conditions and Poor Connections
6 Repair the circuit as necessary. Refer to Wiring Repairs or Connector Repairs .
Is the action complete?		 Go to Step 7  -
7 
IMPORTANT: Before clearing DTCs, monitor all DTC status parameters and note any additional DTCs.
  1. Turn OFF the ignition.
  2. Connect or install any connectors or components that were disconnected or removed.
  3. Clear all PCM DTCs using a scan tool.
  4. Turn OFF the ignition for 15 seconds.
  5. Start the engine and allow it to run.
Does the DTC reset?		 Go to Step 2  System OK
8 Inspect for poor connections at the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?		 Go to Step 7  Go to Step 9 
9 Replace the BCM. Refer to Control Module References for replacement, setup, and programming.
Did you complete the replacement?		 Go to Step 7  -
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