Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET2006CHEVY EXPRESS G2500, VAN CARGO, 6.6 2REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 945 (IMMOBILIZER SYSTEM)DIAGNOSTIC INFORMATION AND PROCEDURESDTC P1626TEST DESCRIPTION
2006 Chevrolet Chevy Express G2500, Van Cargo, 6.6 2
Test Description
2006 Chevrolet Chevy Express G2500, Van Cargo, 6.6 2SECTION Test Description
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2007 GMC Savana Special, 2007 GMC Savana Camper Special, 2007 GMC Savana, 2007 Chevrolet RV Cutaway, and 2007 Chevrolet Cutaway. 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.
- 2: This test checks if communications can be established between the scan tool and the BCM.
- 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.
- 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.
- 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: Data Communication 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.
IMPORTANT:
Do not start the vehicle.
|
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:
Did you find a problem? |
Go to Step 6 | Go to Step 4 |
| 4 |
|
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.
|
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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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.