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 MANUALSCHEVROLET2002AVALANCHE 2500, RWDREPAIR AND DIAGNOSIS (SINGLE PAGE)BODY & FRAMEDOOR LOCKSTHEFT DETERRENT SYSTEMDIAGNOSTIC INFORMATION AND PROCEDURESDTC P1626TEST DESCRIPTION
2002 Chevrolet Avalanche 2500, RWD
Test Description
2002 Chevrolet Avalanche 2500, RWDSECTION Test Description
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 body control module (BCM). If the scan tool cannot communicate with the BCM, refer to Diagnostic System Check - Theft Deterrent in Theft Deterrent.
- 3: This test checks for any opens in the serial data circuit between the powertrain control module (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, automatic temperature control (ATC), and body control module (BCM).
DTC P1626 Loss of Serial Communication with VTD
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: DATA LINK CONNECTOR (DLC) SCHEMATICS | |||
| 1 | Did you perform the Vehicle Theft Deterrent Diagnostic System Check? | Go to Step 2 | Go to Diagnostic System Check - Theft Deterrent |
| 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 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 the applicable DTC table | Go to TESTING FOR INTERMITTENT 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 AND POOR CONNECTIONS
and CONNECTOR REPAIRS
. Did you find and correct the condition? |
Go to Step 7 | Go to Step 9 |
| 9 |
IMPORTANT:
When replacing the BCM refer to BODY CONTROL MODULE (BCM) PROGRAMMING/RPO CONFIGURATION
. Replace the body control module. Refer to BODY CONTROL MODULE REPLACEMENT
.Did you complete the replacement? |
Go to Step 7 | - |
RENDER: 1.0x
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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.