GM Service Manual Online
For 1990-2009 cars only

Object Number: 486286  Size: MF
Data Link Communications Components
Data Link Connector Schematics
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The SBI data line communicates information between the door modules. Each module connected to the SBI is assigned a recognition code, or address. This code is used in order to identify which modules are communicating. Modules communicate with each other by periodically sending state of health (SOH) messages. When the ignition switch is in RUN, each module communicating on the SBI sends an SOH message every 2 seconds. This ensures that the system is operating properly. When the rear door module (PDM) stops communicating on the SBI, the SOH messages that is normally sent on the SBI disappears. The driver door module (DDM) which expects to receive that message detects the absence of the message and sets DTC U1162.

Conditions for Running the DTC

  1. The DDM does not receive an SOH message back from the RDM.
  2. The DTC only sets if U1300 or U1301 are not current.

Action Taken When the DTC Sets

    • DTC U1162 is stored in the DDM.
    • The DDM uses the default values for the initialization data.
    • This DTC does not cause a driver warning message to appear.

Conditions for Clearing the DTC

    • This DTC clears (status changes from current to history) under any of the following conditions:
       - The DDM detects an SOH message from the PDM.
       - At each ignition cycle
    • A history DTC clears after 50 consecutive ignition cycles if the conditions for setting the DTC are no longer present.
    • Current and history DTCs may be cleared using a scan tool.

Diagnostic Aids

    • DTC module U1162 does not normally represent a failure within the module.
    • If the DTC is a history DTC, the condition may be intermittent.

DTC U1162 Loss of Rear Door Module SBI

Step

Action

Value(s)

Yes

No

1

Did you perform the Data Link Communications Diagnostic System Check?

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Go to Step 2

Go to Diagnostic System Check - Data Link Communications

2

Are DTCs U1162 and U1170 also current?

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Go to DTC U1170 Loss of Driver Door Switch SBI

Go to Step 3

3

Inspect for an open in CKT 217 (LT BLU) between connector C1 terminal 12 of the rear door module (RDM) and connector C2 terminal C10 of the rear junction block.

Did you find a condition?

--

Go to Step  4

Go to Power Windows System Check in Doors

4

Repair the open in CKT 217 (LT BLU).

Did you complete the repair?

--

Go to Step  5

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5

  1. Turn the ignition switch to OFF.
  2. Reconnect or install any connectors or components that were disconnected or removed.
  3. Turn the ignition switch to ON.
  4. Clear all DTCs.

Is the repair complete?

--

Go to Diagnostic System Check - Data Link Communications

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