GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2001 🢒 Seville - RHD 🢒 DTC 🢒 DTC B2220-B2224, or B2226

Circuit Description

The switch that failed and generated this diagnostic trouble code (DTC) is one of the rear door lock switches mounted locally, one in each rear door. The left rear door module (LRDM), and the right rear door module (RRDM) each contain a microprocessor which takes the signal generated by its switch and assigns a digital message to it. The LRDM, or RRDM then sends this message over the power door serial data communication line to the driver door module (DDM). The DDM sends this information over the Serial Data Class 2 line to the rear integration module (RIM), which is the master of all lock operations. If the RIM determines that the message is a valid request, it sends its OK back, via the Class 2 line to the DDM. The DDM then locks its own door and sends the message, via the power door serial data communication line, to the other door modules to lock their doors. Each door module supplies power and ground to its associated lock actuator to lock its door.

Conditions for Running the DTC

The door modules must be powered and can not have B1327-Battery Voltage Low or B1328-Battery Voltage High set for this DTC to set.

Conditions for Setting the DTC

If the DDM detects that the switch signal is active for more than 30 continuous seconds, it sets this DTC.

Action Taken When the DTC Sets

The module ignores inputs from the failed switch and prevents locking functions from it until the input is no longer received.

Conditions for Clearing the MIL/DTC

The DDM clears the DTC when the switch signal is no longer received.

Diagnostic Aids

A sticking or binding switch can cause the DTC to set.

Test Description

The number below refers to the step number on the diagnostic table.

  1. Checks the existing state of the applicable passenger door lock switch by using the state of the applicable door module Input parameter.

Step

Action

Yes

No

Schematic Reference: Door Lock/Indicator Schematics

1

Did you perform the Door Systems Diagnostic System Check?

Go to Step  2

Go to Diagnostic System Check - Door Systems

2

  1. Install a Scan tool.
  2. Turn ON the ignition with the engine OFF.
  3. With the scan tool, observe the appropriate Door Lock Sw. parameter in the Driver Door Module Inputs list.

Does the scan tool display Idle?

Go to Step  3

Go to Step  4

3
  1. Activate the applicable door lock switch.
  2. With the scan tool, observe the appropriate Door Lock Sw. parameter in the Driver Door Module, Inputs list.

Did the Door Lock Sw. Inputs parameter change state?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step  4

4
  1. Turn OFF the ignition.
  2. Disconnect the applicable door lock switch harness connector.
  3. Turn ON the ignition with the engine OFF.
  4. With the scan tool, observe the appropriate Door Lock Sw. parameter in the Driver Door Module Inputs list.

Does the scan tool indicate the Idle state?

Go to Step  7

Go to Step  5

5

Test the applicable passenger door lock switch Lock or Unlock signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step  10

Go to Step  6

6

Inspect for poor connections at the applicable door module harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step  10

Go to Step  8

7

Inspect for poor connections/terminal tension at the applicable door lock switch harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step  10

Go to Step  9

8

Replace the applicable door module. Refer to Door Control Module Replacement .

Did you complete the replacement?

Go to Step  10

--

9

Replace the applicable door lock switch. Refer to Door Lock Switch Replacement .

Did you complete the replacement?

Go to Step  10

--

10
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step  2

System OK