For 1990-2009 cars
Body Control Module Components
Body Control System Schematics
Handling ESD Sensitive Parts Notice

### Circuit Description

When pressing any button on the keyless entry transmitter, the transmitter will send a radio frequency signal to the remote control door lock receiver (RCDLR).

The RCDLR interfaces with the body control module (BCM) in order to perform the door lock/unlock functions. On vehicles equipped with the content theft deterrent (BCM type 4), the RCDLR interfaces with the BCM in order to perform the alarm functions.

The RCDLR sends a digital message to the BCM through CKT 1455. The RCDLR determines the type of message sent to the BCM based on the button pressed on the keyless entry transmitter.

The BCM determines what functions to perform (door lock/unlock, alarm) based on the messages received from the RCDLR.

### Conditions for Setting the DTC

The BCM detects an open, a short to B+, or a short to ground in CKT 1455.

### Action Taken When the DTC Sets

• | The BCM sets the diagnostic trouble code (DTC) 8.

• | The keyless entry system remains inoperative. The rear compartment lid release may still be operational because the RCDLR operates the rear compartment lid directly without using the BCM.

### Conditions for Clearing the MIL/DTC

• | An open, a short to B+, or a short to ground in CKT 1455 is no longer present between the BCM and the RCDLR.

• | After the repairs are completed, refer to Clearing Diagnostic Trouble Codes in order to clear the DTC.

### Diagnostic Aids

• | Inspect for an open, a short to B+, or a short to ground in CKT 1455.

• | A faulty horn RCDLR.

• | Perform the following test while moving the wiring and connectors. This will cause the malfunction to appear.

#### BCM Input/Output Test Procedure

1. Turn the instrument panel dimmer switch to the OFF position.
2. Turn the ignition switch to the LOCK position.
3. Remove the BCM PRGRM fuse.
4. Turn the ignition switch to the ACC position.

The BCM will sound a chime the number of times equal to the BCM type installed on the vehicle.

5. Within one second turn the ignition switch from the ACC position to the LOCK position, then back to the ACC position.

The BCM will sound any DTCs that are stored.

6. Turn the instrument panel dimmer switch to the DOME position.

The BCM has entered the Input/Output Test. The BCM Input/Output includes the following tests:

• | Test 1 de-energizes CKT 1393 (protected courtesy lamp output).

• | Test 2 energizes CKT 1393.

• | Test 3 grounds CKT 690 (courtesy lamps control).

• | Test 4 energizes the theft deterrent relay for 1 second by grounding CKT 301, and turns on the headlamps (BCM type 3 and type 4 only).

• | Test 5 energizes the horn relay for 25 ms by grounding CKT 28, and sounds the horn (BCM type 4 only).

• | Test 6 turns on the theft deterrent indicator lamp by grounding CKT 749 (BCM type 4 only).

• | Test 7 turns off the theft deterrent indicator lamp by opening CKT 749 (BCM type 4 only).

The BCM operates the Input/Output test in numerical order.

In order to move to the next test, cycle the IP dimmer switch from the DOME position to the OFF position, then back to the DOME position. The BCM will sound a chime a number of times equal to the Input/Output test number above. The Input/Output test sequence repeats until the ignition switch is turned to the LOCK position.

When the BCM is performing the Input/Output test the BCM will sound the chime when any of the keyless remote transmitter buttons is pressed (BCM type 3 and type 4 only). This test inspects for and ensures that the BCM is receiving commands from the keyless entry transmitter via the RCDLR.

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. Always perform the BCM diagnostic system check before attempting to diagnose DTC 8.

2. This step determines whether the malfunction is related to a fault within the remote control door lock receiver (RCDLR) and not due to a faulty CKT 1455.

3. This steps determines whether the malfunction is intermittent and not currently present.

4. This step inspects for an open in CKT 1455.

5. This step inspects for a short to ground in CKT 1455.

6. This step inspects for a short to B+ in CKT 1455.

7. This step determines whether the malfunction is intermittent and not related to a faulty BCM.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the BCM diagnostic system check? | -- | Go to Step 2 | Go to Diagnostic System Check - Body Control System
2 |

1. If the vehicle is not equipped with the Power Sliding Door (PSD), go to Step 3 .
2. Disable the PSD lockout switch (released position).
3. Operate (open/close) the PSD by pressing the PSD button on the keyless entry transmitter.

Does the PSD operate through the keyless entry transmitter?

--

Go to Step 3

Go to Step 8

3 | Perform the BCM Input/Output test. Refer to Diagnostic Aids. Does the chime sound when pressing any button on the keyless entry transmitter when the BCM is in the Input/Output test? | -- | Go to Step 7 | Go to Step 4
4 |

1. Turn the ignition switch to the LOCK position.
2. Disconnect the BCM connector C2.
3. Disconnect the remote control door lock receiver (RCDLR).
4. Use a J 39200 digital multimeter (DMM) in order to measure the resistance between the BCM harness connector C2 terminal C8 and the RCDLR harness connector terminal E.

Is the resistance less than or equal to the specified value?

2ohms

Go to Step 5

Go to Step 9

5 | Use a J 39200 DMM in order to measure the resistance between the BCM harness connector C2 terminal C8 and ground. Is the resistance equal to the specified value? | Infinite | Go to Step 6 | Go to Step 10
6 |

1. Turn the ignition switch to the RUN position.
2. Use a J 39200 DMM in order to measure the voltage between the BCM harness connector C2 and terminal C8 and ground.

Is the voltage less than the specified value?

2V

Go to Step 7

Go to Step 11

7 |

1. Turn the ignition switch to the LOCK position.
2. Connect all of the connectors.
3. Install all of the components.
4. Turn the ignition switch to the RUN position.
5. Press any button on a keyless entry transmitter.
6. Turn the ignition switch to the LOCK position.
7. Remove the BCM PRGRM fuse.
8. Turn the ignition switch to the ACC position. The BCM sounds the chime a number of times equivalent to the BCM type installed on the vehicle.
9. Within 1 second, turn the ignition switch from the ACC position, to the LOCK position, then back to the ACC position. The BCM sounds any DTCs stored.

Does DTC 8 reset?

--

Go to Step 12

Go to Step 13

8 | The keyless entry system is inoperative. Refer to Remote Keyless Entry System Check Is the action complete? | -- | Go to Step 14 | --
9 | Repair the poor connection or open in CKT 1455. Is the repair complete? | -- | Go to Step 14 | --
10 | Repair short to ground in CKT 1455. Is the repair complete? | -- | Go to Step 14 | --
11 | Repair short to B+ in CKT 1455. Is the repair complete? | -- | Go to Step 14 | --
12 |

1. Inspect the BCM connector C2 terminal D8 for a short to B+. Repair the connector as needed.
2. If the connector is not faulty, replace the BCM. Refer to Body Control Module Replacement

Is the repair complete?

--

Go to Step 14

--

13 | The malfunction is not present at this time. Refer to Diagnostic Aids. Is the action complete? | -- | Go to Diagnostic System Check - Body Control System | --
14 |

1. Turn the ignition switch to the LOCK position.
2. Reinstall the connectors/components.
3. Remove the BCM PRGRM fuse.
4. Turn the ignition switch to the ACC position. The BCM sounds the chime a number of times equivalent to the BCM type installed on the vehicle.
5. Within 1 second, turn the ignition switch from the ACC position, to the LOCK position, then back to the ACC position. The BCM sounds any DTCs stored.

Are any BCM DTCs present?

--

Go to Diagnostic System Check - Body Control System

System OK