DTC U0028:87 [ADVANCED KEYLESS ENTRY AND PUSH BUTTON START SYSTEM]

id09021c399500

DESCRIPTION

Communication error with BCM
DETECTION CONDITION
•  Keyless control module receives the erratic signal from BCM.
•  Keyless control module cannot receive the signal from BCM.
POSSIBLE CAUSE
•  BCM DTC is stored
•  BCM connector or terminals malfunction
•  Keyless control module connector or terminals malfunction
•  Short to ground in wiring harness between the following terminals:
―  BCM terminal 4K—Keyless control module terminal 3X
•  Short to power supply in wiring harness between the following terminals:
―  BCM terminal 4K—Keyless control module terminal 3X
•  Open circuit in wiring harness between the following terminals:
―  BCM terminal 4K—Keyless control module terminal 3X
•  BCM malfunction
•  Keyless control module malfunction

Diagnostic Procedure

Step

Inspection

Action
1
CONFIRM BCM DTC
•  Perform the BCM DTC inspection using the M-MDS.
•  Are any DTCs present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [BCM].)
No
Go to the next step.
2
INSPECT BCM CONNECTOR AND TERMINALS
•  Switch the ignition to off.
•  Disconnect the negative battery cable.
•  Disconnect the BCM connector.
•  Inspect the connector and terminals (corrosion, damage, pin disconnection).
•  Is there any malfunction?
Yes
Repair or replace the connector or terminals, then go to Step 8.
No
Go to the next step.
3
INSPECT KEYLESS CONTROL MODULE CONNECTOR AND TERMINALS
•  Disconnect the keyless control module connector.
•  Inspect the connector and terminals (corrosion, damage, pin disconnection).
•  Is there any malfunction?
Yes
Repair or replace the connector or terminals, then go to Step 8.
No
Go to the next step.
4
INSPECT COMMUNICATION CIRCUIT FOR SHORT TO GROUND
•  BCM and keyless control module connectors are disconnected.
•  Inspect for continuity between the following terminal (wiring harness-side) and body ground:
―  BCM terminal 4K
•  Is there continuity?
Yes
Repair or replace the wiring harness for a possible short to ground, then go to Step 8.
No
Go to the next step.
5
INSPECT COMMUNICATION CIRCUIT FOR SHORT TO POWER SUPPLY
•  BCM and keyless control module connectors are disconnected.
•  Reconnect the negative battery cable.
•  Switch the ignition to ON.
•  Measure the voltage at the following terminal (wiring harness-side):
―  BCM terminal 4K
•  Is there any voltage?
Yes
Repair or replace the wiring harness for a possible short to power supply, then go to Step 8.
No
Go to the next step.
6
INSPECT COMMUNICATION CIRCUIT FOR OPEN CIRCUIT
•  BCM and keyless control module connectors are disconnected.
•  Switch the ignition to off.
•  Disconnect the negative battery cable.
•  Inspect for continuity between the following terminals (wiring harness-side):
―  BCM terminal 4K—Keyless control module terminal 3X
•  Is there continuity?
Yes
Go to the next step.
No
Repair or replace the wiring harness for a possible open circuit, then go to Step 8.
7
VERIFY BCM MALFUNCTION
•  Make sure to reconnect the disconnected connectors.
•  Reconnect the negative battery cable.
•  Operate the advanced key to activate the keyless control module.
•  Clear the DTC from the keyless control module using the M-MDS.
•  Operate the advanced key to activate the keyless control module.
•  Perform the advanced keyless entry and push button start system DTC inspection using the M-MDS.
•  Is the same DTC present?
Yes
Replace the BCM, then go to the next step.
(See BODY CONTROL MODULE (BCM) REMOVAL/INSTALLATION [L.H.D.].)
(See BODY CONTROL MODULE (BCM) REMOVAL/INSTALLATION [R.H.D.].)
No
Go to Step 9.
8
VERIFY TROUBLESHOOTING COMPLETED
•  Make sure to reconnect the disconnected connectors.
•  Reconnect the negative battery cable.
•  Operate the advanced key to activate the keyless control module.
•  Clear the DTC from the keyless control module using the M-MDS.
•  Operate the advanced key to activate the keyless control module.
•  Perform the advanced keyless entry and push button start system DTC inspection using the M-MDS.
•  Is the same DTC present?
Yes
Replace the keyless control module, then go to the next step.
(See KEYLESS CONTROL MODULE REMOVAL/INSTALLATION.)
No
Go to the next step.
9
VERIFY THAT NO OTHER DTCs ARE PRESENT
•  Are any DTCs present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [ADVANCED KEYLESS ENTRY AND PUSH BUTTON START SYSTEM].)
No
DTC troubleshooting completed.