Dtc P1618: Keyless Start Control Module Can Communication Error; Dtc P1621: Immobilizer Communication Line Error - Suzuki SX4 Service Manual

10C-13 Immobilizer Control System:

DTC P1618: Keyless Start Control Module CAN Communication Error

Refer to "Troubleshooting for CAN-DTC in Section 1A".

DTC P1621: Immobilizer Communication Line Error

Wiring Diagram
Refer to "Immobilizer Control System Wiring Circuit Diagram".
Detecting Condition and Trouble Area
Detecting Condition
Communication error between ICM and ECM.
Troubleshooting
Step
1 Was "Immobilizer Control System Check" performed?
2 Fuse check
1) Check fuse for ICM circuit.
Is fuse in good condition?
3 Voltage check at power and ground terminal
1) Check power and ground terminal voltage of ICM
connector referring to "Inspection of ICM and Its Circuit".
Is each terminal voltage in good condition?
4 ICM and ECM connector check
1) With the ignition switch at OFF position, check
intermittent and poor connection of ICM connector and
ECM connectors referring to "Intermittent and Poor
Connection Inspection in Section 00".
Is each connector in good condition?
5 Communication circuit check between ICM and ECM
1) Check for open, short and high resistance in serial
communication and clock circuit between ICM and ECM.
Is each communication circuit in good condition?
Action
Trouble Area
• Related fuse(s) blown
• Poor connection at ICM connector
• Poor connection at ECM connector
• Power supply circuit
• Ground circuit
• Communication circuits between ICM and ECM
• ICM
• ECM
Yes
Go to Step 2.
Replace blown fuse(s)
and then, check for
short circuit.
Go to Step 4.
Go to Step 5.
Substitute a known-
good ICM and recheck.
If DTC P1621 is still
detected, substitute a
known good ECM and
recheck.
S7RW0AA304011
S7RW0AA304012
No
Go to "Immobilizer
Control System Check".
Go to Step 3.
Repair circuit.
Repair poor connection.
Repair circuit.