Dtc P1638: Immobilizer Information Mismatched - Suzuki 2006 SX4 Service Manual

10C-15 Immobilizer Control System:
Step
5 Replacement of BCM
1) Replace BCM with new one referring to "BCM (Included
in Junction Block) Removal and Installation in Section
10B".
2) Check ECM for DTC referring to "DTC Check".
Is DTC P1636 still detected?

DTC P1638: Immobilizer Information Mismatched

Wiring Diagram
Refer to "Immobilizer Control System Wiring Circuit Diagram".
Detecting Condition and Trouble Area
Detecting Condition
• The immobilizer control system information in ECM and
the one in BCM does not match.
• The registration of the immobilizer control system
information in ECM is failed.
Troubleshooting
Step
1 Was "Immobilizer Control System Check" performed?
2 DTC confirmation
1) Disconnect negative (–) cable from battery for more than
5 seconds.
2) Connect negative (–) cable to battery.
3) Check if any DTC is detected referring to "DTC Check".
Is DTC P1638 still detected?
3 ECM specification check
1) Check ECM part number to see if ECM is applicable to
the vehicle in service.
Is a correct ECM used for the vehicle in service?
4 DTC check of ECM
1) Check ECM for DTC referring to "DTC Check in Section
1A".
Is DTC U0073, U0101, U0121 and/or U0140 detected?
5 DTC check of BCM
1) Check BCM for DTC referring to "DTC Check in Section
10B".
Is DTC U0073, U0100, U0101, U0155 and/or U1144
detected?
Action
Action
Yes
Substitute a known-
good ECM and recheck.
Trouble Area
• Use of the wrong ECM
• CAN communication circuit
• Keyless start control module (if equipped)
• Combination meter
• TCM (A/T model)
• 4WD control module (if equipped)
• ABS control module
• BCM
• ECM
Yes
Go to Step 2.
Go to Step 3.
Go to Step 4.
Go to applicable DTC
diag. flow.
Go to applicable DTC
diag. flow.
No
BCM faulty.
S6RW0CA304017
No
Go to "Immobilizer
Control System Check".
Intermittent trouble.
Check for intermittent
referring to "Intermittent
and Poor Connection
Inspection in Section
00".
Replace ECM with the
correct one and recheck
if DTC P1638 is still
detected by ECM.
Go to Step 5.
Go to Step 6.