Suzuki Grand Vitara 2011 Manual page 246

1A-177 Engine General Information and Diagnosis: For Petrol Engine Model
DTC Detecting Condition
When ECM receives a trouble code from TCM, which indicates that some problem occurred in sensor circuits and its
calculated values used for operations such as idle speed control, engine power control, and so on by TCM, ECM sets
DTC P1603. (TCM outputs the trouble code to ECM when TCM can not compute the engine control signal due to
malfunctions of sensor circuits used for gear shift control.)
DTC Troubleshooting
NOTE
Before this trouble shooting is performed, read the precautions for DTC troubleshooting referring to
"Precautions for DTC Troubleshooting: For Petrol Engine Model".
Step
1 Was "Engine and Emission Control System Check"
performed?
2 DTC check
1) Check DTC of TCM referring to "DTC Check in Section
5A".
Is there any DTC(s)?
Action Yes
Go to Step 2.
Go to applicable DTC
diag. flow.
No
Go to "Engine and
Emission Control
System Check: For
Petrol Engine Model".
Substitute a known-
good ECM and recheck.