Turn ignition on. Backprobing at ECM, measure voltage between ground and ECM connector E61 terminal No. 17 (Yellow/Black wire). See Fig 1 . With A/C and blower switch Off, voltage should be 10-14 volts. With A/C and blower switch On, voltage should be 0-1.5 volts. If voltage readings are as specified, go to next step. If voltage readings are not as specified, check for open or short in Yellow/Black wire between ECM and A/C control module. See WIRING DIAGRAMS article. If no problem with wiring is found, check for A/C malfunction. See appropriate MANUAL or AUTOMATIC A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING.
Turn ignition on. Backprobing at ECM, measure voltage between ground and ECM connector E61 terminal No. 8 (Grey/White wire). With A/C and blower switch Off, voltage should be 0-1 volts. With A/C and blower switch On, voltage should be 10-14 volts. If voltage readings are as specified, A/C circuit s are okay. If voltage readings are not as specified, go to next step.
Check for open or short in Grey/White or Grey/Yellow wire between A/C amplifier and ECM. See Fig 1 . Also, check for poor performance of ECT sensor, TP sensor, engine start signal input to ECM. For testing procedures, see appropriate DTC testing procedure in SELF-DIAGNOSTICS - VITARA 2.0L . If problem is found, repair as necessary. After repair, retest system. If no problem with wiring or sensors is found, substitute ECM with known good unit and retest system.

Fig 1: A/C Signal Circuit Diagram (Vitara 2.0L)

Courtesy of SUZUKI OF AMERICA CORP.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

Vitara (2.0L)