Test Description

The number(s) below refer to step(s) on the diagnostic table.

1. (1) The On-Board Diagnostic (OBD II) System Check prompts the technician to complete some basic checks and store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. The information is then stored on the scan tool for later reference.
2. (2) A Problem that may prevent the compressor from engaging may or may not cause DTC P0645 to set.
3. (3) If the scan tool indicates that the A/C request is ON, then the status circuit is OK.
4. (4) Using Freeze Frame and/or Failure Records data may aid in locating an intermittent condition. If the DTC cannot be duplicated, the information included in the Freeze Frame and/or Failure Records data can be useful in determining how many miles since the DTC set. The Fail Counter and Pass Counter can also be used to determine how many ignition cycles the diagnostic reported a pass and/or a fail. Operate vehicle within the same freeze frame conditions (rpm, load, vehicle speed, temperature, etc.) that were noted. This will isolate when the DTC failed.
5. (5) Checks whether ignition voltage is available at the relay.
6. (6) Determines if the A/C relay is at fault or the A/C request circuit is at fault. If the A/C clutch engages, this indicates that the A/C status circuit is OK.
7. (10) The replacement ECM must be reprogrammed. Refer to the latest Techline procedure for ECM reprogramming.

Fig 1: DTC P0645 - A/C Clutch Output Circuit Fault Chart (1 Of 2)

Courtesy of SUZUKI OF AMERICA CORP.

Fig 2: DTC P0645 - A/C Clutch Output Circuit Fault Chart (2 Of 2)

Courtesy of SUZUKI OF AMERICA CORP.