32. DTC: P0601, Electronic Control Unit Check Code Unprogrammed (see Table 1-45) Table 1-45 33. DTC: P0602, Electronic Control Unit Diagnostic Data Identification Code Unprogrammed (see Table 1-46) Table 1-46 34. DTC: P0645, A/C Compressor Relay Control Circuit Trouble (see Table 1-47) Table 1-47 63 S/N Operation Test Results Actions 1 Connect the diagnostic instrument and adapter, and turn the ignition switch to ON. Next step 2 Clear the DTC, and check once again if the trouble is stable. Yes Next step No Normal 3 Replace ECU. End S/N Operation Test Results Actions 1 Connect the diagnostic instrument and adapter, and turn the ignition switch to ON.
Next step 2 Clear the DTC, and check once again if the trouble is stable. Yes Next step No Normal 3 Replace the ECU. End S/N Operation Test Results Actions 1 Connect the diagnostic instrument and adapter, and turn the ignition switch to OFF. Next step 2 Disconnect the A/C compressor relay, and turn the ignition switch to ON. Measure the voltage between pin 30#, 86# of the relay (power supply end) and the power supply negative pole. Is the voltage about 12V? Yes 4 Go to step No Next step 3 Check for open circuit or short to ground at the power supply end of the relay.
Yes Repair or replace harness No Go to step 2 4 Measure the voltage between the pin 86# of the relay (control end) and the power supply negative pole with a multimeter. Is the voltage about 3.7V? Yes Replace relay No Next step 5 Check for open circuit between the pin 86# of the relay (control end) and the 70# of the ECU with a multimeter. Yes Repair or replace harness No Diagnosis help