35. DTC: P0646, A/C Compressor Relay Control Circuit Voltage Too Low (see Table 1-48) Table 1-48 36. DTC: P0647, A/C Compressor Relay Control Circuit Voltage Too High (see Table 1-49) Table 1-49 64 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#, 85# of the relay (power supply end) and the power supply negative pole. Is the voltage about 12V? Yes Go to step 4 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 short to ground 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 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#, 85# of the relay (power supply end) and the power supply negative pole. Is the voltage about 12V? Yes Go to step 4 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 short to power supply 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