DTC P1458: A/C Compressor Control Signal Malfunction: Procedure

Turn ignition on. Set A/C switch off and blower switch to No. 1 position. Backprobe and measure voltage between ECM harness connector terminal No. 64 (Gray/Red wire) and ground. See Figure . If voltage is about 5 volts, go to next step. If voltage is not about 5 volts, check for short to ground or short to power in wire between A/C switch terminal No. 2 (Green/Orange wire) and ECM terminal No. 64 (Gray/Red wire). See Figure . See wiring diagram in appropriate MANUAL A/C-HEATER SYSTEMS article. Also, check A/C switch for internal short. If problem exists, repair as necessary.
Turn A/C switch on. Backprobe and measure voltage between ECM harness connector terminal No. 64 (Gray/Red wire) and ground. If voltage does not exist, go to next step. If voltage exists, repair open in wire(s) or connector(s) between grounding junction connector No. 20 and ECM harness connector terminal No. 64. Check for open or short to battery in wire between A/C switch terminal No. 2 (Green/Orange wire) and ECM harness connector terminal No. 64 (Gray/Red wire). Repair wiring as necessary.
Turn A/C switch and blower switch off. Leave ignition on. Backprobe and measure voltage between ECM harness connector terminal No. 65 (Brown/Yellow wire) and ground. If voltage is about 5 volts, check for intermittent short between A/C thermostat harness connector terminal No. 2 (Black/Red wire) and ECM harness connector terminal No. 65 (Brown/Yellow wire). If problem exists, repair as necessary. If voltage is 8-9 volts, verify A/C switch is off. If A/C switch is on, turn A/C switch off and repeat step 3 . If A/C switch is off, check for shorted A/C switch. If problem exist, replace A/C switch. If voltage is about zero volts, check for shorted A/C thermostat. If problem exists, replace A/C thermostat. If problem does not exist, repair short to ground in wire between A/C thermostat terminal No. 2 and ECM harness connector terminal No. 65.