DTC Troubleshooting: P0646 (128-6)

DTC P0646: A/C Clutch Relay Circuit Shorted to Ground Turn the ignition switch ON (II). Clear the DTC with the HDS. Do the A/C CLUTCH ON/OFF in the INSPECTION MENU with the HDS. Check for Temporary DTCs or DTCs with the HDS. Is DTC P0646 indicated?
YES | - | Go to Step 5 .
NO | - | Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the A/C clutch relay and the ECM.■
Turn the ignition switch OFF, and wait 30 seconds. Disconnect the A/C clutch relay in the under-hood fuse/relay box. Disconnect ECM connector No. 2 (58P). Check for continuity between ECM connector No. 2 terminal No. 45 and body ground. Is there continuity?
YES | - | Repair short in the wire between the A/C clutch relay and ECM connector No. 2 terminal No. 45, then go to Step 9 .
NO | - | Go to Step 14 .
Reconnect all connectors. Turn the ignition switch ON (II). Reset the ECM with the HDS. Do the A/C CLUTCH ON/OFF in the INSPECTION MENU with the HDS. Check for Temporary DTCs or DTCs with the HDS. Are any Temporary DTCs or DTCs indicated?
YES | - | If DTC P0646 is indicated, check for poor connections or loose terminals at the A/C clutch relay and the ECM, then go to Step 1 . If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.
NO | - | Troubleshooting is complete.■
Update the ECM if it does not have the latest software, or substitute a known-good ECM. Do the A/C CLUTCH ON/OFF in the INSPECTION MENU with the HDS. Check for Temporary DTCs or DTCs with the HDS. Are any Temporary DTCs or DTCs indicated?
YES | - | If DTC P0646 is indicated, check for poor connections or loose terminals at the A/C clutch relay and the ECM, then go to Step 1 . If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.
NO | - | If the ECM was updated, troubleshooting is complete. If the ECM was substituted, replace the original ECM. ■