DTC Troubleshooting: P0546 (55)
DTC P0546:
 EGT Sensor 1 Circuit High Voltage
NOTE: Before you troubleshoot, record all freeze data and review the general troubleshooting information.
  1. Start the engine, and keep idling until the engine coolant temperature becomes 70 °C (158 °F).
  1. Test-drive under these conditions:
    • Engine coolant temperature (ECT SENSOR 1) above 70 °C (158 °F)
    • On flat route
    • Transmission in 2nd gear
    • Vehicle speed above 60 km/h (38 mph)
    • Drive about 30 seconds or more
  1. Monitor the OBD STATUS for DTC P0546 in the DTCs MENU with the HDS.
Does the screen indicate FAILED?
YES -
Go to Step 4 .
NO -
If the screen indicates PASSED, intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at EGT sensor 1 and the ECM. If the screen indicates NOT COMPLETED, go to Step 1 and recheck.
  1. Turn the ignition switch OFF.
  1. Disconnect the EGT sensor 1 2P connector.
  1. Connect EGT sensor 1 2P connector terminals No. 1 and No. 2 with a jumper wire.
  1. Turn the ignition switch ON (II).
  1. Check EXHAUST GAS TEMPERATURE (EGT) SENSOR 1 in the DATA LIST with the HDS.
Is about 4.95 V or more indicated?
YES -
Go to Step 9 .
NO -
Go to Step 15 .
  1. Turn the ignition switch OFF, and wait 2 minutes.
  1. Disconnect ECM connector No. 1 (96P).
  1. Check for continuity between ECM connector No. 1 terminals No. 58 and No. 87.
Is there continuity?
YES -
Go to Step 24 .
NO -
Go to Step 12 .
  1. Remove the jumper wire from EGT sensor 1.
  1. Connect EGT sensor 1 2P connector terminal No. 2 to body ground with a jumper wire.
  1. Check for continuity between ECM connector No. 1 terminal No. 87 and body ground.
Is there continuity?
YES -
Repair open in the wire between EGT sensor 1 and ECM connector No. 1 terminal No. 58, then go to Step 17 .
NO -
Repair open in the wire between EGT sensor 1 and ECM connector No. 1 terminal No. 87, then go to Step 17 .
  1. Turn the ignition switch OFF.
  1. Reconnect all connectors.
  1. Turn the ignition switch ON (II).
  1. Reset the ECM with the HDS.
  1. Start the engine, and keep idling until the engine coolant temperature becomes 70 °C (158 °F).
  1. Test-drive under these conditions:
    • Engine coolant temperature (ECT SENSOR 1) above 70 °C (158 °F)
    • On flat route
    • Transmission in 2nd gear
    • Vehicle speed above 60 km/h (38 mph)
    • Drive about 30 seconds or more
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0546 indicated?
YES -
Check for poor connections or loose terminals at EGT sensor 1 and the ECM, then go to Step 1 .
NO -
Go to Step 23 .
  1. Monitor the OBD STATUS for DTC P0546 in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES -
Troubleshooting is complete. If any other Temporary DTCs or DTCs were indicated in Step 22 go to the indicated DTC's troubleshooting.■
NO -
If the screen indicates FAILED, check for poor connections or loose terminals at EGT sensor 1 and the ECM, then go to Step 1 . If the screen indicates NOT COMPLETED, go to Step 20 .
  1. Reconnect all connectors.
  1. Update the ECM if it does not have the latest software, or substitute a known-good ECM.
  1. Start the engine, and keep idling until the engine coolant temperature becomes 70 °C (158 °F).
  1. Test-drive under these conditions:
    • Engine coolant temperature (ECT SENSOR 1) above 70 °C (158 °F)
    • On flat route
    • Transmission in 2nd gear
    • Vehicle speed above 60 km/h (38 mph)
    • Drive about 30 seconds or more
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0546 indicated?
YES -
Check for poor connections or loose terminals at EGT sensor 1 and the ECM. If the ECM was update, substitute a known-good ECM, then go to Step 26 . If the ECM was substituted go to Step 1 .
NO -
Go to Step 29 .
  1. Monitor the OBD STATUS for DTC P0546 in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES -
If the ECM was updated, troubleshooting is complete. If the ECM was substituted, replace the original ECM. If any other Temporary DTCs or DTCs were indicated in Step 22 go to the indicated DTC's troubleshooting.■
NO -
If the screen indicates FAILED, check for poor connections or loose terminals at EGT sensor 1 and the ECM. If the ECM was update, substitute a known-good ECM, then go to Step 26 . If the ECM was substituted go to Step 1 . If the screen indicates NOT COMPLETED, go to Step 26 .