DTC 78-1: VTM-4 Control Unit

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2014 Honda Ridgeline, 2013 Honda Ridgeline, 2012 Honda Ridgeline, 2011 Honda Ridgeline, and 2010 Honda Ridgeline. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Before you troubleshoot, review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION ).

Turn the ignition switch to ON (II).
Clear the DTC with the HDS.
Test-drive the vehicle, and check for DTCs with the HDS.
Is DTC 78-1 indicated?

YES -Go to step 4.

NO -Intermittent failure, the system is OK at this time. ■
Check the battery (see BATTERY TEST ).
Is the specified battery installed, and is it fully charged?

YES -Go to step 5.

NO -Replace or charge the battery (see BATTERY REMOVAL AND INSTALLATION ). ■
Check the charging system indicator.
Does the charging system indicator come on with the ignition switch ON (II), and go off with the engine started?

YES -Go to step 6.

NO -Do the charging system troubleshooting (see CHARGING SYSTEM INDICATOR CIRCUIT TROUBLESHOOTING ). ■
Check for installation of any aftermarket CB or Ham radios which may cause an RF signal interference.
Is there an aftermarket radio installed?

YES -Disconnect the aftermarket radio, and retest. ■

NO -Check for poor connections or loose terminals at the VTM-4 control unit connectors. If the connections are OK, substitute a known-good VTM-4 control unit (see VTM-4 CONTROL UNIT REPLACEMENT ) and recheck. If the symptom/indication goes away with the known-good VTM-4 control unit, replace the original VTM-4 control unit (see VTM-4 CONTROL UNIT REPLACEMENT ). ■