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DTC P100A

DTC P100A:  Electric VTC Motor Circuit Malfunction

General Description 

GHH416798Courtesy of HONDA, U.S.A., INC.

The EVTM line of the powertrain control module (PCM) is installed to receive a diagnostic signal from the electric VTC motor. When the electric VTC relay is on under normal conditions, the EVTM line output from the electric VTC motor is 80 % (+/-5 %) duty. The PCM detects a malfunction and stores a DTC when the EVTM line output is anything other than 80 % (+/-5 %) duty continuously for the prescribed time or when though the electric VTC relay is turned on.

Monitor Execution, Sequence, Duration, DTC Type 

Execution Continuous
Sequence None
Duration 5 seconds or more
DTC Type One drive cycle, MIL on

Enable Conditions 

Condition Minimum Maximum
12 volt battery voltage [Battery] 10.5 V -

[ ]: HDS Parameter

Malfunction Threshold 

When the EVTM output pulse number is incorrect and the 80 % (+/-5 %) duty continuously for 5 seconds or more when the PCM has turned on the electric VTC relay.

Possible Cause 

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
  • Electric VTC motor EVTP line open
  • Electric VTC motor EVTM line open
  • Electric VTC motor GND line open
  • Electric VTC motor EVTP line short
  • Electric VTC motor EVTM line short
  • Electric VTC motor GND line short
  • Electric VTC motor VB1 (EVTC) line short to ground
  • Electric VTC motor VB2 (EVTC) line short to ground
  • Electric VTC motor VB2 (EVTC) line open
  • Electric VTC relay EVTC RLY CL- line open
  • Electric VTC relay EVTC RLY CL- line short to power
  • Electric VTC relay stuck off

Confirmation Procedure 

Operating Condition 

Turn the vehicle to the ON mode.

With the HDS 

Do the VTC TEST in the INSPECTION MENU with the HDS.

Diagnosis Details 

Conditions for setting the DTC 

When a malfunction is detected, the MIL comes on and a Pending DTC, a Confirmed DTC, and the freeze data are stored in the PCM memory.

Conditions for clearing the DTC 

The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command.