Reading Diagnostic Trouble Codes
How to Check for DTCsWhen the VTM-4 control unit senses an abnormality in the input or output systems, the VTM-4 indicator in the gauge assembly will usually come on, and the malfunction indicator lamp (MIL), the D5 indicator and/ or the ABS indicator may also come on. There are two methods used to check for DTCs. One method is to use the Honda PGM Tester with the appropriate software plugged into the 16P data link connector (DLC).
The other method is to connect the service check signal (SCS) circuit with the Honda PGM Tester. When the 16P DLC is connected to the Honda PGM Tester, the VTM-4 indicator will blink the diagnostic trouble code (DTC) when the ignition switch is turned ON (II) and the SCS circuit is connected to body ground.
Honda PGM Tester method:
1. With the ignition switch OFF, connect the Honda PGM Tester (A) to the 16P DLC (B) located behind the driver's dashboard lower cover.
2. Turn the ignition switch ON (II), and follow the prompts on the Honda PGM Tester to display the DTC(s) on the screen. After determining the DTC(s), refer to the DTC Troubleshooting Index.
NOTE: See the Honda PGM Tester user's manual for specific instruction.
3. If there are fuel and emissions DTCs, A/T DTCs, and ABS DTC's at the same time, troubleshoot the fuel and emission DTC's first.
4. After recording the DTCs, clear all DTCs.
5. Test-drive the vehicle for several minutes in 4WD mode, and check for DTCs. If the DTC returns, refer to the DTC Troubleshooting Index. If the DTC does not return, there was an intermittent problem within the circuit. Make sure all connectors and terminals in the circuit are tight.
Service Check Signal Circuit (SCS) Method:
1. Park the vehicle on level ground. Shift to the HI position, then turn off the engine.
2. Release the parking brake pedal.
3. With the ignition switch OFF, connect the Honda PGM Tester (A) to the 16P DLC (B) located behind the driver's dashboard lower cover.
4. Connect the SCS circuit to body ground using the Honda PGM Tester.
5. Turn the ignition switch ON (II), and observe the VTM-4 indicator.
NOTE: Codes above 10 are indicated by a series of long and short blinks. One long blink equals 10 short blinks. Add the long and short blinks together to determine the code. After determining the code, refer to the DTC Troubleshooting Index.
6. Record the all DTC(s), then refer to the DTC Troubleshooting Index to determine the meaning of the DTC.
7. Clear the DTCs from the VTM-4 control unit memory.
8. If the MIL, D5 indicator, and the ABS indicator all come on at the same time, troubleshooting the cause for the MIL first.
9. Test-drive the vehicle for several minutes in 4WD mode, and check for DTCs. If the DTC returns, refer to the DTC Troubleshooting Index. If the DTC does not return, there was an intermittent problem within the circuit. Make sure all connectors and terminals in the circuit are tight.