Without Scan Tool
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 VSA indicator may also come on. There are two methods used to check for DTCs. One method is to use the HDS 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 HDS. When the 16P DLC is connected to the HDS, 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.
Service Check Signal Circuit (SCS) Method
1. Park the vehicle on level ground. Shift to P, then turn off the engine.
2. Release the parking brake pedal.
3. With the ignition switch OFF, connect the HDS to the 16P DLC (A) located behind the driver's dashboard lower cover.
4. Short the SCS circuit to body ground using the HDS.
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.
6. Record all the DTC(s), then refer to the DTC Troubleshooting to determine the meaning of each DTC.
7. Clear the DTCs from the VTM-4 control unit memory.
8. If the MIL, D5 indicator, or the VSA indicator all come on at the same time, troubleshoot the cause for the MIL first then A/T DTCs second, then VSA third, and then VTM-4 last.
9. Test-drive the vehicle for several minutes in 4WD mode, and check for DTCs. If the DTC returns, refer to the DTC Troubleshooting. 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.