Inspection Procedure 5
Inspection Procedure 5: The Screen is not Normal in the Navigation Mode.CAUTION: Before replacing the ECU, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.
Audio Visual Navigation Unit Communication Circuit:
COMMENTS ON TROUBLE SYMPTOM
There is a failure in the wiring harness between the combination meter and the audio visual navigation unit, the GPS antenna, the respective connector(s), the combination meter or the audio visual navigation unit.
PROBABLE CAUSES
- Malfunctions of GPS antenna
- Malfunctions of combination meter
- Malfunctions of audio visual navigation unit
- Damaged harness wires and connectors
DIAGNOSIS
Required Special Tools:
- MB991223: Harness Set
- MB992006: Extra Fine Probe
STEP 1. Confirmation in MMCS service mode
Check the items below in the MMCS service mode. Service Mode
- Perform "Network/Connect Line Check" in the MMCS service mode to check that the communication and wire connection with the GPS are in good condition.
- Perform "Vehicle Signal Check", and then check the status of the vehicle speed signal.
- Perform "Sensor Check", and then check the status of the vehicle speed sensor and the gyro sensor.
Q: Is the check result normal?
YES (OK for all) : Go to Step 7.
NO
NO
NO
STEP 2. Check the fit of the GPS antenna cable.
Check whether the GPS antenna cable is connected properly.
Q: Is the GPS antenna cable connected properly?
YES : The trouble can be an intermittent malfunction (Refer to general (Body and Chassis), How to use Troubleshooting/inspection Service Points, How to Cope with Intermittent Malfunction).
NO : Go to Step 3.
STEP 3. Substitute a known good GPS antenna, and then check whether it works normally.
Q: Is the check result normal?
YES : Replace the GPS antenna.
NO : Go to Step 7.
STEP 4. Check the speedometer.
Check whether the speedometer works normally.
Q: Does the speedometer work normally?
YES : Go to Step 5.
NO : Diagnose the combination meter (Refer to Diagnosis). Symptom Chart
STEP 5. Check combination meter connector C-04 and audio visual navigation unit connector C-14 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q: Is combination meter connector C-04 and audio visual navigation unit connector C-14 in good condition?
YES : Go to Step 6.
NO : Repair or replace the damaged component (Refer to general (electrical) Harness Connector Inspection).
STEP 6. Check the wiring harness between combination meter connector C-04 (terminal 20) and audio visual navigation unit connector C-14 (terminal 13).
- Check the communication lines for open circuit.
NOTE: Also check joint connector C-03 and intermediate connector C-105 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If joint connector C-03 or intermediate connector C-105 is damaged, repair or replace the connector as described in general (electrical), Harness Connector Inspection.
Q: Is the wiring harness between combination meter connector C-04 (terminal 20) and audio visual navigation unit connector C-14 (terminal 13) in good condition?
YES : Go to Step 7.
NO : The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary.
STEP 7. Substitute a known good audio visual navigation unit, and check the trouble symptom.
Check whether the navigation screen is normal.
Q: Is the navigation screen normal?
YES : Replace the audio visual navigation unit.
NO : Replace the combination meter.