Lexus RX300 (MCU15). Service manual — part 388

DI–782

–

DIAGNOSTICS

LEXUS NAVIGATION SYSTEM

LEXUS RX300 (RM785E)

5

Navigation check mode (vehicle signal check mode: SPD).

NG

Replace or repair speed sensor wire harness.

OK

6

Is there anything such as a film stuck to the window or any metal object on the
instrument panel?

Yes

Reception may be affected by a screen such as
a film.

No

7

Recurrence Test (Confirm the phenomenon) (Correct the current position and
drive the vehicle for a while with the GPS mark displayed).

OK

Normal.

NG

Replace the navigation ECU.

8

Check if the harness is caught or sharply bent or not.

NG

Navigation antenna is surely connected.

OK

–

DIAGNOSTICS

LEXUS NAVIGATION SYSTEM

DI–783

LEXUS RX300 (RM785E)

9

Check optional components. (Does it become if the optionals such as the theft
deterrent system is removed?)

Yes

Remove or change the position of the compo-
nents.

HINT:
Some optionals receive radio signals, and if this happens, GPS
reception may be affected.

No

10

Service check mode. (Is ”80–40, 41” is displayed in the unit check mode of the
navigation ECU?)

Yes

Troubleshoot for each diagnosis.

No

Replace the navigation antenna.

HINT:
If the trouble still occurs, replace the navigation ECU.

DI–784

–

DIAGNOSTICS

LEXUS NAVIGATION SYSTEM

LEXUS RX300 (RM785E)

18. GPS mark does not appear.

INSPECTION PROCEDURE

1

Check the mark display. (At a place with a fine view, is GPS mark displayed or
not?)

Yes

Normal.

No

2

Is there anything such as a film stuck to the window or any metal object on the
instrument panel?

Yes

Reception may be affected by a screen such as
a film.

No

3

Check if the harness is caught or sharply bent or not.

NG

Navigation antenna is surely connected.

OK

DI7PB–03

–

DIAGNOSTICS

LEXUS NAVIGATION SYSTEM

DI–785

LEXUS RX300 (RM785E)

4

Check optional components. (Does it become normal if the optionals such as the
theft deterrent system is removed?)

Yes

Remove or change the position of the compo-
nents.

HINT:
Some optionals receive radio signals, and if this happens, GPS
reception may be affected.

No

5

Service check mode. (Is ”80–40, 41” is displayed in the unit check mode of the
navigation ECU?)

Yes

Troubleshoot for each diagnosis.

No

Replace the navigation antenna.

HINT:
If the trouble still occurs, replace the navigation ECU.