Toyota Sienna Service Manual: Vehicle Speed Signal Circuit between Radio and Navigation Assembly and Combination Meter
DESCRIPTION The radio and navigation assembly receives a vehicle speed signal from the combination meter and information about the GPS antenna, and then adjusts vehicle position.
HINT:
- A voltage of 12 V or 5 V is output from each ECU and then input to the combination meter. The signal is changed to a pulse signal at the transistor in the combination meter. Each ECU controls the respective system based on the pulse signal.
- If a short occurs in an ECU, all systems in the diagram below will not operate normally.
WIRING DIAGRAM
INSPECTION PROCEDURE
1 CHECK OPERATION OF SPEEDOMETER
- Drive the vehicle and check if the function of the speedometer on the combination meter is normal.
OK: Actual vehicle speed and the speed indicated on the speedometer are the same
HINT: The vehicle speed sensor is functioning normally when the indication on the speedometer is normal.
2 INSPECT RADIO AND NAVIGATION ASSEMBLY
- Disconnect the radio and navigation assembly connector R12.
- Measure the voltage.
- Jack up either one of the drive wheels.
- Move the shift lever to the neutral position.
- Turn the ignition switch to the ON position
- Measure the voltage between terminal SPD of the radio and navigation assembly and body ground when the drive wheels are turned slowly.
OK: Voltage pulses as shown in the illustration.
3 CHECK HARNESS AND CONNECTOR (COMBINATION METER - RADIO AND NAVIGATION ASSEMBLY)
- Disconnect the radio and navigation assembly connector R12 and combination meter connector C10.
- Measure the resistance according to the value(s) in the table below.
Standard resistance
4 CHECK HARNESS AND CONNECTOR (COMBINATION METER - RADIO AND NAVIGATION ASSEMBLY)
- Disconnect the radio and navigation assembly connector R12 and combination meter connector C10.
- Measure the resistance according to the value(s) in the table below.
Standard resistance
HINT: If the resistance between terminal SPD and body ground is less than 10 kΩ, there may be a short in a wire harness, connector, or an ECU.
REPLACE COMBINATION METER
Black Screen
INSPECTION PROCEDURE
1 CHECK DISPLAY SETTING
Check that the display is not in "Screen OFF" mode.
OK:
The display setting is not in "Screen OFF" mode.
2 CHECK IMAGE QUALIT ...
Steering Pad Switch Circuit
DESCRIPTION
This circuit sends an operation signal from the steering pad switch to the
radio receiver.
If there is an open in the circuit, the navigation system cannot be operated
using the st ...
Other materials:
Open in Occupant Classification ECU Battery
Positive Line
DTC B1794 Open in Occupant Classification ECU Battery
Positive Line
DESCRIPTION
This circuit consists of the occupant classification ECU and the power source
circuit (battery, fuse, wire
harness).
DTC B1794 is recorded when a malfunction is detected in the occupant
classification ECU or t ...
Definition of terms
Terms
Definitions
Monitor Description
Description of what ECM monitors and how to detect malfunctions
(monitoring purpose and details).
Related DTCs
A group of diagnostic trouble codes that are output by ECM based on
the same malfunction detection lo ...
Pressing Power Switch does not Turn on System
INSPECTION PROCEDURE
1 CHECK CABIN
Check that conditions in the cabin are not likely to cause
condensation.
HINT:
This problem occurs when the cabin is humid and the
temperature rapidly changes. This condition may
produce condensation, resulting in a short circuit.
OK:
Condensation ...
