Speed Signal Circuit
METER / GAUGE / DISPLAY: METER / GAUGE SYSTEM: Speed Signal Circuit
- Speed Signal Circuit
DESCRIPTION
The combination meter receives the vehicle speed signal from this circuit. The wheel speed sensors produce an output that varies according to the vehicle speed. The wheel speed sensor output is received by the skid control ECU which uses this information to create the vehicle speed sensor signal*. The vehicle speed sensor signal consists of pulses sent to the combination meter from the skid control ECU. To create this signal, 12 V is output from IG2 which is behind a resistor in the combination meter. This voltage is sent to the skid control ECU. The pulse signal is created by switching the transistor in the skid control ECU on and off, making the voltage on the wire drop to 0 V. A similar system is used for the output of this signal from the combination meter via terminal +S. A voltage of 12 V or 5 V is applied to terminal +S from each ECU or relay that is connected to this terminal. The transistor in the combination meter is controlled by the signal from the skid control ECU. When this transistor is turned on, this transistor makes the voltage supplied by the various ECUs (via their respective internal resistors) drop to 0 V. Each ECU connected to terminal +S of the combination meter controls its respective system based on the pulse signal.
* *: This vehicle speed sensor signal is created by the skid control ECU. There is no actual component that is referred to as the vehicle speed sensor. In addition, for some other systems, vehicle speed information may be exchanged using CAN communication.
HINT
This circuit is used for the systems connected to terminal +S. This signal is not used for combination meter operation. Combination meter components such as the speedometer operate using data received via CAN communication.
WIRING DIAGRAM
1. except TMC Made 2ZR-FE
2. for TMC Made 2ZR-FE
3. except TMC Made 2AZ-FE
INSPECTION PROCEDURE
PROCEDURE
1. INSPECT ECU TERMINAL VOLTAGE (INPUT VOLTAGE)
(a) Disconnect the E46 connector.
(b) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
HINT
If any of the ECUs specified in the wiring diagram supplied power to the combination meter, the combination meter will output a waveform.
Result:
C -- CHECK HARNESS AND CONNECTOR
B -- CHECK HARNESS AND CONNECTOR (COMBINATION METER - NO. 4 JUNCTION BLOCK)
A -- Continue to next step.
2. INSPECT COMBINATION METER (OUTPUT VOLTAGE)
(a) Reconnect the E46 connector.
(b) Disconnect the A51*1 or A66*2 connector.
(c) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
* *1: w/o VSC
* *2: w/ VSC
NG -- CHECK HARNESS AND CONNECTOR (COMBINATION METER - SKID CONTROL ECU)
OK -- Continue to next step.
3. INSPECT SKID CONTROL ECU (INPUT WAVEFORM)
(a) Check the input waveform.
(1) Reconnect the A51*1 or A66*2 connector.
### ptxt ### *1: w/o VSC
### ptxt ### *2: w/ VSC
(2) Remove the combination meter with the connector(s) still connected.
(3) Connect the oscilloscope to terminals E46-35 (SI) and body ground.
(4) Turn the ignition switch to ON.
(5) Turn the wheel slowly.
(6) Check the signal waveform according to the condition(s) in the table below.
OK:
The waveform is displayed as shown in the illustration.
HINT
When the system is functioning normally, one wheel revolution generates 4 pulses. As the vehicle speed increases, the width indicated by (A) in the illustration narrows.
Result:
C -- REPLACE SKID CONTROL ECU (w/ VSC) Removal
B -- REPLACE SKID CONTROL ECU (w/o VSC) Removal
A -- REPLACE COMBINATION METER
4. CHECK HARNESS AND CONNECTOR (COMBINATION METER - SKID CONTROL ECU)
(a) Disconnect the E46 connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
* *1: w/o VSC
* *2: w/ VSC
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE COMBINATION METER
5. CHECK HARNESS AND CONNECTOR (COMBINATION METER - NO. 4 JUNCTION BLOCK)
(a) Disconnect the 4B connector.
(b) Measure the voltage according to the value(s) in the table below.
Standard Resistance:
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
6. CHECK HARNESS AND CONNECTOR (NO. 4 JUNCTION BLOCK)
(a) Inspect for a short in the circuit that is connected to the combination meter shown in the wiring diagram.
HINT
If voltage is not present, the circuit (ECU) was possibly the malfunctioning circuit. This is the circuit that will be diagnosed by following the A step that follows.
(1) Disconnect 4A connector.
(2) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
### ptxt ### *1: w/ Tire Pressure Warning System
### ptxt ### *2: w/ Smart Key System
Result:
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (NO. 4 JUNCTION BLOCK)
OK -- Continue to next step.
7. SYSTEM CHECK
(a) Select the circuit that did not present the voltage in the step 6.
Result:
* *1: w/ Tire Pressure Warning System
* *2: w/ Smart Key System
D -- CHECK HARNESS AND CONNECTOR (RADIO RECEIVER CIRCUIT)
C -- CHECK HARNESS AND CONNECTOR (MAIN BODY ECU CIRCUIT)
B -- CHECK HARNESS AND CONNECTOR (ECM CIRCUIT)
A -- Continue to next step.
8. CHECK HARNESS AND CONNECTOR (TIRE PRESSURE WARNING ECU CIRCUIT)
(a) Disconnect the E94 connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
* *: w/ Tire Pressure Warning System
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE TIRE PRESSURE WARNING ECU Removal
9. CHECK HARNESS AND CONNECTOR (ECM CIRCUIT)
(a) Disconnect the A50 connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Result:
C -- REPAIR OR REPLACE HARNESS OR CONNECTOR
B -- REPLACE ECM (for 2ZR-FE) Removal
A -- REPLACE ECM (for 2AZ-FE) Removal
10. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU CIRCUIT)
(a) Disconnect the 2C connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
* *: w/ Smart Key System
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE MAIN BODY ECU
11. CHECK HARNESS AND CONNECTOR (RADIO RECEIVER CIRCUIT)
(a) Disconnect the E26 connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE RADIO RECEIVER Removal
12. CHECK HARNESS AND CONNECTOR
(a) Inspect for a short in the circuit that is connected to the combination meter shown in the wiring diagram.
HINT
If voltage is not present, the circuit (ECU) was possibly the malfunctioning circuit.
(1) Disconnect the E26, E94*1, E100*2, E106*3, and 2E connectors.
### ptxt ### *1: w/ Tire Pressure Warning System
### ptxt ### *2: for Separate Type Amplifier System
### ptxt ### *3: w/ Navigation System
(2) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
13. INSPECT RADIO RECEIVER (CHECK FOR A SHORT)
(a) Disconnect the E26 connector.
(b) Measure the voltage according to the value(s) in the table below.
Standard Resistance:
NG -- REPLACE RADIO RECEIVER Removal
OK -- Continue to next step.
14. INSPECT TIRE PRESSURE WARNING ECU (CHECK FOR A SHORT)
HINT
If the vehicle does not equipped with the tire pressure warning system, proceed to the next step.
(a) Disconnect the E94 connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
* *: w/ Tire Pressure Warning System
NG -- REPLACE TIRE PRESSURE WARNING ECU Removal
OK -- Continue to next step.
15. INSPECT STEREO COMPONENT AMPLIFIER (CHECK FOR A SHORT)
HINT
If the vehicle does not equipped with the stereo component amplifier, proceed to the next step.
(a) Disconnect the E100 connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
* *: for Separate Type Amplifier System
NG -- REPLACE STEREO COMPONENT AMPLIFIER Removal
OK -- Continue to next step.
16. INSPECT NAVIGATION RECEIVER ASSEMBLY (CHECK FOR A SHORT)
HINT
If the vehicle does not equipped with the navigation system, proceed to the next step.
(a) Disconnect the E106 connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
* *: w/ Navigation System
NG -- REPLACE NAVIGATION RECEIVER ASSEMBLY Removal
OK -- Continue to next step.
17. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK)
(a) Inspect for a short in the circuit that is connected to the combination meter shown in the wiring diagram.
HINT
If voltage is not present, the circuit (ECU) was possibly the malfunctioning circuit. This is the circuit that will be diagnosed by following the A step that follows.
(1) Disconnect 2C, 2D, and 2Econnector.
(2) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
### ptxt ### *1: w/ Smart Key System
### ptxt ### *2: w/ Sliding Roof
Result:
B -- REPAIR OR REPLACE HARNESS OR CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK)
A -- Continue to next step.
18. SYSTEM CHECK
(a) Select the circuit that did not present the voltage in the step 17.
Result:
* *1: w/ Smart Key System
* *2: w/ Sliding Roof
C -- CHECK HARNESS AND CONNECTOR (SLIDING ROOF CONTROL ECU CIRCUIT)
B -- CHECK HARNESS AND CONNECTOR (MAIN BODY ECU CIRCUIT)
A -- Continue to next step.
19. CHECK HARNESS AND CONNECTOR (ECM CIRCUIT)
(a) Disconnect the A50 connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Result:
C -- REPAIR OR REPLACE HARNESS OR CONNECTOR
B -- REPLACE ECM (for 2ZR-FE) Removal
A -- REPLACE ECM (for 2AZ-FE) Removal
20. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU CIRCUIT)
(a) Disconnect the 2C connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
* *: w/ Smart Key System
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE MAIN BODY ECU
21. CHECK HARNESS AND CONNECTOR (SLIDING ROOF CONTROL ECU CIRCUIT)
(a) Disconnect the O11 connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
* *: w/ Sliding Roof
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE SLIDING ROOF CONTROL ECU Removal