Speed Signal Circuit: Procedure
- INSPECT ECU TERMINAL VOLTAGE (INPUT VOLTAGE)
- Disconnect the L27 connector.
- Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection Condition Specified Condition L27-7 (+S) - Body ground Power switch on (IG) 4.5 to 14 V TEXT IN ILLUSTRATION*1 Front view of wire harness connector
(to Combination Meter Assembly (No. 3 Meter Circuit Plate))HINT:
If any of the ECUs specified in the wiring diagram supplies power to the combination meter assembly, the combination meter assembly will output a waveform.
NG → See step 5
OK: Go to next step
- INSPECT COMBINATION METER ASSEMBLY (NO. 3 METER CIRCUIT PLATE) (OUTPUT VOLTAGE)
- Reconnect the L27 connector.
- Disconnect the A58 connector.
- Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection Condition Specified Condition A58-11 (SP1) - Body ground Power switch on (IG) 11 to 14 V TEXT IN ILLUSTRATION*1 Front view of wire harness connector
(to Skid Control ECU)
NG → See step 4
OK: Go to next step
- INSPECT SKID CONTROL ECU (INPUT WAVEFORM)
- Check the input waveform.
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
- Reconnect the A58 connector.
- Remove the combination meter assembly with the connector(s) still connected.
- Connect an oscilloscope to terminal L27-8 (SI) and body ground.
- Turn the power switch on (IG).
- Turn the wheel slowly.
- Check the signal waveform according to the condition(s) in the table below.
Item Condition Tool setting 5 V/DIV., 20 ms./DIV. Vehicle condition Driving at approx. 20 km/h (12 mph) TEXT IN ILLUSTRATION*1 Component with harness connected
(Combination Meter Assembly)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.
NG → See step 20
OK → See step 19
- Check the input waveform.
- CHECK HARNESS AND CONNECTOR (NO. 3 METER CIRCUIT PLATE - SKID CONTROL ECU)
- Disconnect the L27 and A58 connectors.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition A58-11 (SP1) - L27-8 (SI) Always Below 1 Ω A58-11 (SP1) - Body ground Always 10 kΩ or higher
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK → See step 19
- CHECK HARNESS AND CONNECTOR (NO. 3 METER CIRCUIT PLATE - RADIO RECEIVER ASSEMBLY)
- Disconnect the L27 and L50 connectors.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition L50-3 (SPD) - L27-7 (+S) Always Below 1 Ω L50-3 (SPD) - Body ground Always 10 kΩ or higher
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: Go to next step
- INSPECT RADIO RECEIVER ASSEMBLY (OUTPUT VOLTAGE)
- Reconnect the L50 connector.
- Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection Condition Specified Condition L50-3 (SPD) - Body ground Power switch on (IG) 4 to 14 V TEXT IN ILLUSTRATION*1 Component with harness connected
(Radio Receiver Assembly)
NG → See step 21
OK: Go to next step
- CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - NO. 3 JUNCTION BLOCK)
- Disconnect the 3A connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition L27-7 (+S) - 3A-26 Always Below 1 Ω L27-7 (+S) - Body ground Always 10 kΩ or higher
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: Go to next step
- CHECK HARNESS AND CONNECTOR (NO. 3 JUNCTION BLOCK (INSTRUMENT PANEL WIRE))
- Inspect for a short in the circuit that is connected to the junction block connector shown in the wiring diagram.
HINT:
If voltage is not present, it is possible that an ECU or circuit has a malfunction. The malfunctioning ECU or circuit will be diagnosed in the following steps.
- Disconnect the 3B connector.
- Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection Condition Specified Condition 3A-2 - Body ground Power switch on (IG) 4.5 to 14 V 3B-1 - Body ground Power switch on (IG) 4.5 to 14 V 3B-85 - Body ground Power switch on (IG) 4.5 to 14 V TEXT IN ILLUSTRATION*1 Front view of wire harness connector
(to No. 3 Junction Block)Result
Result Proceed to Voltage is not present in one circuit. A Voltage is present in all the circuits. B
B → REPLACE NO. 3 JUNCTION BLOCK (INSTRUMENT PANEL WIRE)
A: Go to next step
- Inspect for a short in the circuit that is connected to the junction block connector shown in the wiring diagram.
- CHECK HARNESS AND CONNECTOR (NO. 3 JUNCTION BLOCK - NO. 4 JUNCTION BLOCK)
- Disconnect the 4A connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition 3B-85 - 4A-21 Always Below 1 Ω 3B-85 - Body ground Always 10 kΩ or higher
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: Go to next step
- CHECK HARNESS AND CONNECTOR (NO. 4 JUNCTION BLOCK (INSTRUMENT PANEL WIRE))
- Inspect for a short in the circuit that is connected to the junction block connector shown in the wiring diagram.
HINT:
If voltage is not present, it is possible that an ECU or circuit has a malfunction. The malfunctioning ECU or circuit will be diagnosed in the following steps.
- Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection Condition Specified Condition 4A-56 - Body ground Power switch on (IG) 4.5 to 14 V 4A-68 - Body ground Power switch on (IG) 4.5 to 14 V 4A-69 - Body ground Power switch on (IG) 4.5 to 14 V TEXT IN ILLUSTRATION*1 Front view of wire harness connector
(to No. 4 Junction Block)Result
Result Proceed to Voltage is not present in one circuit. A Voltage is present in all the circuits. B
- Measure the voltage according to the value(s) in the table below.
B → REPLACE NO. 4 JUNCTION BLOCK (INSTRUMENT PANEL WIRE)
A: Go to next step
- Inspect for a short in the circuit that is connected to the junction block connector shown in the wiring diagram.
- SYSTEM CHECK
- Select the circuit for which voltage was not present in step 7 or 9.
Result
Tester Connection System that Uses the Circuit Proceed to 3A-2 - Body ground Smart Key System A 4A-69 - Body ground Audio/Visual System A 4A-68*1 - Body ground Navigation System A 3B-1*2 - Body ground Tire Pressure Warning ECU A 4A-56*3 - Body ground Lighting System A 4A-80*4 - Body ground Safety Connect System B - *1: w/ Navigation System
- *2: w/ Tire Pressure Warning System
- *3: w/ Automatic Type Headlight Beam Level Control
- *4: w/ Manual (SOS) Switch
B → See step 18
A: Go to next step
- Select the circuit for which voltage was not present in step 7 or 9.
- SYSTEM CHECK
- Select the circuit for which voltage was not present in step 7 or 9.
Result
Tester Connection System that Uses the Circuit Proceed to 3A-2 - Body ground Smart Key System A 4A-69 - Body ground Audio/Visual System B 4A-68*1 - Body ground Navigation System C 3B-1*2 - Body ground Tire Pressure Warning ECU D 4A-56*3 - Body ground Lighting System E - *1: w/ Navigation System
- *2: w/ Tire Pressure Warning System
- *3: w/ Automatic Type Headlight Beam Level Control
E → See step 17
D → See step 16
C → See step 15
B → See step 14
A: Go to next step
- Select the circuit for which voltage was not present in step 7 or 9.
- CHECK HARNESS AND CONNECTOR (POWER MANAGEMENT CONTROL ECU CIRCUIT)
- Disconnect the L5 connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition L5-14 (SPDI) - Body ground Always 10 kΩ or higher
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK → See step 22
- CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER ASSEMBLY CIRCUIT)
- Disconnect the L31 connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition L31-11 (SPD) - Body ground Always 10 kΩ or higher
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK → See step 23
- CHECK HARNESS AND CONNECTOR (NAVIGATION RECEIVER ASSEMBLY CIRCUIT)
- Disconnect the L42 connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition L42-3 (SPD) - Body ground Always 10 kΩ or higher
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK → See step 24
- CHECK HARNESS AND CONNECTOR (TIRE PRESSURE WARNING ECU CIRCUIT)
- Disconnect the L4 connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition L4-2 (SPD) - Body ground Always 10 kΩ or higher
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK → See step 25
- CHECK HARNESS AND CONNECTOR (HEADLIGHT LEVELING ECU CIRCUIT)
- Disconnect the A48 connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition A48-16 (SPDR) - Body ground Always 10 kΩ or higher
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK → See step 26
- CHECK HARNESS AND CONNECTOR (DCM (TELEMATICS TRANSCEIVER) CIRCUIT)
- Disconnect the L19 connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition L19-10 (SPDP) - Body ground Always 10 kΩ or higher
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK → See step 27
- REPLACE COMBINATION METER ASSEMBLY (NO. 3 METER CIRCUIT PLATE). Refer to DISASSEMBLY
- REPLACE SKID CONTROL ECU. Refer to REMOVAL
- REPLACE RADIO RECEIVER ASSEMBLY. Refer to REMOVAL
- REPLACE POWER MANAGEMENT CONTROL ECU. Refer to REMOVAL
- REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY. Refer to REMOVAL
- REPLACE NAVIGATION RECEIVER ASSEMBLY. Refer to REMOVAL
- REPLACE TIRE PRESSURE WARNING ECU. Refer to REMOVAL
- REPLACE HEADLIGHT LEVELING ECU ASSEMBLY. Refer to REMOVAL
- REPLACE DCM (TELEMATICS TRANSCEIVER). Refer to REMOVAL