Speed Signal Circuit: Procedure
- INSPECT COMBINATION METER ASSEMBLY
- Check the output waveform.
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
- Remove the combination meter assembly with connector(s) still connected.
- Connect the oscilloscope to the terminals E20-12 (+S) and body ground.
- Turn the engine 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) OK
The waveform is displayed as shown.
HINT:
When the system is functioning normally, one wheel revolution generates 4 pulses. As the vehicle speed increases, the width indicated by (A) narrows.
NG → See step 2
OK → RETURN TO THE ORIGINAL INSPECTION FOR OTHER SYSTEM
- Check the output waveform.
- INSPECT ECU TERMINAL VOLTAGE
- Disconnect the E20 connector.
- Measure the voltage according to the value(s) in the table below.
Standard voltage
Tester Connection Condition Specified Condition E20-12 (+S) - Body ground Turn the ignition switch on (IG) 4.5 to 14 V HINT:
If any of the ECUs specified in the wiring diagram supplied power to the combination meter, the combination meter will output a waveform.
NG → See step 5
OK: Go to next step
- INSPECT COMBINATION METER ASSEMBLY
- Reconnect the E20 connector.
- Disconnect the A36 connector.
- Measure the voltage according to the value(s) in the table below.
Standard voltage
Tester Connection Condition Specified Condition A36-12 (SP1) - Body ground Turn the engine switch on (IG) 10 to 14 V
NG → See step 20
OK: Go to next step
- INSPECT SKID CONTROL ECU
- Check the input waveform.
- Reconnect the A36 connector.
- Remove the combination meter assembly with connector(s) still connected.
- Connect the oscilloscope to the terminals E20-14 (SI) and body ground.
- Turn the engine 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) OK
The waveform is displayed as shown.
HINT:
When the system is functioning normally, one wheel revolution generates 4 pulses. As the vehicle speed increases, the width indicated by (A) narrows.
NG → REPLACE SKID CONTROL ECU
OK → REPLACE COMBINATION METER ASSEMBLY
- Check the input waveform.
- CHECK HARNESS AND CONNECTOR (COMBINATION METER - NO. 3 JUNCTION BLOCK)
- Disconnect the 3P to 3U No. 3 junction block connector.
- Measure the resistance according to the value(s) in the table below.
Standard resistance
Tester Connection Condition Specified Condition E20-12 (+S) - 3P-6 Always Below 1 Ω E20-12 (+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)
- Inspect for a short in the circuit that connected the No. 3 junction block 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.
- Disconnect the 3G to 3M and 3A to 3H No. 3 junction block connectors.
- Measure the voltage according to the value(s) in the table below.
Standard voltage
Tester Connection Condition Specified Condition 3A-7 - Body ground Turn the engine switch on (IG) 4.5 to 14 V 3F-5 - Body ground Turn the engine switch on (IG) 4.5 to 14 V 3H-6 - Body ground Turn the engine switch on (IG) 4.5 to 14 V Result
Result Proceed to Voltage is not present in one circuit A Voltage is present in all the circuit. B
B → REPAIR OR REPLACE HARNESS OR CONNECTOR (NO. 3 JUNCTION BLOCK)
A: Go to next step
- Inspect for a short in the circuit that connected the No. 3 junction block shown in the wiring diagram.
- CHECK HARNESS AND CONNECTOR (NO. 3 JUNCTION BLOCK - NO. 4 JUNCTION BLOCK)
- Disconnect the 4H to 4M No. 4 junction block connector.
- Measure the resistance according to the value(s) in the table below.
Standard resistance
Tester Connection Condition Specified Condition 3F-5 - 4M-8 Always Below 1 Ω 4M-8 - 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)
- Disconnect the 4A to 4G No. 4 junction block connector.
- Measure the voltage according to the value(s) in the table below.
Standard voltage
Tester Connection Condition Specified Condition 4D-7 - Body ground Turn the engine switch on (IG) 4.5 to 14 V 4E-7 - Body ground Turn the engine switch on (IG) 4.5 to 14 V 4K-7 - Body ground Turn the engine switch on (IG) 4.5 to 14 V 4G-7 - Body ground Turn the engine switch on (IG) 4.5 to 14 V 4J-7 - Body ground Turn the engine switch on (IG) 4.5 to 14 V
B → REPAIR OR REPLACE HARNESS AND CONNECTOR (NO. 4 JUNCTION BLOCK)
A: Go to next step
- SYSTEM CHECK
- Select the circuit in which is not present voltage in step 6.
Result
Tester Connection System That Uses the Circuit Proceed to 3A-7 - Body ground Smart Access System with Push-button Start System A 3H-6 - Body ground Tire Pressure Warning System (*1) B 3F-5 - Body ground SFI System, Automatic Transaxle System, Wiper and Washer System, Navigation System (*2), Audio/visual System (*3), Lexus Enform System (*4) C *1: w/ Tire Pressure Warning System
*2: w/ Navigation System
*3: w/o Navigation System
*4: w/ Manual (SOS) Switch
B → See step 11
C → See step 12
A: Go to next step
- Select the circuit in which is not present voltage in step 6.
- CHECK HARNESS AND CONNECTOR (MAIN BODY ECU CIRCUIT)
- Disconnect the E59 connector.
- Measure the resistance according to the value(s) in the table below.
Standard resistance
Tester Connection Condition Specified Condition E59-9 (SPD)- Body ground Always 10 kΩ or higher
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK → REPLACE MAIN BODY ECU
- CHECK HARNESS AND CONNECTOR (TIRE PRESSURE WARNING ECU CIRCUIT)
- Disconnect the E81 connector.
- Measure the resistance according to the value(s) in the table below.
Standard resistance
Tester Connection Condition Specified Condition E81-2 (SPD) Body ground Always 10 kΩ or higher
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK → REPLACE TIRE PRESSURE WARNING ECU
- SYSTEM CHECK
- Select the circuit in which is not present voltage in step 8.
Result
Tester Connection System That Uses the Circuit Proceed to 4E-7 - Body ground SFI System, Automatic Transaxle System A 4J-7 - Body ground Wiper and Washer System B 4G-7 - Body ground Navigation System (*1) C 4D-7 - Body ground Audio/Visual System D 4K-7 - Body ground Audio/Visual System (*2), Lexus Enform System (*3) E *1: w/ Navigation System
*2: w/o Navigation System
*3: w/ Manual (SOS) Switch
B → See step 14
C → See step 15
D → See step 16
E → See step 17
A: Go to next step
- Select the circuit in which is not present voltage in step 8.
- CHECK HARNESS AND CONNECTOR (ECM CIRCUIT, TCM CIRCUIT)
- Disconnect the A10 connector.
- Measure the resistance according to the value(s) in the table below.
Standard resistance
Tester Connection Condition Specified Condition A10-8 (SPD) - Body ground Always 10 kΩ or higher - Disconnect the B40 connector.
- Measure the resistance according to the value(s) in the table below.
Standard resistance
Tester Connection Condition Specified Condition B40-3 (SPD1) - Body ground Always 10 kΩ or higher Result
Result Proceed to OK (for SFI System) A OK (for Automatic Transaxle System) B NG C
B → REPLACE TCM
C → REPAIR OR REPLACE HARNESS OR CONNECTOR
A → REPLACE ECM
- CHECK HARNESS AND CONNECTOR (WINDSHIELD WIPER RELAY CIRCUIT)
- Disconnect the E11 connector.
- Measure the resistance according to the value(s) in the table below.
Standard resistance
Tester Connection Condition Specified Condition E11-19 (SPD) - Body ground Always 10 kΩ or higher
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK → REPLACE WINDSHIELD WIPER RELAY
- CHECK HARNESS AND CONNECTOR (DISPLAY AND NAVIGATION MODULE DISPLAY CIRCUIT)
- Disconnect the E62 connector.
- Measure the resistance according to the value(s) in the table below.
Standard resistance
Tester Connection Condition Specified Condition E62-18 (SPD) - Body ground Always 10 kΩ or higher
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK → REPLACE DISPLAY AND NAVIGATION MODULE DISPLAY
- CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER CIRCUIT)
- Disconnect the M30 (*1) or M36 (*2) connector.
- Measure the resistance according to the value(s) in the table below.
Standard resistance
Tester Connection Condition Specified Condition M30-11 (SPD) (*1) - Body ground Always 10 kΩ or higher M36-2 (SPD) (*2) - Body ground Always 10 kΩ or higher *1: w/o Navigation System
*2: w/ Navigation System
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK → REPLACE STEREO COMPONENT AMPLIFIER
- SYSTEM CHECK
- Select the circuit in which is not present voltage in step 8.
Result
Tester Connection System That Uses the Circuit Proceed to 4K-7 - Body ground Audio/Visual System (*1) A 4K-7 - Body ground Lexus Enform System (*2) B *1: w/o Navigation System
*2: w/ Manual (SOS) Switch
B → See step 19
A: Go to next step
- Select the circuit in which is not present voltage in step 8.
- CHECK HARNESS AND CONNECTOR (RADIO RECEIVER CIRCUIT)
- Disconnect the E70 connector.
- Measure the resistance according to the value(s) in the table below.
Standard resistance
Tester Connection Condition Specified Condition E70-3 (SPD) - Body ground Always 10 kΩ or higher
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK → REPLACE RADIO RECEIVER
- CHECK HARNESS AND CONNECTOR (DCM (TELEMATICS TRANSCEIVER) CIRCUIT)
- Disconnect the E97 connector.
- Measure the resistance according to the value(s) in the table below.
Standard resistance
Tester Connection Condition Specified Condition E97-10 (SPDP) Body ground Always 10 kΩ or higher
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK → REPLACE DCM (TELEMATICS TRANSCEIVER)
- CHECK HARNESS AND CONNECTOR (COMBINATION METER - SKID CONTROL ECU)
- Disconnect the E20 connector.
- Measure the resistance according to the value(s) in the table below.
Standard resistance
Tester Connection Condition Specified Condition A36-12 (SP1) - E20-14 (SI) Always Below 1 Ω A36-12 (SP1) - Body ground Always 10 kΩ or higher
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK → REPLACE COMBINATION METER ASSEMBLY