| DTC Code | DTC Name |
|---|---|
| C1A4B | Stop Light Relay Circuit |
DESCRIPTION
The skid control ECU (brake booster with master cylinder assembly) sends a stop light operation request signal to the stop light relay (stop light switch assembly). If the skid control ECU (brake booster with master cylinder assembly) detects a malfunction in the stop light relay circuit, the driving support ECU assembly stores DTC C1A4B.
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area |
|---|---|---|---|
| C1A4B | Stop Light Relay Circuit | Both of the following conditions are met:
Tech Tips The skid control ECU (brake booster with master cylinder assembly) will detect a stop light relay circuit malfunction if any of the following conditions are met:
|
|
WIRING DIAGRAM
CAUTION / NOTICE / HINT
Note
Inspect the fuses for circuits related to this system before performing the following procedure.
PROCEDURE
INSPECT TERMINAL VOLTAGE (SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) CONNECTOR)
Turn the power switch off.
| *a | Front view of wire harness connector (to Skid control ECU (Brake booster with master cylinder assembly)) |
Disconnect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
Measure the voltage according to the value(s) in the table below.
| Standard Voltage | ||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Connect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
| Result | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
| B |
|
INSPECT TERMINAL VOLTAGE (SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) CONNECTOR) Click here |
| C |
|
CHECK WIRE HARNESS AND CONNECTOR (SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) - STOP LIGHT RELAY (STOP LIGHT SWITCH ASSEMBLY)) Click here |
| D |
|
INSPECT TERMINAL VOLTAGE (SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) CONNECTOR) Click here |
| E |
|
INSPECT STOP LIGHT RELAY (STOP LIGHT SWITCH ASSEMBLY) (POWER SOURCE CIRCUIT) Click here |
| A |
|
PERFORM ACTIVE TEST USING GTS (STOP LIGHT RELAY)
Turn the power switch off.
According to the display on the GTS, perform the Active Test Stop Light Relay.
| Tester Display | Measurement Item | Control Range | Diagnostic Note |
|---|---|---|---|
| Stop Light Relay | Stop light relay (Stop light switch assembly) | ON / OFF | Test possible at vehicle speed of 0 km/h (0 mph) |
| Tester Display |
|---|
| Stop Light Relay |
| OK |
|---|
| The stop lights turn on and off correctly in response to the operation of the Active Test. |
| Result | |||
|---|---|---|---|
|
| NG |
|
INSPECT SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) Click here |
| OK |
|
CHECK FOR DTCS (PRE-CRASH SAFETY SYSTEM)
Clear the DTCs.
According to the display on the GTS, perform the Active Test Stop Light Relay.
| Tester Display | Measurement Item | Control Range | Diagnostic Note |
|---|---|---|---|
| Stop Light Relay | Stop light relay (Stop light switch assembly) | ON / OFF | Test possible at vehicle speed of 0 km/h (0 mph) |
| Tester Display |
|---|
| Stop Light Relay |
Check for DTCs.
| OK |
|---|
| DTC C1A4B is not output |
| Result | |||
|---|---|---|---|
|
| OK |
|
USE SIMULATION METHOD TO CHECK Click here |
| NG |
|
REPLACE SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) for LHD: Click here for RHD: Click here |
INSPECT SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY)
According to the display on the GTS, perform the Active Test Stop Light Relay.
| Tester Display | Measurement Item | Control Range | Diagnostic Note |
|---|---|---|---|
| Stop Light Relay | Stop light relay (Stop light switch assembly) | ON / OFF | Test possible at vehicle speed of 0 km/h (0 mph) |
| Tester Display |
|---|
| Stop Light Relay |
| *a | Component with harness connected (Stop light relay (stop light switch assembly)) |
Measure the voltage according to the value(s) in the table below.
Tech Tips
Do not disconnect the stop light relay (stop light switch assembly) connector.
| Standard Voltage | ||||||
|---|---|---|---|---|---|---|
|
| Result | |||
|---|---|---|---|
|
| OK |
|
REPLACE STOP LIGHT RELAY (STOP LIGHT SWITCH ASSEMBLY) Click here |
| NG |
|
REPLACE SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) for LHD: Click here for RHD: Click here |
INSPECT TERMINAL VOLTAGE (SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) CONNECTOR)
Turn the power switch off.
| *a | Front view of wire harness connector (to Skid control ECU (Brake booster with master cylinder assembly)) |
Disconnect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
Measure the voltage according to the value(s) in the table below.
| Standard Voltage | ||||||
|---|---|---|---|---|---|---|
|
Connect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
| Result | |||
|---|---|---|---|
|
| NG |
|
CHECK WIRE HARNESS AND CONNECTOR (SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) - STOP LIGHT RELAY (STOP LIGHT SWITCH ASSEMBLY)) Click here |
| OK |
|
CHECK WIRE HARNESS AND CONNECTOR (SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) - CERTIFICATION ECU (SMART KEY ECU ASSEMBLY))
Turn the power switch off.
Disconnect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
Disconnect the N54 certification ECU (smart key ECU assembly) connector.
Measure the voltage according to the value(s) in the table below.
| Standard Voltage | ||||||
|---|---|---|---|---|---|---|
|
Connect the N54 certification ECU (smart key ECU assembly) connector.
Connect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
| Result | |||
|---|---|---|---|
|
| OK |
|
REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) |
| NG |
|
CHECK WIRE HARNESS AND CONNECTOR (SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) - HYBRID VEHICLE CONTROL ECU)
Turn the power switch off.
Disconnect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
Disconnect the A41 hybrid vehicle control ECU connector.
Measure the voltage according to the value(s) in the table below.
| Standard Voltage | ||||||
|---|---|---|---|---|---|---|
|
Connect the A41 hybrid vehicle control ECU connector.
Connect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
| Result | |||
|---|---|---|---|
|
| OK |
|
REPLACE HYBRID VEHICLE CONTROL ECU Click here |
| NG |
|
CHECK WIRE HARNESS AND CONNECTOR (SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) - STOP LIGHT RELAY (STOP LIGHT SWITCH ASSEMBLY))
Turn the power switch off.
Disconnect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
Disconnect the A38 stop light relay (stop light switch assembly) connector.
Measure the resistance according to the value(s) in the table below.
| Standard Resistance | |||||||||
|---|---|---|---|---|---|---|---|---|---|
|
Connect the A38 stop light relay (stop light switch assembly) connector.
Connect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
| Result | |||
|---|---|---|---|
|
| OK |
|
REPLACE STOP LIGHT RELAY (STOP LIGHT SWITCH ASSEMBLY) Click here |
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
CHECK WIRE HARNESS AND CONNECTOR (SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) - STOP LIGHT RELAY (STOP LIGHT SWITCH ASSEMBLY))
Turn the power switch off.
Disconnect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
Disconnect the A38 stop light relay (stop light switch assembly) connector.
Measure the voltage according to the value(s) in the table below.
| Standard Voltage | ||||||
|---|---|---|---|---|---|---|
|
Connect the A38 stop light relay (stop light switch assembly) connector.
Connect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
| Result | |||
|---|---|---|---|
|
| OK |
|
REPLACE STOP LIGHT RELAY (STOP LIGHT SWITCH ASSEMBLY) Click here |
| NG |
|
CHECK WIRE HARNESS AND CONNECTOR (SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) - CERTIFICATION ECU (SMART KEY ECU ASSEMBLY))
Turn the power switch off.
Disconnect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
Disconnect the N54 certification ECU (smart key ECU assembly) connector.
Measure the voltage according to the value(s) in the table below.
| Standard Voltage | ||||||
|---|---|---|---|---|---|---|
|
Connect the N54 certification ECU (smart key ECU assembly) connector.
Connect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
| Result | |||
|---|---|---|---|
|
| OK |
|
REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) |
| NG |
|
CHECK WIRE HARNESS AND CONNECTOR (SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) - HYBRID VEHICLE CONTROL ECU)
Turn the power switch off.
Disconnect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
Disconnect the A41 hybrid vehicle control ECU connector.
Measure the voltage according to the value(s) in the table below.
| Standard Voltage | ||||||
|---|---|---|---|---|---|---|
|
Connect the A41 hybrid vehicle control ECU connector.
Connect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
| Result | |||
|---|---|---|---|
|
| OK |
|
REPLACE HYBRID VEHICLE CONTROL ECU Click here |
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
CHECK WIRE HARNESS AND CONNECTOR (SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) - STOP LIGHT RELAY (STOP LIGHT SWITCH ASSEMBLY))
Turn the power switch off.
Disconnect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
Disconnect the A38 stop light relay (stop light switch assembly) connector.
Measure the resistance according to the value(s) in the table below.
| Standard Resistance | ||||||
|---|---|---|---|---|---|---|
|
Connect the A38 stop light relay (stop light switch assembly) connector.
Connect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
| Result | |||
|---|---|---|---|
|
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
| OK |
|
INSPECT STOP LIGHT RELAY (STOP LIGHT SWITCH ASSEMBLY) (POWER SOURCE CIRCUIT)
Turn the power switch off.
| *a | Front view of wire harness connector (to Stop light relay (Stop light switch assembly)) |
Disconnect the A38 stop light relay (stop light switch assembly) connector.
Measure the voltage according to the value(s) in the table below.
| Standard Voltage | |||||||||
|---|---|---|---|---|---|---|---|---|---|
|
Measure the resistance according to the value(s) in the table below.
| Standard Resistance | ||||||
|---|---|---|---|---|---|---|
|
Connect the A38 stop light relay (stop light switch assembly) connector.
| Result | |||
|---|---|---|---|
|
| OK |
|
REPLACE STOP LIGHT RELAY (STOP LIGHT SWITCH ASSEMBLY) Click here |
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
INSPECT TERMINAL VOLTAGE (SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) CONNECTOR)
Turn the power switch off.
| *a | Front view of wire harness connector (to Skid control ECU (Brake booster with master cylinder assembly)) |
Disconnect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
Measure the voltage according to the value(s) in the table below.
| Standard Voltage | ||||||
|---|---|---|---|---|---|---|
|
Connect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
| Result | |||
|---|---|---|---|
|
| NG |
|
CHECK WIRE HARNESS AND CONNECTOR (SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) - STOP LIGHT RELAY (STOP LIGHT SWITCH ASSEMBLY)) Click here |
| OK |
|
CHECK WIRE HARNESS AND CONNECTOR (SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) - REAR COMBINATION LIGHT ASSEMBLY LH)
Turn the power switch off.
Disconnect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
Disconnect the N37 rear combination light assembly LH connector.
Measure the voltage according to the value(s) in the table below.
| Standard Voltage | ||||||
|---|---|---|---|---|---|---|
|
Connect the N37 rear combination light assembly LH connector.
Connect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
| Result | |||
|---|---|---|---|
|
| OK |
|
REPLACE REAR COMBINATION LIGHT ASSEMBLY LH Click here |
| NG |
|
CHECK WIRE HARNESS AND CONNECTOR (SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) - REAR COMBINATION LIGHT ASSEMBLY RH)
Turn the power switch off.
Disconnect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
Disconnect the N36 rear combination light assembly RH connector.
Measure the voltage according to the value(s) in the table below.
| Standard Voltage | ||||||
|---|---|---|---|---|---|---|
|
Connect the N36 rear combination light assembly RH connector.
Connect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
| Result | |||
|---|---|---|---|
|
| OK |
|
REPLACE REAR COMBINATION LIGHT ASSEMBLY RH Click here |
| NG |
|
CHECK WIRE HARNESS AND CONNECTOR (SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) - CENTER STOP LIGHT SET)
Turn the power switch off.
Disconnect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
Disconnect the R7 center stop light set connector.
Measure the voltage according to the value(s) in the table below.
| Standard Voltage | ||||||
|---|---|---|---|---|---|---|
|
Connect the R7 center stop light set connector.
Connect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
| Result | |||
|---|---|---|---|
|
| OK |
|
REPLACE CENTER STOP LIGHT SET Click here |
| NG |
|
CHECK WIRE HARNESS AND CONNECTOR (SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) - STOP LIGHT RELAY (STOP LIGHT SWITCH ASSEMBLY))
Turn the power switch off.
Disconnect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
Disconnect the A38 stop light relay (stop light switch assembly) connector.
Measure the resistance according to the value(s) in the table below.
| Standard Resistance | |||||||||
|---|---|---|---|---|---|---|---|---|---|
|
Connect the A38 stop light relay (stop light switch assembly) connector.
Connect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
| Result | |||
|---|---|---|---|
|
| OK |
|
REPLACE STOP LIGHT RELAY (STOP LIGHT SWITCH ASSEMBLY) Click here |
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
CHECK WIRE HARNESS AND CONNECTOR (SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) - STOP LIGHT RELAY (STOP LIGHT SWITCH ASSEMBLY))
Turn the power switch off.
Disconnect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
Disconnect the A38 stop light relay (stop light switch assembly) connector.
Measure the voltage according to the value(s) in the table below.
| Standard Voltage | ||||||
|---|---|---|---|---|---|---|
|
Connect the A38 stop light relay (stop light switch assembly) connector.
Connect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
| Result | |||
|---|---|---|---|
|
| OK |
|
REPLACE STOP LIGHT RELAY (STOP LIGHT SWITCH ASSEMBLY) Click here |
| NG |
|
CHECK WIRE HARNESS AND CONNECTOR (SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) - REAR COMBINATION LIGHT ASSEMBLY LH)
Turn the power switch off.
Disconnect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
Disconnect the N37 rear combination light assembly LH connector.
Measure the voltage according to the value(s) in the table below.
| Standard Voltage | ||||||
|---|---|---|---|---|---|---|
|
Connect the N37 rear combination light assembly LH connector.
Connect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
| Result | |||
|---|---|---|---|
|
| OK |
|
REPLACE REAR COMBINATION LIGHT ASSEMBLY LH Click here |
| NG |
|
CHECK WIRE HARNESS AND CONNECTOR (SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) - REAR COMBINATION LIGHT ASSEMBLY RH)
Turn the power switch off.
Disconnect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
Disconnect the N36 rear combination light assembly RH connector.
Measure the voltage according to the value(s) in the table below.
| Standard Voltage | ||||||
|---|---|---|---|---|---|---|
|
Connect the N36 rear combination light assembly RH connector.
Connect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
| Result | |||
|---|---|---|---|
|
| OK |
|
REPLACE REAR COMBINATION LIGHT ASSEMBLY RH Click here |
| NG |
|
CHECK WIRE HARNESS AND CONNECTOR (SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) - CENTER STOP LIGHT SET)
Turn the power switch off.
Disconnect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
Disconnect the R7 center stop light set connector.
Measure the voltage according to the value(s) in the table below.
| Standard Voltage | ||||||
|---|---|---|---|---|---|---|
|
Connect the R7 center stop light set connector.
Connect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
| Result | |||
|---|---|---|---|
|
| OK |
|
REPLACE CENTER STOP LIGHT SET Click here |
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
INSPECT STOP LIGHT RELAY (STOP LIGHT SWITCH ASSEMBLY) (POWER SOURCE CIRCUIT)
Turn the power switch off.
| *a | Front view of wire harness connector (to Stop light relay (Stop light switch assembly)) |
Disconnect the A38 stop light relay (stop light switch assembly) connector.
Measure the voltage according to the value(s) in the table below.
| Standard Voltage | |||||||||
|---|---|---|---|---|---|---|---|---|---|
|
Measure the resistance according to the value(s) in the table below.
| Standard Resistance | ||||||
|---|---|---|---|---|---|---|
|
Connect the A38 stop light relay (stop light switch assembly) connector.
| Result | |||
|---|---|---|---|
|
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
| OK |
|
CHECK WIRE HARNESS AND CONNECTOR (SKID CONTROL ECU (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) - STOP LIGHT RELAY (STOP LIGHT SWITCH ASSEMBLY))
Turn the power switch off.
Disconnect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
Disconnect the A38 stop light relay (stop light switch assembly) connector.
Measure the resistance according to the value(s) in the table below.
| Standard Resistance | ||||||
|---|---|---|---|---|---|---|
|
Connect the A38 stop light relay (stop light switch assembly) connector.
Connect the A32 skid control ECU (brake booster with master cylinder assembly) connector.
| Result | |||
|---|---|---|---|
|
| OK |
|
REPLACE STOP LIGHT RELAY (STOP LIGHT SWITCH ASSEMBLY) Click here |
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |