Refer to "54.Brake Control 4A.Troubleshooting(ABS/ESC) diagnostic System Check - Brake Controls".
1) Turn ON the ignition switch.
2) Check the ABS, ESC, and brake system warning lights. Does the warning light turn OFF after illuminating?
Yes
Go to Intermittent conditions of brake.
Refer to "205.Brakes 18D.Symptom intermittent conditions of brake".
No
=>Go to EHCU power supply voltage inspection.
1) Turn OFF the ignition switch.
2) Disconnect the EHCU harness connector (C13).
3) Turn ON the ignition switch.
4) Measure the voltage between the power supply circuit (pins 1, 25, and 28 of C13) and the ground circuit (pins 13 and 38 of C13) with a DMM. Is the voltage normal?
Refer to "RHD Anti-lock Brake" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "LHD Anti-lock Brake" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "RHD Electronic Stability Control" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "LHD Electronic Stability Control" in the ETM (wiring diagram). (Open using the ETM viewer.).
Value: 10 to 16 V
Yes
=>Go to EHCU harness connector inspection.
No
Repair the circuit as necessary.
Note
1) Turn OFF the ignition switch.
2) Inspect the connection status of the EHCU harness connector terminals (pins 1, 13, 25, 28, 38, 14, and 26 of C13). Is the connection status normal?
Refer to "RHD Anti-lock Brake" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "LHD Anti-lock Brake" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "RHD Electronic Stability Control" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "LHD Electronic Stability Control" in the ETM (wiring diagram). (Open using the ETM viewer.).
Yes
=>Go to Warning light illumination follow-up check.
No
Repair the circuit as necessary.
1) Turn OFF the ignition switch.
2) Securely connect the disconnected harness connectors.
3) Turn ON the ignition switch.
4) Check the ABS, ESC, and brake system warning lights. Does the warning light turn OFF after illuminating?
Yes
Go to Intermittent conditions of brake.
Refer to "205.Brakes 18D.Symptom intermittent conditions of brake".
No
=>Go to Instrument panel cluster warning light operation inspection.
1) Turn OFF the ignition switch.
2) Turn ON the ignition switch.
3) Inspect the operation of other warning lights excluding the ABS, ESC, and brake system warning lights. Is the result normal?
Yes
No
Replace the instrument panel cluster as necessary.
Note
Refer to "9.Body, Cab, Accessories 9E.Instrumentation, Driver Info. instrument panel cluster removal".
Refer to "9.Body, Cab, Accessories 9E.Instrumentation, Driver Info. instrument panel cluster installation".
Refer to "9.Body, Cab, Accessories 9E.Instrumentation, Driver Info. instrument panel cluster setting".
Note
Refer to "4.Brakes 4Z.Brake Electrical Control EHCU removal".
Refer to "4.Brakes 4Z.Brake Electrical Control EHCU installation".
Refer to "4.Brakes 4Z.Brake Electrical Control EHCU setting".
Procedure completion
1) Turn OFF the ignition switch.
2) Start the engine and drive the vehicle.
3) Check each warning light, as well as the vehicle behavior and drivability.
4) Does the vehicle run normally without any warning lights illuminating or a DTC being set?
Yes
The system is normal.
No
Go to applicable DTC diagnosis or Diagnosis by symptom.