Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Manual - part 1178

BRAKE CONTROL SYSTEM

5A–41

Chart B-3 Low or High Ignition Voltage (DTC 15 (Flash out) / C0277, 0278 (Serial
communications))

Chart B-4 Excessive Dump Time (DTC 17 (Flash out) / C0269 (Serial communications))

Chart B-5 Excessive Isolation Time (DTC 18 (Flash out) / C0274 (Serial communications))

Step

Action

Yes

No

1 

Is the battery voltage normal? (Battery capacity check)

Go to Step 2

Charge or 

replace battery.

Go to Step 2

2 

1. Turn the key off.

2. Disconnect coil integrated module connector.

3. Turn the key on.

Is the voltage between coil integrated module connector (C-4)
terminals 1 and 7, higher than 10V?

Check harness 

connector for 

suspected 

disconnection

Fault found: 

Repair, and 

perform system 

self-check

No fault found: 

replace EHCU.

Go to Step 3

Repair harness 

or connector.

Go to Step 3

3 

1. Reconnect all components, ensure all components are

properly mounted.

2. Clear diagnostic trouble code.

Was this step finished?

Repeat the “Basic 

diagnostic flow 

chart”

Go to Step 3

Step

Action

Yes

No

1 

Check for anything causing extended ABS activation, such as
locked brakes or an erratic speed sensor signal.
Was a problem found?

Repair or Replace

Go to Step 2

2 

1. The key turned off.

2. Replace EHCU.

3. Reconnect all components, ensure all components are

properly mounted.

Was this step finished?

Repeat the “Basic 

diagnostic flow 

chart”

Go to Step 2

Step

Action

Yes

No

1 

Check for anything causing extended ABS activation, such as
locked brakes or an erratic speed sensor signal.
Was a problem found?

Repair or Replace

Go to Step 2

2 

1. The key turned off.

2. Replace EHCU.

3. Reconnect all components, ensure all components are

properly mounted.

Was this step finished?

Repeat the “Basic 

diagnostic flow 

chart”

Go to Step 2

5A–42

BRAKE CONTROL SYSTEM

Chart B-6 G-Sensor Output Failure (DTC 21 (Flash out) / C0276 (Serial communications)) 

Chart B-7 Brake Switch Failure (DTC 22 (Flash out) / C0281 (Serial communications))

Step

Action

Yes

No

1 

1. Turn the key off.

2. Replace EHCU.

3. Reconnect all components, ensure all components are

properly mounted.

Was this step finished?

Repeat the “Basic 

diagnostic flow 

chart”

Go to Step 1

Step

Action

Yes

No

1 

Is the stop light actuated when the brake pedal is depressed?

Go to Step 2

Go to Step 4

2 

1. Turn the key off.

2. Disconnected coil integrated module connector.

Is the check voltage between coil integrated module connector
(C-4) terminals 13 to 7 when brake pedal is depressed the
battery voltage? 

Go to Step 3

Harness 

between brake 

SW and coil 

integrated 

module is faulty.

Go to Step 6

3 

Is the check that pins C-5 connector 2, and C-4 connector 7 have
good ground? 

Check harness 

/ connector for 

disconnection

Fault found: 

Repair, and 

perform system 

self-check.

No fault found: 

replace EHCU.

Go to Step 6

Repair.

Go to Step 6

4 

Is stop light fuse normal? 

Go to Step 5

Replace.

Go to Step 6

5 

Is brake SW normal?

Abnormal 

harness in stop 

light circuit.

Repair the 

harness.

Go to Step 6

Replace.

Go to Step 6

6 

1. Reconnect all components, ensure all components are

properly mounted.

2. Clear diagnostic trouble code.

Was this step finished?

Repeat the “Basic 

diagnostic flow 

chart”

Go to Step 6

BRAKE CONTROL SYSTEM

5A–43

Chart B-8 2WD Controller in 4WD Vehicle Controller (DTC 13 (Flash out) /   C0285 (Serial
communications)), 4WD State Input Signal Failure (DTC 24 (Flash out) / C0282 (Serial
communications))

Chart B-9 Pump Motor Failure (DTC 32 (Flash out) / C0267, C0268 (Serial communications))

Step

Action

Yes

No

1 

Remove coil integrated module connector.
Is the coil integrated module connector (C-4) terminal 8 line
normally?

Go to Step 2

Repair.

Go to Step 3 

2 

Is the 4WD controller normally?

Replace EHCU.

Go to Step 3 

Replace 4WD 

controller.

Go to Step 3 

3 

1. Reconnect all components, ensure all components are

properly mounted.

2. Clear diagnostic trouble code.

Was this step finished?

Repeat the “Basic 

diagnostic flow 

chart”

Go to Step 3

Step

Action

Yes

No

1 

1. Turn the key off.

2. Disconnect coil integrated module connector.

3. Measure the voltage between terminal 1 of the coil integrated

module connector (C-5) and body ground.

Is the voltage equal to the battery voltage?

Go to Step 2

Repair fuse/

harness 

between battery 

and coil 

integrated 

module 

connector (C-5) 

terminal 1.

Go to Step 5

2 

Is the harness from the hydraulic unit connected to the coil
integrated module connector?

Go to Step 3

Connect to the 

connector.

Go to Step 3

3 

Is the hydraulic unit harness in good condition?

Go to Step 4

Replace EHCU.

Go to Step 5

4 

Is the resistance of hydraulic unit connector terminals 1 and 2
between 0.2 and 1.0 ohms?

Replace EHCU.

Go to Step 5

Replace EHCU.

Go to Step 5

5 

1. Reconnect all components, ensure all components are

properly mounted.

2. Clear diagnostic trouble code.

Was this step finished?

Repeat the “Basic 

diagnostic flow 

chart”

Go to Step 5

5A–44

BRAKE CONTROL SYSTEM

Chart B-10 EHCU Valve Relay Failure (DTC 35 (Flash out) / C0265, C0266 (Serial
communications))

Chart B-11 FL Isolation Solenoid Coil Failure (DTC 41 (Flash out) / C0245, C0247 (Serial
communications))

Chart B-12 FL Dump Solenoid Coil Failure (DTC 42 (Flash out) / C0246, C0248 (Serial
communications))

Step

Action

Yes

No

1 

1. Turn the key off.

2. Disconnect coil integrated module connector.

3. Measure the voltage between terminal 1 of the coil integrated

module connector (C-5) and body ground.

Is the voltage equal to the battery voltage?

Replace EHCU.

Go to Step 2

Repair fuse and 

harness 

between coil 

integrated 

module 

connector (C-5) 

terminal 1 and 

battery.

Go to Step 2

2 

1. Reconnect all components, ensure all components are

properly mounted.

2. Clear diagnostic trouble code.

Was this step finished?

Repeat the “Basic 

diagnostic flow 

chart”

Go to Step 2

Step

Action

Yes

No

1 Was 

the 

“EHCU Connector Pin–out Checks” performed?

Go to Step 2

Go to “EHCU 

Connector Pin–out 

Checks.”

2 

1. Turn the key switch to off.

2. Disconnect the 2–way EHCU connector (C–5) from the

EHCU.

3. Inspect the connector for damage or corrosion.

Is the connector free from damage or corrosion?

Go to Step 3

Repair the 

connector. Repeat 

the “Basic 

Diagnostic Flow 

Chart.”

3 

1. Replace the Coil Integrated Module.

2. Reconnect all components, ensure all components are

properly mounted.

Was this step finished?

Repeat the “Basic 

diagnostic flow 

chart” 

Go to Step 3

Step

Action

Yes

No

1 Was 

the 

“EHCU Connector Pin–out Checks” performed?

Go to Step 2

Go to “EHCU 

Connector Pin–out 

Checks.”

2 

1. Turn the key switch to off.

2. Disconnect the 2–way EHCU connector (C–5) from the

EHCU.

3. Inspect the connector for damage or corrosion.

Is the connector free from damage or corrosion?

Go to Step 3

Repair the 

connector. Repeat 

the “Basic 

Diagnostic Flow 

Chart.”

3 

1. Replace the Coil Integrated Module.

2. Reconnect all components, ensure all components are

properly mounted.

Was this step finished?

Repeat the “Basic 

diagnostic flow 

chart” 

Go to Step 3