HAIMA 7 - Page 369

Anti-lock brake system (ABS control unit)
P-39
1
When the ignition switch is turned in the ON position, the alarm light of ABS control
unit is not lit
Tips of
troubleshooting
The alarm light line of ABS control unit alarm light is short circuited to earth
Steps Check items Operation
1
Do other indicator lights lighten up when the
ignition switch is turned to the ON position？
Yes
Confirm that no DTC saving exists. If
any savings do exist, repair them and
go to the next step.
No
Check and repair the PS circuit and
grounding line of instrument panel.
2
Does the alarm light of ABS control unit
lighten up when the control modular joint of
ABS control unit is disconnected and the
ignition switch turned on？
Yes
If the control modular of ABS control
unit is short-circuited, replace the
control modular of ABS control unit
No Go to the next step
3
Check whether the harnesses between the ABS
control unit control modular alarm light lead
and instrument are short circuited to earth？
Yes Repair the fault part.
No
Check and repair the alarm light
circuit in the instrument
2
The ignition switch is turned in the ON position, the alarm light of ABS control unit
keeps lit for more than 4s
Tips of
troubleshooting
ABS control unit detected the fault;
ABS control unit detected the too low of power voltage;
CM of ABS control unit doesn’t work;
The alarm light line of ABS control unit is circuit-broken.
Steps Test items Operation
1
Whether the control modular joint of ABS
control unit is in good connection？
Yes Go to the step 3
No
Connect the joint properly and go to
the next step
2
Whether the alarm light of ABS control unit
goes off when it is lightened up in 4s after the
ignition switch is turned on？
Yes
Poor joint contact in short time. Check
the modular joint and lead of ABS
control unit control
No Go to the next step
3
Carry out the diagnostic check of fault codes.
See——Reappearance of Diagnostic Function,
ABS Control Unit/TCS, DTC Test, whether the
DTC has been recorded？
Yes
Carry out the inspection according to
the DTC
No Go to the next step
4 Whether the battery voltage is normal？
Yes Go to the next step
No Check the battery and charge system.
5
Whether the battery is normal, when the engine
runs idle and has electric load？
Yes to the next step
No Check the charge system
Steps Test items Operation