Коды неисправностей и ремонт системы ABS 8 JAC N721
DTC - free failure repair
In a defective brake system, if no DTC is logged in ABS ECU, the failure is named as DTC - free failure. DTC free
failure is generally stemmed from base brake system faults, such as:
• Brake fluid leakage;
• Air in brake pipeline;
• Jammed brake pipeline;
• Over worn brake disc;
• Booster failure.
• Brake pipe wrong installation
Notice: ABS has no power supply or power interrupt can lead to ABS warning lamp on without DTC failure
code.
Countermeasure: check component corresponding to failure symptom.
Random failure repair
In electrical system, random failure might emerge from time to time owing to instantaneous loose contact in electrical circuit as well as signal in-out node. Sometimes the root cause of failure may disappear by itself, posing a barrier for excavating the underlying cause. For this reason, please abide by following means to identify the random failure.
If failure does not reoccur at this moment, diagnosis and repair will have to be postponed to the next time the failure reoccurs. Generally speaking, random failure will gradually turn into conventional failure, whereas an automatic disappearance is rarely seen.
DTC analysis
DTC list
Power supply overvoltage/undervoltage
DTC: C1900; C1901
DTC - logging condition
1) When ignition is on, and voltage is lower than 7.7V or higher than 16.8V;
2) When ignition is on, vehicle speed is higher than 6km/h, and voltage is within 7.7V – 9.3V.
Possible cause
• Battery overvoltage or undervoltage;
• Big battery load can cause low battery voltage.
Diagnosis procedure
Solenoid valve failure
DTC: C0010; C0011; C0014; C0015; C0018; C0019; C001C; C001D; C1095; C0072
DTC - logging condition:
1) After the ignition on, ECU detects that valve is short to battery/ground, or circuit is open.
2) Valve temperature too high.
3) More than 5 valves short.
4) No response is incurred after actuating a specific valve.
5) Valve malfunction.
6) Valve relay malfunction.
Possible cause:
• Valve is short to battery/ground, or circuit is open
• ECU not well grounded;
• Fuse failure;
• Valve system over heat;
• Damaged ECU.
Diagnosis procedure
Pump motor failure
DTC: C0020
DTC - logging condition:
1) Pump motor over heat;
2) After pump motor relay operates over 60ms, pump monitoring still fails to detect voltage signal;
3) Pump monitoring detects voltage continuously for 2.5s in spite of inactive pump motor relay;
4) Pump motor relay ceases operation, while pump monitoring detects no voltage decrease.
Possible cause:
• Pump motor not well grounded;
• Pump motor over heat protection;
• Pump motor power supply abnormal;
• Pump motor relay failure;
• Pump motor failure.
Diagnosis procedure
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