Find here extended description, connector views, and help for diagnostic as well !
- 24V key slot
- Conforms to IP67 when mated with ISO7638 connections
- Cable insulation material : PVC
ISO7638 socket - ISO7638 plug
Pin | Description | Color | Section (mm2) |
---|---|---|---|
1 | B+ Permanent | Red | 4 |
2 | B+ Ignition | Black | 1.5 |
3 | B- Ignition | Yellow | 1.5 |
4 | B- Permanent | Brown | 4 |
5 | Lamp return | White | 1.5 |
6 | CAN High | White-green | 1.5 |
7 | CAN Low | White-brown | 1.5 |
Diagnostic
ISO7638 connection is the mandatory power supply for ABS/EBS systems. If the system is showing a wrong function, the power supply must be the first step of the diagnostic!
Before to use the table below, first check the reaction of the system at power ON, either with service brake applied (Brake pedal) or with the red coupling head disconnected (Emergency braking mode) or with the yellow line supplied (At 6.5 bar air pressure).
When switching power ON
- Each modulator exhausts one time (the number of exhausts must be the same as the number of modulators).
- ABS warning lamp on dashboard indicates a specific sequence (ON/OFF) or (ON/OFF/ON)
If not, check power supply :
Test points (with 21W lamp) |
Condition | Required value | Measured value | Comments |
---|---|---|---|---|
Power-A plug 1 - 4 |
ISO7638 connected Switch power OFF |
B+ |
If permanent power is missing (0V), solenoids are not powered. If measured value is below B+ (voltage drop), it can indicate a resistance in the wiring. Next steps :
|
|
Power-A plug 2 - 3 |
ISO7638 connected Switch power OFF |
0V |
A permanent power indicates a wrong wiring or short circuit. Next steps :
|
|
Power-A plug 2 - 3 |
ISO7638 connected Switch power ON |
B+ |
If switch power is missing, ECU is not powered. If measured value is below B+ (voltage drop), it can indicate a resistance in the wiring. Next steps :
|
Diagnostic
ISO11992 - EBS only
The ISO11992 is a mandatory connection between trucks and trailers. Several messages are sended from both side to the other.
This communication is also used for diagnostic purpose. In the ISO7638 connection, Pin 6 and 7 are used for this communication bus (CAN High and CAN Low).
Test points | Condition | Required value | Mesured value | Comments |
---|---|---|---|---|
6 - 4 | Power ON |
CAN High is around 2/3 of B+ Usually between 12V and 18V |
The required value depend of the load on the CAN bus (amount of message, internal resistance of ECU) Next step :
|
|
7 - 4 | Power ON |
CAN low is around 1/3 of B+ Usually between 6V and 10V |
The required value depend of the load on the CAN bus (amount of message, internal resistance of ECU) Next step :
|