Comunicare CAN cuplaj Haldex

Erori de comunicare CAN cuplaj Haldex

   Cum sa verificam alimentarea 12 volt si comunicarea pe CAN la modul electronic cuplaj AWD Haldex

    Hello! Today I will talk about the situation when there is no connection with the Haldex control unit.

As an example, there is a car volvo xc70 2006. The rear differential does not turn on.

VIDA gives an error - there is no communication with the Haldex control unit.

Here are examples of such errors. They are registered in the ABS module.

When trying to communicate with the 4x4 module, we get the answer that there is no connection.

We will look for a malfunction

1. Check if there is a supply voltage of 12 volts to the input of the Haldex control unit.

2. Check if there is a control signal on the CAN line to the input of the Haldex control unit.

Need a bulb of 12 volts P21/5W and a multimeter.

We need two wires 5 meters long.

The control unit has two groups of contacts.

The first is 8 pin. Second - 2 pin

Ignition ON. The engine is running. Both pin groups are disabled.

Pin 1 and pin 2 should be 12 volts. In my case, there is no voltage.

You need to understand the reason. No plus 12 volts or not minus 12 volts.

I use two wires of 5 meters. I connected the wires to the car battery.

Step 1

I measure the voltage between the +12 volt wire and pin 1 and pin 2.

There is 12 volts between the wire with +12 volts and pin 2. So -12 volts goes to the control unit.

Step 2

I measure the voltage between the -12 volt wire and pin 1 and pin 2.

No 12 volts. So +12 volts does not go to the control unit.

Step 3

Checking the fuse. He is defective.

There is a short circuit in the control unit or in the oil pump. I want to know where?

I turn off the ignition. The second group of contacts is disconnected (2 pins) (output to the pump).

There are two diagnostic options.

1. In the place of the fuse, turn on the 12-volt and 55-watt lamp. I start the car engine.

The lamp illuminates at half the power - there is no short circuit in the control unit.

The lamp illuminates at full power - there is a short circuit in the control unit.

2. Insert a 5-7.5 amp fuse. I start the car engine.

If burned out, there is a short circuit.

In my case, the fuse is blown.

Opened the control unit. And there is ...

Step 4

Checking the CAN line. I measure the voltage between pin 2 and 7, 2 and 8.

It should be 2.1-2.3 volts, 2.6-2.9 volts, respectively.

I measure the resistance between pin 7 and pin 8. It should be 58 - 62 ohms.

I measure the resistance between the minus of the car and pin 7 and pin 8.

It must be infinity. If there is resistance, then there is a malfunction.

Need to contact the electronics.

Suppose you find another Haldex control module. Need to check by car.

There is no diagnostic equipment. We do not know if the oil pump is faulty.

What to do? We connect the control module to a group of 8 pin contacts.

The control module has an output with 2 pins to which the oil pump is connected.

Connect a 12 volt lamp to this output.

Turn on the car engine. Is the lamp shining? The control module is operational.

Does the lamp not shine? We are looking for a reason.

About Me.

I am repairing all-wheel drive with a Haldex clutch.

These are cars Volvo cars, Land Rover, Audi VW Seat Skoda, Ford, Opel, SAAB

Maintenance, diagnostics, troubleshooting and repair.

You can order just a consultation, individual spare parts or ready-made units.

We ship to any country by land or air.

email  autocarmd@gmail.com  WhatsApp +40730117997