Assalamu'alaikum Warohmatullohi Wabarokatuh, welcome to the "Biggy Feri" youtube channel. On the volvo truck fm 400, there is an "Over Air Pressure" problem on the "Air Brake System". So, we can look at the "pressure gauge" for tank 1 and tank 2. The pressure in the "Air Brake System" exceeds its normal limit, which is about 8.5 bar or which is marked with a green indicator. Then, on the monitor display there is a symbol like this, this indicates a problem with the "Air Dryer System". In the diagnostic menu (Vehicle System) there is error code information regarding "Regeneration Status", "Mechanical Fault" and the status is still active. Then we do "Test Gauge" to find out if the gauge is still normal or not. Ok friends, in this video, I will explain the electrical path (Wiring Diagram) of the "Air Dryer". In order to make it easier for friends when checking when there is a problem with the "Air Dryer System", especially problems with the electrical (wiring harness).
So, when the ignition is still in the OFF position, then the supply voltage for the stand-by "Air Dryer" on "Relay K02". For "Relay K02" it gets a voltage supply directly from the battery. Then, when we position the ignition switch ON, the "Relay K02" will be active and the supply voltage goes to the fuse on the "Fuse Box". Next, we check the "Fuse Box", we look for the fuse used for the "Air Dryer". The fuse used for the "Air Dryer" is number 6, with a capacity of 5 Ampere. Then, we remove the fuse and we check the "Fuse Test".
To make sure the fuse is still good or not. If the fuse is still good, then we put it back in position. From fuse number 6 earlier, the voltage supply line goes to the XL cable socket on pin number 3. For the XL cable socket it is located at the bottom of the "Fuse Box" or behind it from the "Fuse Box". So to see it, we first remove the fastening bolt from the "Fuse Box", then we reverse its position. So, for this XL cable socket it is white like this, then we look for pin number 3. For pin number 3, the cable is black. Then, from the XL cable socket pin number 3, the voltage supply line goes to the CB cable socket on pin number 3. The CB cable socket is located on the front left of the cab (vehicle).
So, for the CB cable socket or the blue "Air Dryer" cable socket like this. There are 3 wires in this CB cable socket. The black cable is the voltage supply cable from fuse number 6 or from the XL cable socket pin number 3. For the green/white cable is the cable from solenoid regeneration that goes to the VECU on the PB pin number 1. Then, for the blue cable/ white is the cable from the "Compressor Control" (Unloading) solenoid that goes to the VECU on the PB pin number 4.
Ok friends, here is the VECU on the Volvo truck. The location of the VECU is at the bottom of the "Fuse Box". So, when you have opened or removed the "Fuse Box", this VECU will be visible. So, for the PB cable socket (connector) on the VECU is the blue one. This VECU serves to activate the ground (negative) for the solenoid on the "Air Dryer", when the conditions are met. So that the regeneration process on the "Air Dryer" and "Unloading" on the "Air Compressor" can occur.
Next, we do a voltage check on the black wire. This cable is located in the CB cable socket pin number 3. Here we use "Multitester" and we select the selector in the Volt DC position. The results of this inspection, the supply voltage from fuse number 6 leading to the CB cable socket is still good, which is in accordance with the battery voltage. Ok friends, here is the cable socket (connector) on the "Air Dryer" solenoid. With this condition, the "Pressure too high on the air brake system" problem could be caused by the cable socket (connector). Next, we check the voltage on the black wire. So, for the black cable, it is the voltage supply cable from fuse number 6. The results of this check, the voltage on the black cable is still good, which is in accordance with the voltage on the battery.
Ok friends, then we remove the CB cable socket (connector), then we check the green/white cable and the blue/white cable. So, we do this check between the CB cable socket and the cable socket on the "Air Dryer" solenoid. We use the "Multitester" and turn the selector in the Ohm position, to make sure the cable is still good or something is broken. First, we check the green/white cable. The results of this check, the green/white cable is still good or still connected. Then, we also check the blue/white cable. The results of this inspection, the blue/white cable is also still good. Because the results of the inspection are still all good, then we can make repairs to this cable socket (connector) or we can replace it with a new connector if there is one.
Ok friends, after we do the inspection and repair, then we do the experiment. And we'll see "Pressure Gauge" for tank 1 (front tank) and tank 2 (rear tank), whether it's still a problem or is it normal. Ok friends, after we did the inspection and repair, the result is that the air pressure in tank 1 (front tank) and tank 2 (rear tank) is normal. So, that's the electrical line (wiring harness) on the "Air Dryer". Hopefully it can help friends when there is a problem with the "Air Dryer", especially when there is a "Pressure too high on the air brake system" problem on a Volvo truck.
So many videos from me, hopefully useful, thank you, Wassalamu'alaikum Warohmatullohi Wabarokatuh..
