Is anyone any good with air suspension faults ? I have an EASC fitted to my 2002 RR and am getting an air suspension fault and HDC inactive.

When I go into the EAS menu it says I have '50 Can Defect' fault. It resets no problem but will come into fault again within a day.

I know it is related to some work that I have recently had done, which was my front driveshaft boot replacement. I had it done at my local garage as my Indy couldn't fit me in, in time and I needed to tow with the car and didn't want to when it had lost its grease. I locked the suspension before they worked on it, but it would appear somthing has been damaged, mis aligned.

Someone did suggest disconnecting battery and reseting the stearing calibration which I have done with no joy in fixing fault.

Please help ?? What does Can refer to ??

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CAN - Controller Area Network

Something is interfering with your can-bus, could it be your EASC? Can you disconnect it to rule it out? 

It is pretty difficult to take out, what is can bus ?

CAN stands for Control Area Network. It is a form of multiplexed wiring designed by Bosch and allows the linking of a number of control systems together, normally in a vehicle, so that they can share information. In the past it would have been necessary to have at least one wire for every signal on a vehicle making wiring looms bulky and expensive. CAN bus multiplexing allows a large number of signals to be transferred digitally using only a pair of twisted wires.

Sharing of information on a CAN bus also reduces the number of sensors that are needed. For example the engine controller has its own sensor to monitor coolant temperature. Using CAN it can share the temperature reading so that the information is available to any other systems on the car that are interested. One such system might be the instrument cluster, which would use the information to drive its temperature gauge.

CAN bus has been used in road cars for over 10 years. Starting at first with the high-end prestige vehicles, it is now commonplace in virtually all European cars and is becoming more popular in the US and Japan.

While CAN bus is a very efficient way of connecting control units in a vehicle, it does present a problem to anyone fitting aftermarket equipment to a vehicle. This is because signals such as vehicle speed or RPM that used to be sent on separate wires can no longer be ‘tapped’ into directly.

The idea behind CAN is simple.

Instead of connecting everything to a central control unit through a main wiring harness, each component in the network has its own processing and communication capabilities, with one data channel connecting all units.

In automotive CAN applications, the instrument panel, power windows, body accessories and even many sensors and actuators all have their own individual mini-control unit. All the units, called ‘nodes’, communicate with each other through a single pair of wires. These are twisted together to ensure minimum interference and is known as the ‘data bus’.

All the data on the bus is addressed to a specific node or group of nodes by function, not location. The relevant nodes respond to a particular pre-programmed protocol. For example, the vehicle speed sensor will put its data on the bus, and every other control unit that needs vehicle speed information will receive it directly without having to go to the PCM (Pulse Code Modulator ) for a VSS ( Vehicle Speed Sensor ) signal.

Because there are multiple nodes sharing a single bus, every date package includes a priority code. This will ensure, for instance, that if the ABS control unit and the lighting unit both send a message to the PCM, the critical ABS system message gets to go first.

CAN technology will significantly reduce the number of connector pins and wires in the vehicle. With extra ‘blank’ connectors built into the network loop, or with a splice kit for adding connectors, nodes can be added on the production line (or even aftermarket) without running a new wiring harness. However, designers have built in more than one network on the vehicle, linked by ‘gateways’ where appropriate. The mission-critical nodes will be linked on a high-speed Class C network that can operate in virtual real-time. Less critical items, such as the instrument panel, lighting systems will use a slower Class B network, and ‘occasionally used’ body accessories, such as power windows are likely to use a Class A network. 

dan_uk_1984 wrote:

CAN - Controller Area Network

Something is interfering with your can-bus, could it be your EASC? Can you disconnect it to rule it out?

The EASC is inactive and more or less just along for the ride when it has not been activated (and activating the EASC requires having the vehicle in park with the motor running and pressing the 'resume' button on the cruise control 10 sec.). It is highly improbable that the EASC is sending erroneous signals - and that these signals are disturbing only the EAS ECU (and not one of the many other items on the CAN).

That said, Dan is right. Something is likely disturbing comms between the EAS ECU and the CAN. How did you connect the EASC's wiring to the original harness? Did you clip the original CAN wires and reconnect them with the EASC harness' wires? Can you recheck the connections and the insulation at your connections? This is why the instructions with the EASC recommend stripping a section in the middle of the wire without clipping through it and attaching the EASC wires to the stripped section. See pics below for my method of connection.

Unplugging the EASC as Dan suggested will give you 100% assurance that this is not the cause of your probs, but my money is on a bad connection (or, possibly, an unrelated issue).

I've passed your post on to Christian from GAP Diagnostic. He'll either post his ideas here directly or pass the info back to me and I'll post.



Here is how I connected my EASC. The problem is, soldering is not really recommended for use in automotive applications (for various reasons). The crimp connectors I used are available as 'C' connectors but as I didn't have these I used regular crimp-on terminal ends and clipped off the terminal.

Connecting power and ground. You can see the brown ground stripped w/o being clipped and the thick red (OEM) wire with the thin red (EASC) wire crimped on. Connections are staggered to eliminate any possibility of a short circuit. You will need proper crimping pliers for uninsulated terminals to do this.


Individually insulated:


And the harness closed back up and ready to be plugged in (disconnect battery before unplugging the ECU and follow the battery disconnection procedure in the RAVE!):


Admin note: this post has had its images recovered from a money grabbing photo hosting site and reinstated  
RRC 2Dr, RRC 4Dr,
P38, and 2 L322s
(wife thinks I'm nuts - prob right, too)

Thanks Steve and Dan for your replies, I have a better understanding of the system now, yet another complexity to the modern vehicle.

I fitted the EASC as per the instructions stripping back the insulation, gapping the wires and twisting them up tight before insulating again. I would be very surprised if it is the EASC. I have been e mailing Christian who has recommended looking at the ABS sensor on the side that has had the work, so will do this tomorrow, because if this is using the same wiring then the ABS will take priority and throw a fault on the Can.

Fingers crossed and I will get back when it is resolved.

Thanks....................Adam

lol, that's only the can-bus! There is still the K-Bus and the i-Bus yet!