Dear Forum,
It would appear that I have a short circuit to ground on my front left side Air Shock? DTC C2304 and a yellow CATS Fault showing with an annoying 'ding' from time to time! Suspension feels fine? My code reader shows Damper Firm - Error.....Yes?
Please see attached pinpoint test. The voltage (less than 3 volts) is okay, but I just cannot seem to get any response to a resistance reading? My multimeter just sits there showing 1? I have it set on 20,000 ohms? Same with the right side connector? If I disconnect them I get open circuit DTC's (C1419, C1424), which then clear as I reconnect them?
What am I doing wrong, please? For example, do I need to try to test the resistance with the connector actually connected, or should I be able to get a reading with it disconnected? Should the ignition be on or off?

 

Do not recall the numbers but after the suspension warning light..

Reader pointed me to the front left air shock, causing the issue.

Believe it was open circuit, or loss of ground,

I found the plug on the height sensors clip, broken, & had worked loose.

Pushed it back on, all was well.

Hope your fix is as simple,

 

Hello Wingrider, good to hear from you.
No, I think the problem is the actual front left hand shock (not the air part). I have already had to replace the front right shock and in an earlier post I attached pics of the red 'dust' this left front shock was throwing out; 165,000 kilometers, so no complaints!
Having said all this, I still do not know why I am failing to achieve the resistance pinpoint test on either front shock? I hate auto electrics and yet given another 10 years or so and virtually all car maintenance will be auto electrics!!!!
I imagine the solenoid in the shock has failed and it has defaulted to hard. If so, then it is going to stay hard until I have saved up enough pennies to replace it! I will just have to turn the music up so the occasional 'beep' the yellow CATS Fault light gives out is drowned!!
I have to say that I really have not noticed any difference in the ride, but (obviously) I would welcome any comments or suggestions regarding other possible causes before going to this expense!

 

How was your trip??? Good i hope, glad to hear from you as well;

They do require rebuilding or replacement around a hundred thousand miles.

Too bad about your location, as $550, handled rebuilding two front shocks, including the shipping both ways.

Keeping the cats system intact, unlike the Arnotts on the other Jaguar, which are very nice shocks as well.

 

Ign. off for resistance check.

disconnect plug

Place meter on ohms say 100, touch meter probes together-meter should go to zero.

Place one probe on pin on plug which has wr (white /red) wire connected and touch earth. eg strut nut which is bare of paint.

If meter goes off scale bring reading on scale until you get a reading.

If resistance is <10 000 ohms then you have a short to earth ON THAT WIRE.

 

Thanks Meirion1!

 

Yes, thanks from me too, useful to know.

 

Hello Meirion1,
I am still unable to get an ohm reading; both fronts just stay showing a 1 (presumably no reading)....?
However, if I switch on the ignition, on both fronts I get 12 volts! If the pinpoints point to a (potential) break in either the power or ground wire, would a continuity test help? If I put a probe in each of the two connector females when switched to continuity, will that confirm or deny a short, please? Does the other wire (the non-tested one in the pinpoint test) return info to the ECU? Is the tested wire supply from ECU and the other return to ECU?
Please, what do I try next?
Thank you.....

P.S. I can detect absolutely no change to the feel or behavior of my suspension?

 

Today there was no CATS System Fault message when I switched on my ignition or when my car started; then, as soon as I put her into Drive, up it came?

 

What does your meter show when you set it to ohms and connect both probes to each other?

 

Meirion1, thank you for getting back to me.

I figured that my multimeter must be faulty, so I have invested in a spanking new Fluke!

On auto range my ohm readings are 25 (000 I imagine) and my volts are 0.55.
I bet you are going to instruct me to test the back shocks now, aren't you?

Meirion1, before I pull my boot apart, is there a way to test the pins in the front shock tops for (example) Damper solenoid failure that could cause a C2304?

 

Good question, avoid as much unnecessary disassembly as possible

 

"On auto range my ohm readings are 25 (000 I imagine) and my volts are 0.55"

You should get zero-without that you can't go any further.

 

Hi EsRay,

Just to clarify your questions via PM, you probably do not have a problem with your damper actuators. The fact that you get the open circuit DTCs when you disconnect the ECATS connectors suggests the actuator coils are intact and providing the expected impedance or resistance to the ASU.

Forgive me if I repeat some of the information already provided by meirion1 and others - I'm going to think out loud:

C2304 indicates a short to ground in the voltage supply, which is the White/Red wire that connects the damper actuator to the Air Suspension Control Module (ASM). Here are the definition and possible causes from the DTC Summaries manual:




According to the pinpoint tests, a "short" to ground is resistance less than 10,000 ohms. So to test this, turn your meter on and set it to the resistance range just greater than 10,000 ohms (e.g. 20,000 ohms). Confirm the meter is working by touching the leads together: the display should read a very low resistance close to zero ohms. This is the DC resistance of your test leads.

Disconnect the ECATS connector from the front left air spring/damper and connect the positive lead of your meter to the harness connector pin connected to the White/Red wire. Connect the other meter lead to a good unpainted chassis groud such as the air spring stud meirion1 mentioned. Observe the reading on the meter. If it reads 1, that means the resistance exceeds the range to which the meter is set. Increase the range upward and see if you get a reading greater than 10,000 ohms. If you get no reading even with the meter set to 1 megohm, return the range setting to the one just above 10,000 ohms. Now, while watching the meter, flex and manipulate the wiring harness at every point along its length as far as you can follow it to where it connects to a main harness. If the meter jumps to a lower resistance when you flex the harness at a certain point, you have found the short.

If I understand the above Possible Causes, you should repeat the tests on the right hand side on the White/Blue wire, the left rear on the White/Green wire, and the right rear on the White/Black wire. The pin numbers in the Possible Causes are actually at the ASM connector, not the damper ECATS connectors.

I can't recall - have you tried clearing the DTC to see if it recurs?

Looking forward to your next report.

Cheers,

Don

 

Hello Meirion1,
With my new multimeter I get zeros when I touch the probes together.

On auto range my ohm readings are 25 (000 I imagine) and my volts are 0.55.

 

Thanks Don, I have tried clearing the DTC's; the open circuits clear when I plug the connectors back in, but C2304 will not budge?

I get 25k ohms and 0.55 volts at the front shocks with my new multimeter; so, I guess my next step is to pull my boot apart to check the rear shocks.....Even though I think the DTC is spurious because my suspension does not feel any different. My understanding is that it should default to 'hard' if CATS is faulty....(Why hard was chosen as the default eludes my understanding), but in any event, my suspension does not feel 'hard'?

 

After further studying the Possible Causes and the wiring schematics I edited my previous post to include the suggestion that you also test the front right and the rears. If that doesn't turn up the short, you might try testing from the ASM connector, since the pin designations given in the DTC Possible Causes are for that connector rather than the damper ECATS connectors. Measuring from the damper end includes the ASM in your measurement, measuring from the ASM connector would include the damper actuator coils.

The term Jaguar uses isn't "hard" but "firm," as opposed to "soft." The reason the default setting is firm is probably because it provides the greatest control of the vehicle, and therefore assures the greatest safety under all operating conditions.

Cheers,

Don

 

Thanks Don,

I hear what you are saying re: Soft & Firm, but since our cars are in Soft until we aggressively corner, brake or accelerate, it seems to me that Soft would be a better default? I am pretty certain all those on this forum who have experienced a constant Firm might agree with me

On auto range my readings for the backs are 1.7 ohms? (I do not really understand what relationship auto ranged 1.7 ohms has to 10,000 ohms but it appears to be considerably less)? and zero volts on both rears? Wiring looks immaculate?

How do I access the ASM, please?
Do I now need to strip out my back seat and add it to my pile from the boot, please?

 

When you set your meter on autoranging, the units it selects may be different than the units it selects if you set a specific range. For example, 1.7 ohms is equal to 0.0017 kilohms or 0.0000017 megohms or 1700 milliohms or 1,700,000 microhms. For any measurement we have to pay attention to the units being displayed.

If your measurement of 1.7 was truly in ohms, and was measured between the supply wires to your rear ECATS connectors and ground, then it is clearly far less than 10,000 ohms and is the cause of your C2304 DTC.

To access the ASM you do have to remove the rear seat lower cushion and back cushion. The ASM is mounted toward the right side behind the rear seat back.

Cheers,

Don

 

Thanks again Don,

Could a poor Ground be causing this? I am picturing a poor Ground failing to complete the circuit so that there is little resistance and no current flow? (Just thought I would ask before removing my rear seat, which includes the rear entertainment centre in the armrest)!

Please, is this the Ground Point for the ASM?