Hello - first time posting on here. I have been following along with some other blogs that have the same or similar issues, but their solutions have not worked for me. So I am posting here hoping for some new ideas/suggestions.

1997 (early) Jaguar XK8 4.0 Convertible.

- I am having A/C issues. The onboard diagnostic brought up error codes 23 and 24.
- I checked the wiring from the A/C relay to the compressor - the wire was broken - so I have run a new piece of wire from the relay to the compressor. You can here it 'click' when it is jumped, leading me to believe this is now fixed.
- Code 24 disappeared. Code 23 Remains.
- Code 23 ... The A/C place near me said that the gas/pressure is not an issue. The problem is electrical.
- I jumped the pins at the 6 pin connector (1 blank pin) that connects to the pressure switch. I could get the fans to switch on, tested continuity, and 12v on three of the five pins. So I assumed it was a faulty switch.
- I replaced the pressure switch - code 23 remains - and the CCM/ECM refuses to engage to compressor.
- I have tried to usual code clearing methods - both on the climate control panel and by disconnecting the battery.

Any suggestions would be greatly appreciated. I feel I have reached the limits of both skill and patience!

Thank you.

 

Have you tried clearing the code with an OBD scanner?

Was does a 23 actually mean?

Richard

 

Hi Richard,

Thanks for your reply. Code 23 only comes up on the climate control panel, not on the OBDII. Pressing the AUTO and RECIRC buttons and then turning the key into position 2 brings up the code on the small digital screen. Code 23 is: Refrigerant pressure switch malfunction or refrigerant pressure low. It is a mystery - because the switch has just been replaced and the refrigerant is full (according to the AC place!).

Thanks,

Ben

 

I'd be inclined to get the pressure checked again at a different place before going down a rabbit hole of diagnosis.

 

I see. I would get hold of the wiring diagram and check all the wires that are connected to the switch, and are not live, through to the other end of each wire and check for continuity. If any of the wires are grounded, check on the diagram that they are supposed to be grounded. It might be another broken wire which can be bypassed.

Richard

 

From the WS manual:

"
Pressure (Bitron) switch

Located in the discharge pipe.

• Provides a signal, via the A/CCM, to the ECM, to disengage the compressor clutch should the refrigerant pressure be < 2 bar or > 30 bar.
• Provides a hard-wired signal to the ECM, to switch the cooling fans to HIGH speed at 22 bar rising pressure and to LOW speed at 17,5 bar falling pressure.
• Provides a hard-wired signal to the ECM, to switch the radiator cooling fans to LOW speed at 12 bar rising pressure and to switch the fans OFF at 8 bar falling pressure

"

...and the relevant circuit from the Electrical Guide:



So the blue/black connection should be at ground potential always, subject to the A/C system pressure being between the limits above.

The white/blue and yellow/white connections should ground in accordance with the settings above.

The '97 compressor has an extra, separate, connector for the 'compressor lock' sensor. Its wire colours are slate/black & black/white. Check that it's OK and in place.

 

Thank you all for your replies.

- Two separate places have confirmed the gas system is charged.
- I have checked the plug socket to the pressure switch. 3 wires have a 12v signal, 2 have continuity to ground. This seems to match the chart?
- I jumped the socket with a bridge and the fans engaged automatically (as I believe they should), the computer still showed code 23 though, so no cold air.
- I checked the compressor was engaging by jumping it from the relay. It engages fine and starts spinning up (I only did this for a few seconds for safety).
- I replaced the pressure switch.
- Code 23 persists after a battery reset!
- Am I correct in thinking that if the ECM > switch is okay and the relay > compressor is okay - then the issue must be somewhere from the ECM to relay?

Any guidance would be most appreciated. It is 28c here in Brunei today and I could do with a bit of cold air! The roof hydraulic hose has sprung a leak, so that can't go down at the moment, but that is a problem for another day!

Thanks,

Ben

 

Hi XK8 Brunei,

To read these codes via OBDII requires a scan tool that can read the proprietary Jaguar Body DTCs, which have a B-prefix. There are also Chassis (C-) and Network (U-) codes, but generic OBDII scanners can only read the Powertrain (P-) codes.

The DTC Summaries manual gives more detailed definitions and possible causes of these codes. As you can see, the HVAC panel codes 23 and 24 can each be triggered by two different OBD codes, so if you could access a scan tool capable of reading the B-prefix DTCs it would help focus your diagnostic process:





You can download the wiring schematics at this link:

Jaguar X100 Electrical Guide 1997

Cheers,

Don

 

What can you hear click - the clutch relay or the clutch itself?