SL-Class (R230) 2003 -- 2012: Discussion on the SL500, SL550, SL600

SL/R230: How do I replace Refrigerant pressure and temperature sensor 1???

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Old Sep 15, 2020 | 03:51 PM
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Question How do I replace Refrigerant pressure and temperature sensor 1???

How do I replace Refrigerant pressure and temperature sensor 1???
Here are the DTCs. Is sensor 1 the previously purchased For 2003-2006 Mercedes SL500 A/C Refrigerant Temperature Sensor 74425WH? Above the dryer? (See link below) If so, can I just unscrew the old one, and screw in the new one? Or will unscrewing the old one purge all of the refrigerant?
09152020 from Diaglink:
Read Codes
B1337-002
Stored&Current
B12/2 (Refrigerant pressure and temperature sensor 1) ( Refrigerant temperature ):The component is faulty or the lead has Open circuit.
B1338-002
Stored&Current
B12/2 (Refrigerant pressure and temperature sensor 1) ( Refrigerant pressure ):The component is faulty or the lead has Open circuit.
B1341 Stored&Current
Fault in communication with component H3 (Alarm signal horn).
Event memory
B1059-001 Current
Fault in CAN communication with control unit Driver signal acquisition and actuation module.





https://www.ebay.com/itm/For-2003-20...8AAOSwb91dZn6n

For 2003-2006 Mercedes SL500 A/C Refrigerant Temperature Sensor 74425WH 2004 2005

Seller: autopartsgeek
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Old Sep 16, 2020 | 02:47 PM
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I pulled a reading of 3698 psi at the sensor:
182 B12/2 (Refrigerant pressure 255.0 bar
and temperature sensor) Pressure value

Does this mean the Refrigerant pressure and temperature sensor is faulty?

See the codes and event memory below:
Read Codes
B1337-002 Stored&Current
B12/2 (Refrigerant pressure and temperature sensor 1) ( Refrigerant temperature ):The component is faulty or the lead has Open circuit.
​​​​​​​B1338-002 Stored&Current
B12/2 (Refrigerant pressure and temperature sensor 1) ( Refrigerant pressure ):The component is faulty or the lead has Open circuit.
B1341 Stored&Current
Fault in communication with component H3 (Alarm signal horn).


Event memory
B1059-001 Stored&Current
Fault in CAN communication with control unit Driver signal acquisition and actuation module.
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Old Sep 16, 2020 | 04:02 PM
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Sounds like the pressure sensor could be faulty to me. You might hook up a known good sensor to the electrical, and see if the value is zero PSI, before you evacuate and recharge the AC system.

However, the B1059 sounds like this might be a communication issue with the SAM. See this thread for input: https://www.benzworld.org/threads/ai...o%20re%2Dcheck.

Your alarm siren (H3 in the left front fender well) is also faulty, which is common. You can replace it with just about any siren from many models, but it will fail again. See lots of threads on that issue.
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Old Sep 17, 2020 | 12:56 PM
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Thanks for the help guys!

Hydraulic oil may have fowled up the Refrigerant pressure and temperature sensor.

I spoke with a great mechanic yesterday. I showed him the codes and Diaglink data. I explained to him that I added 2 cans of refrigerant. He asked if I had oil in the sensor. I told him I cleaned hydraulic fluid out of the sensor and connector, got the compressor working, then added refrigerant. He confirmed that the sensor I ordered is the right one. He thinks the hydraulic oil caused the problem; and I compounded the problem by adding refrigerant after I cleaned oil out of the sensor and connector.

He proposed to evacuate the refrigerant, clean the sensor, and fill the system properly. I will wait and check readings with the new sensor connected to the wiring connector, and not installed on the dryer line; and see if the pressure reads zero, check the remaining codes, then try his solution. I may not even need the new sensor. I cleaned the sensor and connector again, and removed the wicking cloth tape around the wires. So, he may just need to correct the refrigerant level.

Some of my old readings 6 months ago show 9 bars pressure. Today it shows 555 bars pressure. I probably overfilled it. But that super high reading seems like the sensor is messed up. About 6 months ago I had hydraulic fluid reservoir burp up quarts several times before I fixed the suspension. Fluid wicks its way up cloth tape into sensors.

The sensor won’t arrive until next week. If the diagnosis and solution are not as described here, I will let you know.
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Old Apr 25, 2022 | 11:52 AM
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Originally Posted by kbob999
Sounds like the pressure sensor could be faulty to me. You might hook up a known good sensor to the electrical, and see if the value is zero PSI, before you evacuate and recharge the AC system.

However, the B1059 sounds like this might be a communication issue with the SAM. See this thread for input: https://www.benzworld.org/threads/ai...o%20re%2Dcheck.

Your alarm siren (H3 in the left front fender well) is also faulty, which is common. You can replace it with just about any siren from many models, but it will fail again. See lots of threads on that issue.
bumping an older thread as I have this same issue with a 2004 SL55 that the AC no longer blows cold and shows low on refrigerant. I also have the code showing B1059 CAN/communication on my icarsoft diagnostic tool and am trying to understand where that module is and if it needs replacing?

this just happened following my coilover conversion where my indy mechanic also coded out the ABC function so I have zero malfunction alerts on the dash and the ABC button doesnt illuminate (1 or 2 red dots dont show up) anymore... am wondering if that ABC module he coded out has anything to do with this? likely not but thought i would mention... any help would be greatly appreciated. thanks
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