VOLVO
ECM-520C - Air conditioning (A/C) pressure sensor. Signal too high
System
Engine Control Module (ECM)
Volvo models this fault code applies to
This fault code has different meanings depending on model, model year or engine. Select the meaning that applies to your car.
Applies to the following models:
5 modelsS60 (2001–2009), S80 (1999–2006), V70 (2000–2008), V70 XC / XC70 (2001–2007), XC90 (2003–)
Show models by year and engine (14)
- Volvo S60 (2001–2009)2005–2006Engine B5204T5, B5244T4, B5244T5, B5254T2, B5254T4 only
- Volvo S60 (2001–2009)2007Engine B5204T5, B5244T5, B5254T2, B5254T4 only
- Volvo S60 (2001–2009)2008–2009Engine B5204T5, B5244T5, B5254T2 only
- Volvo S80 (1999–2006)2005–2006Engine B5204T5, B5244T4, B5254T2, B6294S2, B6294T only
- Volvo V70 (2000–2008)2005Engine B5204T5, B5244T4, B5244T5, B5254T2, B5254T4 only
- Volvo V70 (2000–2008)2006–2007Engine B5204T5, B5244T5, B5254T2, B5254T4 only
- Volvo V70 (2000–2008)2008Engine B5254T2 only
- Volvo V70 XC / XC70 (2001–2007)2005All engines except: D5244T
- Volvo V70 XC / XC70 (2001–2007)2006Engine B5244T4, B5254T2 only
- Volvo V70 XC / XC70 (2001–2007)2007Engine B5254T2 only
- Volvo XC90 (2003–)2005–2006Engine B5254T2, B6294T only
- Volvo XC90 (2003–)2007–2012Engine B5254T2 only
- Volvo XC90 (2003–)2013–2014Engine B5254T9 only
- Volvo XC90 (2003–)2015
What does this fault code mean?
The engine control module (ECM) receives an A/C pressure sensor signal above the sensor's normal operating range. The code is set when the engine runs and A/C control is active, and the air conditioning does not work while the fault is present.
Possible causes
- Signal wire shorted to supply voltage
- Open circuit in the supply to the sensor
- Open circuit in the ground lead
- Damaged A/C pressure sensor
What you can do
- 1Read and note the code, clear it and road test with the A/C switched on to see whether it returns
- 2Check that the A/C pressure sensor connector is secure and free from corrosion
- 3Look for chafed, pinched or loose wiring between the sensor and the engine control module
- 4With a multimeter, check that the signal wire has no contact with supply voltage and that the supply and ground leads are not broken
- 5If you have a diagnostic tool, follow the A/C pressure in live data with the A/C on and see whether it reads unrealistically high
- 6If the fault returns after these checks, have a workshop test or replace the sensor
Symptoms you may notice1
- The air conditioning system does not work
General guidance for car owners. Diagnosis on the car can point to a different cause.