VOLVO
ECM-436B - Leak diagnostic unit. Signal missing
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 monitors the current drawn by the pump in the leak diagnostic unit during the reference phase. If the current varies too much during that phase, the fault code is set. The fault can come from poor contact, a blocked hose between the filter and the unit, or a damaged leak diagnostic unit.
Possible causes
- Contact resistance in the connections
- Filter-to-unit hose is blocked
- Damaged leak diagnostic unit
What you can do
- 1Have a workshop confirm that the engine control module software is current on cars of model year 2003 to 2008
- 2Have you got a diagnostic tool: read the pump current in live data during the reference phase and check whether it swings a lot
- 3Check the connector to the leak diagnostic unit for contact resistance and oxidation
- 4Look for kinked or clogged lines running from the filter to the unit
- 5Run a new quick test after the repairs and check that it no longer shows a fault
- 6Have a workshop replace the leak diagnostic unit if the fault remains after these checks
Symptoms you may notice1
- Malfunction indicator lamp (MIL) is on
What the fault can affect1
- The leak diagnostic is disabled
General guidance for car owners. Diagnosis on the car can point to a different cause.