VOLVO
ECM-8420 - Sensor supply 2. Signal too low
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:
8 modelsC30 (2007–2013), C70 (2006–2013), S40 (2004–2013), S60 (2001–2009), V50 (2004–2013), V70 (2000–2008), V70 XC / XC70 (2001–2007), XC90 (2003–)
Show models by year and engine (23)
- Volvo C30 (2007–2013)2007Engine D5244T8, D5244T9 only
- Volvo C30 (2007–2013)2008, 2010Engine D5244T13, D5244T8, D5244T9 only
- Volvo C30 (2007–2013)2009Engine D4164T, D5244T13, D5244T8, D5244T9 only
- Volvo C70 (2006–2013)2007Engine D5244T8, D5244T9 only
- Volvo C70 (2006–2013)2008–2010Engine D5244T13, D5244T8, D5244T9 only
- Volvo S40 (2004–2013)2006Engine D5244T8 only
- Volvo S40 (2004–2013)2007Engine D5244T8, D5244T9 only
- Volvo S40 (2004–2013)2008, 2010Engine D5244T13, D5244T8, D5244T9 only
- Volvo S40 (2004–2013)2009Engine D4164T, D5244T13, D5244T8, D5244T9 only
- Volvo S60 (2001–2009)2006Engine D5244T4, D5244T5, D5244T6, D5244T7 only
- Volvo S60 (2001–2009)2007–2009Engine D5244T4, D5244T5, D5244T7 only
- Volvo V50 (2004–2013)2006Engine D5244T8 only
- Volvo V50 (2004–2013)2007Engine D5244T8, D5244T9 only
- Volvo V50 (2004–2013)2008, 2010Engine D5244T13, D5244T8, D5244T9 only
- Volvo V50 (2004–2013)2009Engine D4164T, D5244T13, D5244T8, D5244T9 only
- Volvo V70 (2000–2008)2006Engine D5244T4, D5244T5, D5244T6, D5244T7 only
- Volvo V70 (2000–2008)2007Engine D5244T4, D5244T5, D5244T7 only
- Volvo V70 (2000–2008)2008Engine D5244T5, D5244T7 only
- Volvo V70 XC / XC70 (2001–2007)2006–2007Engine D5244T4 only
- Volvo XC90 (2003–)2006–2007Engine D5244T4 only
- Volvo XC90 (2003–)2008–2010Engine D5244T4, D5244T5 only
- Volvo XC90 (2003–)2011Engine D5244T18, D5244T4, D5244T5 only
- Volvo XC90 (2003–)2012All engines except: B5254T2, B6324S5
What does this fault code mean?
The engine control module (ECM) monitors the supply voltage to the engine sensors and sets the code when it is too low or too high. The check runs with the ignition on. This variant applies to a supply that is too low, which can come from an open circuit, poor contact or a short to ground in the supply wire.
Possible causes
- Loose connection, contact resistance or oxidation in the connections
- Open circuit in the voltage supply wire
- Short to ground in the voltage supply wire
What you can do
- 1Read the code, clear it and check that it is not active after the road test
- 2Check the sensor supply connectors for loose fit, contact resistance and oxidation
- 3Check the supply wire for an open circuit, and use a multimeter to confirm it has no contact with ground (the body)
- 4If you have diagnostic equipment, read the sensor supply voltage in live data with the ignition on and see whether it is too low
- 5If the fault remains after these checks, have a workshop trace the sensors and the control module further
Symptoms you may notice1
- No noticeable symptoms for the driver
General guidance for car owners. Diagnosis on the car can point to a different cause.