VOLVO
ECM-258D - Front heated oxygen sensor (HO2S), bank 2. Signal too low
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
2 modelsS80 (1999–2006), XC90 (2003–)
Show models by year and engine (2)
What does this fault code mean?
The engine control module (ECM) detects that the signal wires to the oxygen sensor on bank 2 are shorted to ground, which shows up as a signal that is too low. The code is then set.
Possible causes
- Signal wires shorted to ground
- Damaged oxygen sensor on bank 2
What you can do
- 1Clear the code, road test the car and then check whether it comes back
- 2Look at the connector at the lambda sensor: it should be seated firmly and free from moisture and oxide. Avoid rust solvent spray and grease
- 3With the control module disconnected, use a multimeter to check that the signal wires have no contact with ground (chassis)
- 4Look for chafed and pinched spots on the wires, especially where they may have rubbed against an edge
- 5If the wires are intact but the fault remains, have a workshop check or replace the lambda sensor
Symptoms you may notice1
- Malfunction indicator lamp (MIL) on
General guidance for car owners. Diagnosis on the car can point to a different cause.