VOLVO
LPG-0172 - Fuel / air mixture. Rich
System
Liquid Petroleum Gas (LPG)
Volvo models this fault code applies to
Applies to the following models:
2 modelsS40 (1996–2004), V40 (1996–2004)
Show models by year and engine (2)
What does this fault code mean?
The LPG control module reads the front heated oxygen sensor while the car runs on gas. The sensor should switch evenly around the correct air-fuel ratio, and the code is set when it sticks at the rich limit for a longer time, meaning the fuel mixture is too rich.
Possible causes
- Faulty vacuum hose linking the intake to the pressure regulator
- Incorrect gas pressure
- Fault in the wiring
- Defective fuel shut-off valve
- Defective pressure regulator
- Defective fuel rail
What you can do
- 1Make sure there is enough gas in the tank before you carry out the lambda check
- 2Make sure the hose running from the intake to the pressure regulator is fitted properly and that fittings and hoses are sealed
- 3Have a workshop check the gas pressure
- 4Have a workshop check the fuel rail and the function of the fuel shut-off valve
- 5Look for damage and chafing on the wiring and check that it has no breaks or short circuits
- 6If you have diagnostic equipment, run the car on gas and see whether the lambda value swings evenly; then erase the code and road test the car
Symptoms you may notice1
- The engine does not run on gas
What the fault can affect1
- The car switches over to gasoline power automatically
General guidance for car owners. Diagnosis on the car can point to a different cause.