Charger Forums banner
1 - 1 of 1 Posts

·
Registered
Joined
·
3,554 Posts
The PCM (powertrain control module) uses the upstream O2 sensor signal to determine the correct fuel trim. If the O2 sensor indicates a lean condition the PCM will increase the pulse-width of the injectors to add fuel. If the O2 sensor indicates a rich condition the PCM will decrease the pulse-width of the injectors to reduce fuel. The other components used to manage the AFR (air fuel ratio) are the MAP (manifold absolute pressure) sensor and the EVAP Purge solenoid. The other item to check is the fuel pressure to see if fuel pressure is too high (bad fuel pressure regulator). Fuel pressure should be constant at 58 psi (± 5 psi).
Also check the air intake manifolds (upper/lower) for any air/vacuum leaks.
These two codes (P0172, P0175) also store Freeze Frames when they log the codes. If your scanner supports reading Freeze Frames you can look at them to see if there's any additional clues.
.
 
1 - 1 of 1 Posts
Top