my s70 is an awd turbo. We are getting engine codes P1238 and P1172.

1. Check the freeze frame data when the fault set, and also the fuel trim numbers, to determine if the system was lean or rich. 2. Scan the Mass Airflow (MAF) sensor output. It should be 4.5 g/s at idle in Neutral, and 160 g/s or more at maximum output (5,000 RPM at full throttle) just before the transmission shifts. 3. Check the fuel pressure. It should be 55 to 60 PSI. 4. Check for signs of an engine vacuum leak. Trouble code P1171 can set because the fuel system is too lean or rich, so the fuel trim numbers should be checked to determine if fuel is being added or subtracted. A minus (-) sign in front of the fuel trim value indicates that the Powertrain Control Module (PCM) is subtracting fuel. Pattern failures have been seen, due to the MAF sensor causing the code (P1171) to set at cruise speed. As a general rule, fuel trim numbers close to 10 are OK, but if the numbers increase to 15-19 (either + or -), the PCM will set an intermittent fuel trim code. If the fuel trim values increase to 20, it sets a hard code.