Date registered: Dec 2005
Vehicle: W211 E320 Bluetec R129 SL500 - $1300 car ........ Ford F350 6l
Location: CA Bay Area
Mentioned: 9 Post(s)
Quoted: 1168 Post(s)
On the top of General section here you will find stickies with codes explanation:
P0158 O2 Sensor Circuit High Voltage (Bank 2 Sensor 2)
P0161 O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 2)
As previous replies indicate -the codes show the results, not the problem itself and need to be interpreted.
Unfortunately interpretation based on 2 codes is having big margin for error. When MAF sensor went bad on our ML320, it triggered 10 codes, while the truck was running still without symptoms.
In this case, not knowing actual mileage I would start with O2 sensor. They are due to replace at 100k miles, so if that is what the truck has, I would replace all of them.
MAF sensors don't wear out like O2 sensors. They just fail occasionally and there is no mileage set when they do, so replacing it would be my second choice.
On other hand after replacing MAF on our E320 (same engine) the mpg went up by almost 15%, so it might be worth buying new MAF and try it. If the old MAF is good, than you will have spare one, what is not a bad thing.
If you don't have scanner to erase the codes after repair, they should clear themselves after some driving. In case of MAF replacement I had to restart the engine 7 times to clear CEL- 10 seconds job.
Last edited by Kajtek1; 05-06-2011 at 09:53 AM.