My 99 Boxster has been in the garage for 8 months while I worked on various problems. Problems include replacing the water pump, coolant tank, MAF but my toughest problem to solve was p0131, p0137, p0151, p0157. I used the cheap oxygen sensors and they didn't work. I ohm'ed out the heater on each one and they measured between 3 and 6 ohms. Everything I read the reading should be about 2.5 ohms. I also purchased software for my laptop so I can reset the error codes. When the cheap O2 sensors I was reading .15v for sensor1 and .1v for sensor2 after replacing the sensors with O2 from Bosh my voltage jumped to .55v on sensor1 and .51 on sensor2. PROBLEM Fixed
Also beware that your code reading software may be a UK version. My laptop software was indicating very low voltage on Bank1 sensors but in reality it was Bank2 (left side looking at trunk) I proved my theory by disconnecting one of my sensors.
John Maruscak
Linear Mode
