My 98 D1 (AEL) threw a P0138 code, corresponding to driver's side downstream O2 sensor. Curious about what's happening, I checked the live data on my TurboGauge (a knockoff ScanGauge) and saw some fuel trim numbers that looked out of range. I forget the exact values, it was a few days ago.
The scanner gives separate readings for each of the four oxygen sensors. My problem is that I can't figure out which data point on the scanner refers to which oxygen sensor. The scanner gives me 8 different readouts that I can cycle through: SF1, SF2, SF3, SF4 (short term fuel trims) and LF1, LF2, LF3, LF4 (long term fuel trims). The readings on data points 1 and 2 are low single digits, the readings on data points 3 and 4 are higher. Since I'm already getting an OBD code I'm inferring that the downstream driver's side (P0138) corresponds with either SF3/LF3 or SF4/LF4. Beyond that I can't pinpoint which is which.
The user's manual doesn't give any information about which data point goes with which sensor. I'd appreciate any insight that helps me identify what goes with what. Perhaps the ScanGauge manual has this info and the data points are the same across tools.
The scanner gives separate readings for each of the four oxygen sensors. My problem is that I can't figure out which data point on the scanner refers to which oxygen sensor. The scanner gives me 8 different readouts that I can cycle through: SF1, SF2, SF3, SF4 (short term fuel trims) and LF1, LF2, LF3, LF4 (long term fuel trims). The readings on data points 1 and 2 are low single digits, the readings on data points 3 and 4 are higher. Since I'm already getting an OBD code I'm inferring that the downstream driver's side (P0138) corresponds with either SF3/LF3 or SF4/LF4. Beyond that I can't pinpoint which is which.
The user's manual doesn't give any information about which data point goes with which sensor. I'd appreciate any insight that helps me identify what goes with what. Perhaps the ScanGauge manual has this info and the data points are the same across tools.