So I've had my wife's 2001 Jetta 2.0 up on jack stands for the past couple weeks waiting for parts. I took it to the dealer last month for a CEL that gave code P0420 at AutoZone. I don't have a VAGCOM so that's the best I could do. Before throwing parts at it, I took it to the local dealer and they were able to read a total of four codes, two of which indicated a failing pre-cat O2 sensor. I elected to replace it myself rather than shell out $800 for parts & labor on top of the $58 diagnostic fee.
********************** claimed that the appropriate O2 sensor for a 2001 Jetta 2.0 was a universal four-wire. I ordered it before checking the car (duh), and it turns out the pre-cat sensor is a five-wire. So I searched their website for what looked like the best match, and bought a five-wire Bosch sensor with an OEM plug that matched the Jetta. After an overnight soak of PB Blaster and waiting for a slotted O2-sensor socket to arrive, the crusty old O2 sensor came out with very little effort. I replaced it, then took the original four-wire sensor the website sent me and spliced it to the post-cat O2 connector. All the wire colors matched on both cables. So now I have two new O2 sensors to measure the exhaust cleaning properties of the catalytic converter that the dealer assured me is in working condition. While it was up on the stands, I took a few minutes and changed the oil to Mobil 1 synthetic and replaced the oil filter.
Buttoned everything up and hopped in the car only to be greeted by another dash light. Now instead of just the CEL, the EPC light is on. Perfect. Limped the car to AutoZone (I know, I know), and not only is the P0420 code still there, but now I have two codes related to either the throttle or pedal position sensors: P0226 and P2138. I'm only getting partial throttle from the engine even when the pedal is on the floor. What in the world could I have done to cause these two codes to pop up while replacing the O2 sensors and changing the oil?
Should I check the TPS to see if I damaged any wires? Is it worth taking a look at the pedal sensor too? What about disassembling the sensors and cleaning them? I can't fathom a way that the cat and the TPS would be related.
I recently replaced a coolant flange on my 2003 GTI 1.8T, and it's running well except for an intermittent hesitation in acceleration between 2000 and 3000 rpm. I'm new to VW ownership, and it seems like I've been doing nothing but trying to fix these cars since I bought them in August.
Any help or advice would be much appreciated.