I completed replacement of the Spool Valve Filter (includes the integrated gasket) and the Solenoid Base Gasket. This solved my slow-oil-leak problem.
During the post-repair test drive, after about 4-miles, the CEL came on. About 1-mile after that, the TCS came on. The CEL was a P0131 Bank 1 Sensor 1, O2 Sensor, i.e., the upstream O2 sensor. Additionally, the code reader found a 31-2 PFINH Signal Malfunction... otherwise known as TCS engine retard command (PFINH).
Research here (in OdyClub) states that the P0131 is what actually caused the 31-2 to occur. The 31-2 is meaningless… there’s nothing wrong with the transmission nor the TCS. The TCS does not get disabled when a CEL comes on. Honda designed it so that when a CEL code presents, the TCS light comes on as well to get your attention. Your TCS is still functioning, it just lights with codes that are deemed detrimental to the operation of the vehicle so you get it checked out sooner rather than later.
Prior to the post-repair test drive, I cleaned the oil pan and VTEC areas with brake cleaner (high VOC ingredient). My suspicion is that brake cleaner dripping onto the O2 sensor caused the sensor to send a weird signal, and trigger the P0131.
After driving for a day with the CEL on, I pulled fuse 13 in the passenger side foot well for thirty-seconds. This cleared the codes. Then, I drove about 10-miles. The codes didn’t reappear. Therefore, it appears that the brake cleaner was burned off and the sensor signal returned to normal.
Job completed.
