88 Accord LXi, 245,000 miles. I get a CEL with code 6 (6 short flashes on the LED on the PGM-FI). Replaced coolant sensor to no avail. Shop manual calls for using a system checker harness (honda part number 07999-PD6000A) to test wiring. Is there a way to manufacture this? I'd rather not pay the approx $175 list price for this.