I know its here somewhere, but I am unable to find it ... Which side of the engine is Bank 1? Bank 2? I am getting intermittent Slow Down light and error code P0428 - "Catalyst Temperature Sensor High Input (Bank 1 Sensor 1). When it occurred, I checked temperature of both cats and the external temp was right at 500 deg F. The error seems to occur within a few minutes after starting and only driving about 5 or 6 miles when Slow Down light appears. At that point the oil temp is not even up yet. The times this occurred, I pulled over, shut off the engine and let it rest. Restarting has given me another Slow Down light, then it goes away and stays away. Today, I checked the resistance of both catalytic thermo-couples and they were both at 3.0 ohms. Except for the Slow Down light, which shuts fuel supply to the cylinder bank, everything else runs fine. Using process of elimination and knowing that the thermo-couple ECU is prone to failure, I am ordering a new control unit for the therm-couple. But, I just need to know which side is Bank 1 ... so I replace the correct one. Thanks, Steve
As is usually the case when trying to sort out an intermittent problem ... after unplugging the thermocouples and the cable to the ECU on both those catalyst temp control devices ... now there has not been any more SLOW DOWN lights. Just for ****s and giggles I swapped the left and right control stations Side note, many people call these devices catalyst ECUs ... which I wonder about. I do not believe there is anything computer related with these things. It appears that they are only an amplifier to step up the voltage from the thermocouples so the ECU will know what to do them. The thermocouple only puts out a few milli-volts ... and the ECU needs a linear voltage in the 1 to 5 volts ranges Any hoo ... swapping left for right did not reveal anything either. When the new catalyst temp control stations arrives, I will replace the one that was part of the trouble code that I saw and hope for the best. Maybe Dino is right ... the one on right was just going bad and needed to be more left leaning. Steve
Steve, I had the same problem. I replaced the bank 1 cat ECU with the most current ECU part 179278 (green top) and it solved the problem. The old part showed signs of cracking between the case and the material sealing the components.
Both of mine were the newer P/N (green top). But, I went ahead and replaced the one that was showing up in the DTC code. But as I stated earlier, after unplugging and swapping left for right ... I have not had any problems. I replaced the one that may be bad today and drove about 45 miles ... no problem today. I haven't replaced the engine bay panels yet. I will do that tomorrow ... I expect after I go through the trouble of replacing the panels that is sure to make the SLOW DOWN light come on again. Steve
