P0432: 2/1 CATALYTIC CONVERTER EFFICIENCY
Monitored & Set Conditions
Catalytic converter efficiency is monitored after engine warms up to 147°F (63.9°C), throttle has been open for 180 seconds, vehicle speed is more than 20 MPH with engine speed at 1200-1700 RPM and Manifold Absolute Pressure (MAP) sensor vacuum is 15-21 in. Hg. DTC will set when catalytic converter efficiency deteriorates and switching rate of downstream oxygen (O2) sensor approaches the switching rate of the upstream O2 sensor. If at any point during the test, the switch ratio reaches a predetermined value, a counter increments by one.
Possible Causes
Intermittent Condition
Visually Inspect Catalytic Converter
Exhaust Leak
Engine Mechanical Problem
Upstream O2 Sensor Older Than Downstream O2 Sensor on bank 2
Catalytic Converter
found this good tip to share
try fuel enrichment with propane, and watch o 2 s. also create a vacuum leak and watch o 2 functions.sometimes these o 2 s look fine but will all of the sudden fail and stop reading or have an intermittent short and signal will go 1.25 volts and stay there. if o2;s consistantly work cold or hot then throttle stick the gas pedal at 2000 -2500 rpm and get the cats nice and toasty and do a temp reading front and rear of cat. a working cat should have a 100 degree increase in temp out the rear of cat. this is telling you that a catalytic reaction is happening in the cat. it actually makes the exhaust hotter out the rear of cat if its working. if the temp is the same or colder out the back then chances are the cat is worn. also doing the throttle stick at 2500 rpm have a voltmeter hooked to both upstream and downstream o 2 s and watch the signals. the front o 2 should fluctaute btwn .1 v- .9 v like a wave. the rear o 2 should remain stoich anywhere btw .2 v- .7v. a good cat will cause that rear o 2 to be pretty much flatline in that voltage range.if that rear o 2 changes with the front o 2 like a mirror effect than chances are you have a bad cat. with these cat codes i always check for vacuum leaks and always make sure the o2 s have good reaction to fuel enrichment and lean reaction before i bite the bullet and sell a cat
May 9, 2010 at 7:00 PM
