P0420 Cut off cats?
 

My truck keeps giving me p0420. been told to replace the pass side cat. Can i just cut it out? i dont wanna pay 300 for something that i dont really need. My truck runs fine. no emissions laws in ky. any input is appreciated.

No, I tried one cutting down the side but in a long run there is a bad effect. better replace it.

Since you failed to provide engine size, I can't give you specific info. ALWAYS give this info if you want help for a specific problem.

The Simple Answer: ~ Replace your converter.

Here's how it works, in case anyone's interested.

DTCs

P0420 Catalyst Efficiency below Threshold Bank 1

P0430 Catalyst Efficiency below Threshold Bank 2

Monitor Execution

Once per Driving Cycle. (On MIL equipped vehicles this test must be failed three times before the MIL light is switched on.)

Monitor Sequence

The following tests must be complete before the Catalyst Monitor can run:

♠ HO2S monitor tests complete and no DTCs
♠ No Fuel Trim DTCs
♠ EGR Monitor Complete
♠ No Misfire DTCs
♠ No SAIR (Secondary Air Pump) stuck on DTCs (where fitted.)

It should be noted that faulty HO2S sensors do not produce the DTCs P0420 and P0430. The sensors must all be tested and shown to be reliable before the Catalyst Monitor can be called by the Executive.

Sensors OK

The following sensors have been tested and shown to be good before this monitor can be run:

♠ HO2S - Heated Oxygen Sensors
♠ ECT - Engine Coolant Sensor (Sub-in CHT where applicable)
♠ IAT - Inlet Air Temperature
♠ MAF - Mass Air Flow Sensor
♠ TPS - Throttle Position Sensor
♠ VSS - Vehicle Speed Sensor
♠ CKP - CranKshaft Position sensor.

DRIVEABILITY CONCERNS

None. With no MIL light if a catalyst has failed the owner will be unaware of it until the MOT emissions test. On the 24V, one good catalyst and one failing one may be borderline on emissions. Depending on the efficiency of the Fuel Trims, the spark plugs and the INJectors it may be possible for the 24V to squeak through the emissions test with two failing catalysts, although performance of the engine will be poor - running smoothly but well down on power. On the 16V DOHC engines with one catalyst this is less likely.

CATALYST RATTLE

Symptoms were a rattling from the affected catalyst. If the catalyst brick had moved, this could cause a restriction in exhaust gas flow. Symptoms for that, in addition to the rattling, was a marked loss in engine power and perhaps a whistling noise. EGR pipes could also be dislodged by the increase in exhaust pressure.

Replacement catalysts have proved to be more durable, but their service life may be perhaps six years.

Yeah sorry....its a 2005 5.4. I guess Ill need a new one then.

Oh I need to add. I have a K&N CAI on this for about 6 months. Code has been coming on for a month. I told bill at PHP about the CAI, so i figured the gryphon would correct that anyway. Could this cause the code? I have heard about it causing a lean condition, but isnt that a different code? Its also got a SI/DO Flowmaster 40 muffler.

Cut all 4 cats out and replace with 2 hi-flow cats. The part numbers are 94106 and you can pick them up for $96 for the pair at performancepeddler.com with the "clubgp" code.

It sounds like the CAI tipped the A/F over the edge and has ruined a cat.

I'm not sure he has 4 cats on the 05?

https://www.f150online.com/forums/me...943-216642.gif

It's really 50/50 with the 05's. If he has the 2 cat system, then it will be straight forward. Cut the 2 cats off, replace with hi-flows, remount O2's after new cats.

It depends on the build date

you just beat me :lol:

:beers: