Aftermarket Cat And 'limp' Mode

[Jake27]

Hey, I've had an aftermarket cat in for a while now along with some other parts, but I flash tuned it before the cat was in then had it custom tuned after.

Recently I've become annoyed by the harsh gear changes so I loaded the factory program back up until I can find the time to get to a tuner.

I've had it on the factory tune for about 3 or so weeks and yesterday the engine check light came on... is this the so called 'limp' mode?

[ETM]

Sounds like limp mode to me, if it is an auto the D for drive will also flash on the dash.

The cat is the problem as the 2nd o2 sensor is saying that we have too much flow and the cat must have failed. A flash tune will fix it guarenteed but my mate who owns an exhaust shop says sometimes you can get away with drilling through the o2 senor bung and then welding another one to the top of the old one which tucks the sensor up into the old bung and it does not get hit as hard by the exhaust gas.

[Benny-4000]

Hey, I've had an aftermarket cat in for a while now along with some other parts, but I flash tuned it before the cat was in then had it custom tuned after.

Recently I've become annoyed by the harsh gear changes so I loaded the factory program back up until I can find the time to get to a tuner.

I've had it on the factory tune for about 3 or so weeks and yesterday the engine check light came on... is this the so called 'limp' mode?

this is because the factory tune is checking that you have the factory cat in place. If you run the factory tune with a bigger cat, the ecu will assume that the cat is out of spec and turn on the check engine light. If you take it to ford or any tuner, they can read the dtc from the engine and confirm that the check engine light is on becasue of a cat error.