So, I just got a HFC put in a couple days ago and everything rides nice, but my CEL came on a bit ago. And, before I get flamed, I've done searches and know that with a Test Pipe the CEL is almost certain, but what about with HFC's?

Got it Vagged and here are the codes:
P1237 - Cyl. 1 Fuel Inj. Circ. Open Circ.
P1238 - Cyl. 2 Fuel Inj. Circ. Open Circ.
P1239 - Cyl. 3 Fuel Inj. Circ. Open Circ.
P1240 - Cyl. 4 Fuel Inj. Circ. Open Circ.
P0422 - Main Catalyst Bank 1 Below Threshold

Was wondering if these are all related to the 2nd O2 sensor behind the CAT??

If so, I'll probably take up one of the suggested fixes (Spark Plug Arresters on 2nd O2 Cat, etc.), but I wanted to be sure first.

Also, they flashed the CEL codes and so far so good...no new CEL.

Anyone with experience with these codes and the 2nd O2 sensor know anything helpful?

Thanks.

 

P1237 - Cyl. 1 Fuel Inj. Circ. Open Circ.
P1238 - Cyl. 2 Fuel Inj. Circ. Open Circ.
P1239 - Cyl. 3 Fuel Inj. Circ. Open Circ.
P1240 - Cyl. 4 Fuel Inj. Circ. Open Circ.
all mean there is a short in the wiring to ground check the wiring

P0422 means the cat is bad
Spark Plug Arresters on 2nd O2 Cat is a good idea because it takes the O2 sensor out of the stream which means the O2 sensors don't = voltage which is what throws the CEL

 

Thanks Dave.

So, I definitly think I'm gonna rig up the Spark Plug Arresters, which should take care of P0422. Do you think this DIY will be sufficient? O2 Sensor DIY

As for the other 4 codes, what wiring should I check to test this? Would these be related to the wiring on the O2 sensors or is this something else?

And if you know locations or any other details of the wiring to check, I'd appreciate it. I havent messed too much (or at all) yet with the wiring under the hood...

Thanks
John

 

Make sure you drill the hole in the anti-faulers big enough without hitting the threads..... Been over 15k on my test pipe and no check light from it once...

 

Thanks a4r6.

Do you remember about how long this install took you?

And did you use 1 or 2 Spark Plug Arresters?

 

you only need one arrester and that's the closest to the cat but Ive heard people put both in without any problems, the idea is to pull back the second O2 sensor with the arrester so it doesn't match in voltage to the first one which is what happens when the cat or O2 sensors are going down ( a carboned up O2 sensor could throw the same code ), I assume the HFC (high flow cat) is a good one and not blocked??