2003 Disco 2 158K miles. orig owner. replaced coil pack all wires, plugs at 130k miles.

After my cats were stolen for 2nd time I added a steel shield underneath. the front bank oxygen sensors are blowing heater element codes not detected. PO155, PO154, PO135. Truck ran fine for 5K miles and now I have random misfires PO300, 304, 302, 308, and the ABS light comes and goes and now I have brake squeal (Landrover pads and rotors just 5K miles back. Code PO1590. ABS sensors.. all sensors have power from the ECU. CAN ALL THESE ISSUES BE FROM A VACUUM LEAK? i tried spraying entire engine with WD40 and noticed no change. also have a refrigerant leak and compressor clutch not engaging.

tnx

 

Did they unplug the O2 sensors or cut the lines? Brakes and squeal and ABS light I am guessing your pads are worn to the wear bar sensor triggering the ABS light or the sensor got out of position or cut or something - check your pads. Regarding your O2 sensors the wire harness has one main line that routes off the main harness and goes down below the driver side which connections for you pre cat driver side , post cat driver side and then goes up and over the transfer case and connects to the pass side post cat. So there is theee of your four. I would double check the line coming down from around the firewall and make sure it is not cut somewhere. Guys are jacking your cats, u likely they will take the time to disconnect the connections.

 

thank you for ur reply. The cut the entire pipe .replaced all and used top Walker sensors. They were good for a week and then off line. What vacuum leak (hose) could cause this issue. Also, oxygen . Sensors off line cause engine misfires?

 

non functioning O2s will not cause misfires.

 

Jeff- all your codes are related to the O2 sensors before the cats. I think they might have screwed up your wiring when they chopped out the cats.
P0154 O2 Sensor Circuit No Activity Detected (Bank 2 Sensor 1)
P0155 O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1)
P0135 O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1)
This one is after the passenger side cat
P0159 O2 Sensor Circuit Slow Response (Bank 2 Sensor 2)

This is totally a guess on my part, but is it possible that the heat being transferred to the steel plate from the cats is messing up something?

 

P01590 is a general ABS fault code. You need to get hold of a reader that can access the ABS system to read the specific codes that underlie that one.
That system shouldn't have anything to do with your cats or O2 sensors.

 

Thank you Matt,
maybe the shield is the problem but do not wish to go to jail for manslaughter if someone tries to jack my cats a 3rd time.
i will see if the manifold gasket bolts need adjustment. Might need to remove shield to pass inspection. I will try a smoke test on vacuum hoses first
and then diagnose the misfires. Maybe plugs are fouled from ox sensor sending too much fuel.
really sucks cause trout season is April 1st

 

I would try starter fluid for the leak. Works better than wd40. I had a leak that showed up on a smoke test but not spraying junctions.

 

Trout season is critical.

 

Hi all,

i bought a smoke machine for $85 bucks on Amazon. Powerstroke M1. Has a compressor and runs on baby oil. Removed MAS and with cone attachment included machine produced tons of smoke and found 2 vacuum leaks both small hoses connecting to throttle body. Repaired and misfires are gone. I now have just 2 oxogen sensor codes PO155 and PO154. I noticed that the y pipe to manifold is leaking so those uts need to be heated and tightened and hopefully that will help.

The right side brake pad was in bad shape from freezing caliper. Left side in good condition. Replaced both pads with EBS green and bled brakes. all brake codes gone but have not driven rover yet.

Thanks everyone. Will update oxogen sensors later.