Hi, I have not been on in gite awhile and the DII has been out of service since last OCT. My problem is the check engine light will not go out, I have replaced all four O2 sensors and installed used land rover cats. I spent nearly $1000.00 still no luck. That's why i parked it, I'm going today to have the codes read and try again to get the light to go out so I can sell it at some reasonable price for me and attract a buyer. The DII is in pretty good shape otherwise. Also, the exhaust connection to the muffler where the Y pipe goes into the muffler is cracked at the weld on the muffler and leaking and rattling, could this cause the check engine light to stay on? Whats this DII worth? 2001 SE,148,000 miles.

 

You get the codes read? As for resale value, check KBB or NADA.

 

A crack at the Y-pipe to muffle connection should not cause a trouble code as it is past the downstream O2 sensors and there are no other sensors past that point. Without knowing what trouble code you are getting it will be hard to point you in the right direction. If I had to guess you have a vacuum leak, but I'll wait until you report back with the codes to say for sure.

What trouble codes are you getting exactly? (The exact code #'s are what we need. ie P1171, P0171)

Did you have the codes cleared after you changed out all the parts? Some codes will not clear on there own and you will have to clear them with a code reader.

 

If the light is RED and says check engine - this one is on a timer and only goes out when you pull the timer unit out of the right side kickwall and reset the timer.

The RED check engine light is meant to force you to take the Discovery into a Dealer.

IF this is the AMBER check engine light - then there will be codes you need to correct.

 

This is news to me. I didn't even know there were 2 check engine lights. Thanks for sharing that info

 

The codes are P0161/P0160 and P0141 which I know have to do with. O2 sensors heat and or ops. I found a ts guide on line for o2 Sensors wiring. I'm going to make sure the wiring is good before I replace any o2 sensors again as they are less than two yrs old. Thanks. I will post what I find asap.

 

Look up codes with
http://enginecodemaster.com

For example put in
P0101 for a land rover.

 

Now lets start this conversation with something I have never done on a car enthusiast forum like this. That is say, some people should not post on it. Like the statement above that says the check engine light means nothing.

So here is rule one. The check engine light always means something. The trick is to figure out what it means. Because it is a warning light that is saying hey buddy something is not right with your vehicle. So before you go dumping thousands of dollars into your Discovery you need to get your codes read. In the Discovery and most cars made since 1992 your codes are read by a computer that hooks up to your ODBC II port. Codes come in a variety of numbers that and the quickest way to get them read is to go down to your local big box auto parts store like ORiellys or Advanced and ask them to read your codes, they do this for free.

With that said Big Box Auto Parts Stores readers are cheap generic ODBC readers and only give you a basic code. Like your "engine is to lean on bank 2" has a problem. Now if your purchase a vehicle specific reader that hooks up to the same port, you will get more specific codes, like "engine to lean on bank 2 because the signal from your MAF is poor". These types of codes are better because it pin points your issue.

To get the more specific codes for a Discovery you should get a Discovery specific code reader, like "Autocom/Delphia System" or the "Hawkeye" if you don't want to buy these then go to your land rover specialist and pay him 100 bucks for the better read.

 

With that said

P0160
P0160 O2 sensor circuit no activity detected (bank 2,
sensor 2)
Rear sensor

P0141 O2 sensor heater circuit malfunction (bank 1,
sensor 2)
Rear sensor heater LH bank - short/open circuit (NAS
and EU-3 only)

P0161 O2 sensor heater circuit malfunction (bank 2,
sensor 2)
Rear sensor heater RH bank - short/open circuit (NAS
and EU-3 only)

So I looked these codes up in the RAVE - "Land Rover Work Shop Manual".
What this is telling me is that your two rear 02 sensors are having issues. Your Discovery has 4 02 sensor, two front and two rear.

The sensors used for the rear are not the same as the front so if you didn't change the rear last time or put the wrong ones in you may have an issue. O2 sensors are about 60 bucks each, and are fairly easy to put in. So if you do it, it is free labor, but if you want the work done quickly, cheaply it is a 1 hour job any mechanic can do for about 100 bucks of labor.

Land Rover Parts 02 web page:
Land Rover Discovery 2 Oxygen Sensor (Same Fit As Genuine Part # MHK100930)

Britsh Parts of Utah web Page:
British Parts of Utah-Land Range Rover Sport LR4 LR3 LR2 Discovery Defender Freelander Genuine OEM Accessories Parts

 

If the sensors are all new sounds more like a wiring problem in the harness... check the t clamp at the firewall where all those cables go in... open it up, peel back the covering and look at the condition of the wires, look for crimps, cracked/frayed insulation, bare wires etc. I had several codes when I bought the disco originally, and this was the cause. I moved the wires around, put some electrical tape on the wires where they rubbed through, replaced the fuses, and they all went away and havent come back in 2 years. If not there check the connectors themselves, are they rusted out or full of oil? follow the wires up to the t connector, are they crimped against the exhuast anywhere or frayed through? check where the harness comes in through the firewall, then at the computers make sure they are all tight and secure... not rusted out from water comming in from windshield (common leak spot) or from coolant from leaky heater core. check and clean all the engine compartment grounds, maybe do a continuity check... etc.