Think you know Rover electronics? Prove it...please.

[DiscoIIBrandon]

First off, thanks if you are reading this and hoping to help. I'm hoping to save $150/hr that I will end up paying just to have my problem diagnosed...led alone fixed, if you can't help me.

Somewhat quick summary, problem listed next.
'99 D2 bought 2 years ago, 105k miles.
All major service has been done since purchase, all new fluids, new head gaskets to boot.
New MAF, reman ALT, copper plugs, pricey wires, etc, etc.

Problem: codes P0134 & P0154 (front O2's NO ACTIVITY) and so the truck is running in OPEN LOOP constantly, burning more gas than usual, and seemingly eating my cats rather quickly.
What I've done to date:
-replaced the O2 sensors thrice with Atlantic British O2's and then BP of Utah front O2's. I would say it isn't the sensors at this point.
-w/ multimeter, checked that the O2 plugs (connectors) were receiving power, they are.
-w/ multimeter, checked that the other three wires in the connector had clear flow of info TO the ECM, checked out. (doing pin-outs is fun...or not)

It seems that the sensors are good, they are getting power, and the wiring between the sensors and the ECM is good.

So, where does that leave me? Is my ECM bad? Can an electrical guru with the right equipment fix/repair the ECM and the communication with the sensors? Or will this just inevitably lead me to buying a new/used ECM and getting it flashed to my truck? How do I even know that it must be my ECM now?

Thanks in advance, DIIB.

 

[p m]

What I would do first is to take an OBD-2 scanner and see if the O2 sensors' outputs make any sense - it would tell you what ECU thinks the sensors say.

 

[DiscoIIBrandon]

What I would do first is to take an OBD-2 scanner and see if the O2 sensors' outputs make any sense - it would tell you what ECU thinks the sensors say.

Did that. Watched with live data after installing the 2nd and 3rd sets of new sensors. The value didn't move...at all. Stayed right at the default value (forgot what it is, maybe .45 or something). That is what led me to check that the sensors were getting power and that the connection between the connector and ECM were good.

I suppose the wires between the O2 sensor connectors and ECM could be bad, but I DID do the pin-outs with each to confirm they were good with a multi-meter.

 

[lutz]

What brand of o2 sensor's are you using ? I had the same problem with my 99 d2 i had to put Bosch orange plug o2's in.All other o2 would not work correctly.

 

[DiscoIIBrandon]

What brand of o2 sensor's are you using ? I had the same problem with my 99 d2 i had to put Bosch orange plug o2's in.All other o2 would not work correctly.

Atlantic British for the first couple sets (good customer service sent out two sets), and then British Parts of Utah O2's with the orange connector.

Also, I swapped in known-good-working O2's from another D2...same story.

 

[NikeCheck246]

Just a shot in the dark...I wonder what market your ecm is set to? If I am not mistaken, there are markets where cats/o2s are not required, and therefore the ecm is not programmed to read those components. I could be completely off, but I know this to be true for Discovery I's, so why not II's?

 

[DiscoIIBrandon]

Just a shot in the dark...I wonder what market your ecm is set to? If I am not mistaken, there are markets where cats/o2s are not required, and therefore the ecm is not programmed to read those components. I could be completely off, but I know this to be true for Discovery I's, so why not II's?

I don't know, but I'm pretty sure mine is set to a market that needs input from the O2's..hence the codes and running dang rich.

I would love to have an ECU set to that market though, I'd happily remove the O2's and cats.

 

[Hugh166]

When you say you pinned out the wires from the O2 sensors, what did you do check for continuity? Also I'm assuming that since you have been at the connectors for the O2 sensors so many times you would have spotted oil contamination on the connectors.

 

[DiscoIIBrandon]

When you say you pinned out the wires from the O2 sensors, what did you do check for continuity? Also I'm assuming that since you have been at the connectors for the O2 sensors so many times you would have spotted oil contamination on the connectors.

Yes, checked for continuity and all 3 wires checked out (the 4th is power which is good too).

And yes, not only did I clean the connectors each time, I also zip-tied them up and out of the way of oil AND wrapped them up in electrical tape after the 3rd time.

This was all done months ago, and now I am re-visiting the problem and determined to get it fixed. The gas mileage is worse than normal, and I'm probably going to need new cats again. I need a beer just thinking about this problem again.

 

[Mrmerlin]

have you swapped in a new Rover MAF?
do you have any vacuum leaks?

 

[DiscoIIBrandon]

have you swapped in a new Rover MAF?
do you have any vacuum leaks?

Yes, new Rover MAF. Not sure about vacuum leaks, how do I go about checking for those? (sorry I'm a rookie at best)

 

[Hugh166]

Just to make sure you have covered everything before condemning the ecu which is where it sounds like it is going try doing a voltage drop on the wires instead of just testing for continuity, if you need help with doing that shoot me a pm and I will give you a walk through

 

[dgi 07]

Hey, I remember this issue from LRF. I though we concluded it was the ECU?

 

[XCELLER8]

in the "got nothin' to lose" dept....disconnect the battery, remove the ecu, open it up if you can and just see if its wet inside.....or the connections are corroded, it's happened to many of us.

 

[ptschram]

When you were probing the leads, did you monitor the output of the oxygen sensors with an oscilloscope or graphing meter?

 

[DiscoIIBrandon]

When you were probing the leads, did you monitor the output of the oxygen sensors with an oscilloscope or graphing meter?

No, I've never used either of items mentioned and will need help to do so, but can get local help.

Anything in particular I should look for or need to know when doing this?

Thanks again to all.

 

[DiscoIIBrandon]

Hey, I remember this issue from LRF. I though we concluded it was the ECU?

Well, yes, many stopped with "must be the ECU". However, everyone with any reputable experience tells me, and I quote, "I've never seen (or heard of) a Land Rover ECU going bad", and totally dismiss the ECU.

And since the only local source capable with these electronics is $150/hr and isn't Land Rover experienced, I thought I would go through everything again and make sure I didn't miss anything, which entirely possible since I'm completely inexperienced.

 

[DiscoIIBrandon]

in the "got nothin' to lose" dept....disconnect the battery, remove the ecu, open it up if you can and just see if its wet inside.....or the connections are corroded, it's happened to many of us.

Will do this to.

 

[DarylJ]

Just a shot in the dark...I wonder what market your ecm is set to? If I am not mistaken, there are markets where cats/o2s are not required, and therefore the ecm is not programmed to read those components. I could be completely off, but I know this to be true for Discovery I's, so why not II's?

Upstream O2s are not emissions components. Regardless of the market the vehicle is sold in, the upstream O2s are what the ECU uses to set fuel mapping.

I think he needs to scope the O2s at the ECU and see if he is getting an appropriate voltage/signal as a next step. I'm guessing the answer is going to be "no", but if he is and live OBDII data shows no activity the problem is either the ECU connector (trivial to continuity check) or a problem with the ECU, likely cold solder joints or tin whiskers.

 

[dgi 07]

Well, yes, many stopped with "must be the ECU". However, everyone with any reputable experience tells me, and I quote, "I've never seen (or heard of) a Land Rover ECU going bad", and totally dismiss the ECU.
.

Which i get and understand, but stranger shit has happened. I distinctly remember walking through the entire diag process with you. oh well. Good luck!