That darned orange engine light

A few weeks ago we took our TF through blackpool's illuminations and while the trip itself was fine, the orange engine light would flash when doing above 60 on the motorway, then go out. It did this a couple of times on the way there and on the way back, but there was no loss of power and everything was ok.

However last week it started doing it again but this time at lower speeds, and while heading home the light came on and stayed on so I went to our friendly mechanic (who services the main family car) to have the fault codes read.

There were 2 codes, P0300, which is a random misfire, and also P1590, which neither of us had ever seen before. Looking on the LandRover forums brought this code up as an error reported by the rough road sensor, but the MG TF does not have one of these. Looking further brought up an interesting thread on another forum about the MG ZR, where this fault code is generated by the ABS ECU... My car does not have ABS...

Further searching showed that the MG ZR's without ABS still had a sensor on one of the front wheels, which gave speed readings to the ECU, and if this sensor failed or got dirty, that too would generate a P1590 error code. So I looked in the TF's wheel arches to see if the was any wiring to such a sensor, there was none.

Both mine and our mechanics feeling is this is a speed sensing issue, though the speedo in the car is not showing any issue and is fairly accurate when compared with the readings I get from my sat nav. So my question is, has anyone else come across this fault code on their MG and if so, did you find the solution? It looks like I'll be looking at the speed sensor and it's wiring, though it would help if I had a wiring diagram. I assume those are part of the servicing manual though.

I'm off to work shortly Mal. Maybe someone can access the electrical manuals on the new site and email it to you. I'm not sure it contains what you're looking for. Worth a look though.

Leigh

EDIT:- I downloaded most of them now. I can send some of them to you via email if you like? Others are quite large (50mb +). I could send those via msn messenger if you have it. Gimme a shout when I'm around if you want them.

Awesome facility. Thanks Psymon.

Mal,
I know our mk2 F has an ABS type speed sensor on the rear nearside wheel. I always assumed this was because the hub had been replaced at some time and the ABS hub was the only one available, but now you mention this it would be worth checking your nsr wheel hub.:shrug:

David Aiketgate wrote: Mal,
I know our mk2 F has an ABS type speed sensor on the rear nearside wheel. I always assumed this was because the hub had been replaced at some time and the ABS hub was the only one available, but now you mention this it would be worth checking your nsr wheel hub.:shrug:

Interesting, I've not seen anything on the TF rear wheels, though it was raining when I had a look so I'll have another look over the weekend while the sun is out, though I've been looking through the service manual for the TF, however it seems the MEMS 3 cars do not have the sensor on the wheel, though I'm pretty sure the MEMS 2 cars do.

There is a feed for the tachometer from the MEMS ECU, which is averaged across all cylinders in case of variable spark timing so if the car is misfiring (which it is once warm), the odd reading to the MEMS ECU may be triggering the P1590 error. While it mentions where the signal comes from for the speedo, I'll have to look through the engine management section to find where the tachometer info comes from.

Leigh Ping wrote: I'm off to work shortly Mal. Maybe someone can access the electrical manuals on the new site and email it to you. I'm not sure it contains what you're looking for. Worth a look though.

Leigh

EDIT:- I downloaded most of them now. I can send some of them to you via email if you like? Others are quite large (50mb +). I could send those via msn messenger if you have it. Gimme a shout when I'm around if you want them.

Awesome facility. Thanks Psymon.

Thank you Leigh and thank you Psymon for this.

I think one of my website addresses will be able to handle it, though I should be on msn some time soonish. I accessed the TF manual here, thanks for pointing me in the right direction (mostly access the forums though tapatalk so have no idea what's on the main site, should go via browser more often).

If you try [email protected] that email address should be able to handle large attachments. I spend most of my time browsing with the iPad these days so having them in email makes them accessible whatever device I'm on.

Much as I like them, the file restrictions on iPad and iPhone make them irritating sometimes.

Well I fixed it, decided to try and replace the spark plugs today and got right into the engine bay, all covers off only to discover my plug extractor would not fit into the hole where the spark plug lives.... Darn!

So I decided to do some looking around while the engine access cover was off and realized the ht leads were not really laid out properly. So I took the coil packs off and re-seated them along with the ht leads. I also took the opportunity to replace the air filter as this is a pain to do at the best of times.

Lo and behold, the car started first time without having to push the accelerator at all, something that has never been the case up to now. Also the idling was that bit smoother, and after a quick test run the whole car just felt that bit better. Next time it was started, the engine light went out and has not come back on since, not even when pushing the car on the nice long country road we have nearby.

Looks like it was just dodgy connections this time

Good to hear you've solved the problem! :yesnod:
I've had that problem on other cars, where the plug leads are sparking across each other and you get multiple misfires.
Quite spectacular to look at when it's dark too. :bust:

Thank you David, though in this case it was the leads not being seated correctly, so there was strain on the connections to the coils, better routing of the cables and re-seating everything made it run a lot smoother, especially once warm, which was when the slight misfiring would start to happen.

It'll be going on a nice long run on Wednesday night, but so far it all looks promising.

:thumbsup: :broon: