I've been experiencing a recurring P0734 Gear 4 Incorrect Ratio fault on my rover. It seams to occur about every couple of weeks. The light comes on at various times at low speeds and I have not been able to pin it to a shifting sequence or any driving conditions. Posts do not exist for a Rangie but there are several for a Disco. Any ideas?

 

How many miles on the truck, how old is the tranny fluid and how often is it changed? Does the light go off by itself?
Mike

 

104k miles on the truck. Tranny fluid was changed at 90k. The dealership may not have changed the filter and I am trying to find that out.

It looks like other posts recommend replacing the MAF and O2 sensors. The light does seem to come on under acceleration so fuel mixture is a definite possibility. I altered my daily route recently so I can't really tell if MPG has changed.

I am thinking about replacing the PCV, MAF, O2 sensors, and plugs/wires. Plugs/wires are due anyway but if its something with the mixture and ignition those things should solve it.

I have an OBD II scanner so I just reset the code myself. In the manuals they tell you to ignore the code - that's humorous and frustrating one in the same.

Thanks for the help.
-Chris

 

Your are not having a MAF problem, to be a problem you would also need codes showing both banks running lean.
As for you suggestion on changing out the plugs and wires, this is a good idea based on the mileage of your vehicle, will it correct the problem is hard to say but it will be a step towards overall better performance. Pretty much the same thing holds true for the O2 sensors, they are getting tired at you mileage and it will be another step in the right direction.
Try and order a set of Magnacor wires and shop around for the o2's, should find them in the mid $65 range.
Mike

 

Thanks for saving me the $250 on the MAF. Ordered the wires you mentioned from Rover Connection today and the rest from Atlantic British. I don't know if it's ever a good thing when you "qualify" for free shipping by spending so much. 4x$65 for the sensors will certainly put a hurtin on the beer money. I'll post back in about 3 weeks and let everyone know if the light is staying off.

-Chris

 

Ugh. I did the following:
[ul][*]new plugs & wires (Magnacor)[*]new tranny fluid[*]replaced all 4 sensors[*]PCV hoses[/ul]
Still ending up with the same result - the light comes on in 1 - 2 weeks under low-speed accelleration. Any other ideas?

 

I broke down and called a dealership for some assistance. They said it was the MAF. I got one online for under $200 so we'll give that a whirl. If I don't post here agian within 2 weeks then it solved the problem.

Thanks,
-chris

 

My son has a 2001 Land Rover Dicovery 11 which starts normally but after 10 minutes it will shut off and not start for a long time. What do you think could be the problem?

 

karenstarr -

This is very common symptom for the $75 crank shaft position sensor. The litmus test is when it happens, check for spark with a spare plug attached to a plug wire and laid on the mainfold. Don't hold the plug! When the CKP sensor dies, the spark is lost, and the sensor (in the warm engine block) has to cool off. You can also pour cold water on the sensor to speed this up. Here are some pages on the sensor, if DIY, plug it in, let it hang down, and be sure every nut and spacer goes back on in exact sequence. Spacing is critical. Sensor is rear area of engine, driver side (in North America).

 

For sure it is the MAF. i had the same problem. i wish i saw this sooner for you to save on all that other stuff you bought.

mine got so bad that the gears would slip real bad between gears.