2008 D40 auto problem

Hi All

I have the following problem with my auto. I have taken it to Nissan and an auto mechanic and the proposed solutions are - "might be the transmission computer" and "might be easier to replace the transmission", respectively.

When taking off from stationary at 33% to 50% throttle, it will get to about 2nd (or 3rd) and then suddenly kick back to 1st with a bang. The engine will then rev out and won't up shift for several seconds. I usually need to let the throttle right off for a couple of seconds and then the trans sorts itself out.

When this event occurs the the overdrive off light illuminates.

It is an intermittent issue. However, it seems to occur more with increased load. Eg. Taking off from lights up a hill.

Any ideas would be greatly appreciated...

Does it do it if you manually shift through the gears? My mums Merc used to do a similar thing after i took it out and gave it a hard time one night (burnouts etc) and after a week or so of shifting manualy it was as good as new. Luckily.

Welcome to the forum.

Sounds like something in the transmission is screwed - it is not supposed to do that at all. Mine is a 2009 which is near enough the same thing and mine is smooth as silk even after 102,000km.

While it could be the TCM which lives in the sump of the transmission, I'd actually take a stab at cleaning the electrical connectors on the gearbox first, in case it's an intermittent signal to the gearbox for something like throttle position, or engine load% - both of which impact on gear selection.

I'd then clean the valves in the gearbox. Something caught in them could easily cause the gearbox to behave strangely, if it gets caught intermittently then your symptoms are easily explained.

A replacement box will cost you more than a decent set of tits in Thailand. I'd be tempted to take it to an auto transmission specialist and see what they say. Nissan follow the recipe book for troubleshooting and diagnosis - all too often they'll replace fuel pumps, injectors and fuel filters just because a seal isn't sitting properly in the fuel filter, because the book tells them to.

Thanks Old.Tony.

I have got a lead on another auto specialist, so I might give them a go at it.

I didn't think of throttle or load sensor. If it is a sensor issue, then TPS or load would seem more likely than speed ( the first "speciallist" theory). It would be good to put a data logger on it to see if a sensor drops out during the event.

When then issue isn't occurring the trans is perfect. Intermittent problems are very frustrating...

Ahhh. I had the car in 4Lo first gear on the weekend and it continued happening. It obviously isnt kicking back a gear, but going into limp mode. That prompted me to search for limp mode issues and there appears to be lots... I am please to now have some things to try...

Have you tried doing a self diagnostic test for the transmission to see if it brings up any fault codes?

Have you got a smart phone or laptop you could use diagnostic software on? You cab get either Bluetooth or USB obd2 scanners off eBay fairly cheap and there is quite a lot of diagnostic software you can use. I'd be checking throttle position and engine load values to see if they spike randomly when it does it..

bods said:

Have you got a smart phone or laptop you could use diagnostic software on? You cab get either Bluetooth or USB obd2 scanners off eBay fairly cheap and there is quite a lot of diagnostic software you can use. I'd be checking throttle position and engine load values to see if they spike randomly when it does it..

Click to expand...

If it's a fault in the TCM it may not show on the main ECU's fault codes.
The transmission has its own computer (TCM) and diagnostic procedure for revealing fault codes. There is 17 different fault codes relating to the transmission only.

I have now realised there are two separate issues, althought they are likely to be related. If in Drive, it will kick back a gear and not shift up - but doesn't appear to go into limp mode, seems to be a transmission issue. However, if in Lo 1st, and under load it goes into limp mode.

i going to take it back to Nissan for the 3rd time and see what they come back with.

JPMC - How do you run a self diagnostic test on the transmission?

Perhaps I should try that before potentially wasting time and money...

Here goes the procedure.

1. Start the engine with selector lever in “P” position. Warm engine to normal operating temperature.
2. Turn ignition switch ON and OFF at least twice, then leave it in the OFF position.
3. Wait 10 seconds.
4. Turn ignition switch ON for at least 2 seconds. (Do not start engine.)

Once that's done then follow on with this:

1. Turn ignition switch OFF.
2. Keep pressing shift lock release button.
3. Move selector lever from “P” to “D” position.
4. Release accelerator pedal. (Set the closed throttle position signal ON.)
5. Depress brake pedal. (Stop lamp switch signal ON.)
6. Turn ignition switch ON.
7. Wait 3 seconds.
8. Move selector lever from “D” to “3” position.
9. Release brake pedal. (Stop lamp switch signal OFF.)
10. Move selector lever from “3” to “2” position.
11. Depress brake pedal. (Stop lamp switch signal ON.)
12. Release brake pedal. (Stop lamp switch signal OFF.)
13. Depress accelerator pedal fully and release it.

The O.D. OFF lamp should start flashing now.
You will get a series of 17 flashes.
During the flashing if one or more times the light stays on longer than the others that is the fault number. (ie four short flashes then one long one and then another 12 short flashes gives the fault code 5 which is: Input clutch solenoid valve.

The fault codes are as follows:

1. Revolution sensor
2. Direct clutch solenoid valve
3. Torque converter clutch solenoid valve
4. Line pressure solenoid valve
5. Input clutch solenoid valve
6. Front brake solenoid valve
7. Low coast brake solenoid valve
8. High and low reverse clutch solenoid valve
9. PNP switch
10. A/T fluid temperature sensor
11. Turbine revolution sensor
12. A/T interlock
13. A/T 1st engine braking
14. Start signal
15. Accelerator pedal position sensor
16. Engine speed signal
17. CAN communication line

See how you go and if you find a code let me know and I'll see what info I can give you on it.

JPMC

Thanks!

I did the trans self diagnostic. The OD light was flashing in a series of off for about 3 seconds, then 1 long flash followed by 22 sort flashes. Then repeat.

Any thoughts..?

How many flashes before the long one?
And are you sure there was 22 after the long one as there should have only been 16 before the long one came back again.

There is 17 flashes in total to relate to a fault code.
If you start the diagnostic and get 5 short flashes then a long one followed by 16 short flashes then another long one then that is code 6. (Front brake solenoid valve).

The first flash was definitely the long one and 22 short flashes to follow. I ran the process twice to be sure.

Well I'm sorry but I don't know about the 22 flashes as my manual says there should only be 17 excluding the first long one.

If the flashes after the first one are all the same then it's not picking up any faults.

This is just getting weirder and weirder.

If it's flashing something outside the proper response range then it's either got a bad electrical connection which is confusing issues, or the TCM is stuffed.

Might be time to check all of the electrical connections on the outside. Remove each plug, clean it well. Check the inner parts of each plug to make sure there's nothing loose inside, then reinstall it and move to the next plug.

Replacing the TCM won't be cheap. Replacing the box will be worse.

Hi JPMC
I also tried the diagnosis above... and I kept getting 1long, 17short flashes...
according to the code numbers/ values you mentioned, and you did explain...
5short 1long 16 short (not counting the first 5) should b total of 17 flashes..right?
How do you work out my readings/flashes? After reading the flashes for a couple of minutes the sequence was the same.. 1LONG 17SHORT. Is that reading any faults do you think?
my issue is the change of gear (A/T) BEETWEEN 3rd to 4th on normal driving conditions,70kph. specially when you are trying to overtake another vehicle and by pressing the accelerator you expect it to drop a gear for that extra bit of grunt. As i explaind to OldTony a couple of weeks ago, and he suggested dirty or leaking vacuum hoses, which I have replaced all of.... I have put in a EGR blaking plate 4 mths ago, oil catchcan but still got oil coming throught pipe into intercooler... could it be the Turbo thats causing this?
any suggestions. ...?
thanks in advance...

Ok going off this I would say it would relate to error code #1 which is Revolution sensor (Vehicle speed sensor in the auto).

Sorry to say but if it is this sensor then it involves removing the sump off the transmission to get to it and the easiest way of diagnosing is to go for a drive with a Nissan dealers Consult-II plugged in.
Although it may not be nice for the pocket doing this, it could save you in the long run if the consult picks up that the cause is a wire related problem rather than the sensor it's self.

To do the same diagnostic with out the consult means dropping the oil, then removing the TCM to get to the wires and then testing. If they are fine then replacing the sensor.

Using the consult once diagnosed if it's the sensor and not the wires then it's a matter of dropping the oil,remove the sump, replacing the sensor, refit the sump and refill oil.