CVT Issue - No or very little drive - P0744

305 Views 7 Replies 5 Participants Last post by I need coffee, 3 d ago

BigG2

Discussion Starter · 6 d ago (Edited)

After a bit of advice, we have a 2009 Murano AWD with 119,000 miles on, a couple of days ago the engine light came on so I read the codes and was getting P0744 Torque Convertor, car was driving fine with no issues so i cleared the code and drove the car again with no issues. Used it again today end the light came back on, cleared the code again and went to start the car but got slow starting, checked battery voltage which was only 9V so decided to fit a new battery, after the new battery was installed the slow starting disappeared but on the 2nd ignition cycle the same fault code returned which i again cleared, on my way back from a test drive the car started making a weird grating/whining noise and drive to the wheels was lost so i coasted for a while until i came to a stop, I re-started the car and managed to drive approx 0.5 miles very slowly to get home, now when i put the car in D it does not move at all and limits the revs to about 2000, at the moment i have no warning lights for either CVT or Engine. I am a decent DIY mechanic but know my limitations, is it better to go straight to a specialist with these sorts of faults or is there anything i can try myself?
By the way the CVT fluid was renewed approx 2 years ago, it is now an amber colour which I believe is normal? Level is good.

Could it literally be just the torque convertor unit itself that has failed and needs replacement?

Thanks in advance for any replies!!

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chidog

· #2 · 5 d ago

Check all the battery cables for corrosion, that means the ground wire to every place it is connected to. If the wire looks bad replace it.
The ground connects to the body and to the transmission. It will cause all kinds of problems if not clean and has good contact. Even if it looks good take them off and clean em.

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BigG2

Discussion Starter · #3 · 5 d ago

chidog said:
Check all the battery cables for corrosion, that means the ground wire to every place it is connected to. If the wire looks bad replace it.

Thanks for the reply - i will definitely do that, one other thing i noticed is that when i installed the new battery the voltage without the car running was around 12.5V which i think is normal but with the car running it only increased up to 13.2V which seems a little low to me - i thought normal charging voltage from the alternator was higher than that? Do you genuinely think that this could be causing the CVT issues?

Thanks.

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MuranoSL2003

· #4 · 4 d ago

BigG2 said:
Thanks for the reply - i will definitely do that, one other thing i noticed is that when i installed the new battery the voltage without the car running was around 12.5V which i think is normal but with the car running it only increased up to 13.2V which seems a little low to me - i thought normal charging voltage from the alternator was higher than that? Do you genuinely think that this could be causing the CVT issues?

Thanks.

If the battery is at fully charged at the time your checked it the 13.2 volts may be normal. Check it just after a cold start, it should be over 14 volts.

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BigG2

Discussion Starter · #5 · 4 d ago

I checked the voltage today on a cold start although it was quite warm when i did it, it was around 22degC, my findings were:

(Measured on battery terminals)
Battery Voltage prior to start: 12.5V
Battery Voltage on start: 14.2V
Battery Voltage approx 20 seconds after start: 13.6V
Battery Voltage approx 60 seconds after start: 13.2V

I would say that this seems OK to me?

I have re-read the codes with the CVTz50 app and am getting P0744 & P0868, i took a couple of screenshots showing the PRI & SEC Pressure and the Target pressures, the 1st image shows the car in D with some revs applied but there was no pressure on either PRI or SEC pressures - in this state the car wont move at all, the 2nd image shows the car in P at idle but shows very minimal pressure, when i go into D in this state and rev the the car it will move very slowly just a little.

Again - any replies/advice appreciated.

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MuranoSL2003

· #6 · 3 d ago

BigG2 said:
I checked the voltage today on a cold start although it was quite warm when i did it, it was around 22degC, my findings were:

(Measured on battery terminals)
Battery Voltage prior to start: 12.5V
Battery Voltage on start: 14.2V
Battery Voltage approx 20 seconds after start: 13.6V
Battery Voltage approx 60 seconds after start: 13.2V

I would say that this seems OK to me?

Yes, those voltages look normal to me. It looks like your battery and alternator are healthy.

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canWat

· #7 · 3 d ago

BigG2 said:
I checked the voltage today on a cold start although it was quite warm when i did it, it was around 22degC, my findings were:

(Measured on battery terminals)
Battery Voltage prior to start: 12.5V
Battery Voltage on start: 14.2V
Battery Voltage approx 20 seconds after start: 13.6V
Battery Voltage approx 60 seconds after start: 13.2V

I would say that this seems OK to me?

I have re-read the codes with the CVTz50 app and am getting P0744 & P0868, i took a couple of screenshots showing the PRI & SEC Pressure and the Target pressures, the 1st image shows the car in D with some revs applied but there was no pressure on either PRI or SEC pressures - in this state the car wont move at all, the 2nd image shows the car in P at idle but shows very minimal pressure, when i go into D in this state and rev the the car it will move very slowly just a little.

Again - any replies/advice appreciated.

View attachment 56551

View attachment 56552

P0868 is for low transmission fluid so I'd check for that.

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I need coffee

· #8 · 3 d ago

P0868 is a low line pressure fault. The CVTz50 app is showing little to no primary or secondary line pressure. I think the transmission is probably going to have to be taken apart to fix this problem...

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